Review of three-dimensional holographic imaging by multiple-viewpoint-projection based methods◇
Natan T.Shaked,*Barak Katz,and Joseph Rosen
Department of Electrical and Computer Engineering,Ben-Gurion University of the Negev,
P.O.Box653,Beer-Sheva84105,Israel
*Corresponding author:natan.shaked@https://www.doczj.com/doc/6113718963.html,
Received2July2009;revised2September2009;accepted2September2009;
posted8September2009(Doc.ID113711);published9October2009
Methods of generating multiple viewpoint projection holograms of three-dimensional(3-D)realistic ob-
jects illuminated by incoherent white light are reviewed in this https://www.doczj.com/doc/6113718963.html,ing these methods,it is possible
to obtain holograms with a simple digital camera,operating in regular light conditions.Thus,most dis-
advantages characterizing conventional digital holography,namely the need for a powerful,highly co-
herent laser and extreme stability of the optical system,are avoided.The proposed holographic processes
are composed of two stages.In the first stage,regular intensity-based images of the3-D scene are cap-
tured from multiple points of view by a simple digital camera.In the second stage,the acquired projec-
tions are digitally processed to yield the complex digital hologram of the3-D scene,where no interference
is involved in the process.For highly reflecting3-D objects,the resulting hologram is equivalent to an
optical hologram of the objects recorded from the central point of view.We first review various methods to
acquire the multiple viewpoint projections.These include the use of a microlens array and a macrolens
array,as well as digitally generated projections that are not acquired optically.Next,we show how to
digitally process the acquired projections to Fourier,Fresnel,and image holograms.Additionally,to ob-
tain certain advantages over the known types of holograms,the proposed hybrid optical-digital process
can yield novel types of holograms such as the modified Fresnel hologram and the protected correlation
hologram.The prospective goal of these methods is to facilitate the design of a simple and portable digital
holographic camera that can be useful for a variety of practical applications,including3-D video acquisi-
tion and various types of biomedical imaging.We review several of these applications to signify the ad-
vantages of multiple viewpoint projection holography.?2009Optical Society of America
OCIS codes:090.1995,090.1760,100.3010,170.3880.
◇Datasets associated with this article are available at https://www.doczj.com/doc/6113718963.html,/10376/1444.
1.Introduction
Holography is able to provide the most authentic three-dimensional(3-D)illusion to the human eye, with accurate depth cues,without the need for spe-cial viewing devices,and without causing eye strain [1,2].For visualization purposes,the holographically recorded3-D image can be easily reconstructed opti-cally(for example by illuminating the hologram with a coherent light).In addition,holograms have advan-tages as a storage medium of3-D models since the acquired3-D information can be stored within holo-grams in a very dense,efficient,and encrypted way [the entire volume is stored in a two-dimensional (2-D)complex matrix].However,the conventional op-tical holographic recording process requires a coher-ent,powerful laser source and an extreme stability of the optical system,as well as long developing process of the recorded hologram.
In digital holography[3],a digital camera is used as the recording medium instead of the photographic plate or film,and thus no chemical development pro-cess is needed.This allows real-time acquisition and
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digital processing and reconstruction of the acquired holograms.However,the other strict conditions needed for the conventional optical holographic re-cording process still stay the same.The practical meaning of these restrictions is that conventional digital holograms cannot be recorded outside a well-equipped optical laboratory.Therefore,many practical applications requiring3-D imaging have not employed holography notwithstanding its many attractive advantages described above.
By developing new holographic techniques for in-coherently illuminated3-D scenes,it is possible to eliminate most of the limitations of the laser-based holographic recording process.Old techniques of re-cording incoherent holograms are based on the fact that an object,illuminated by a spatially incoherent and quasi-monochromatic light,is composed of many points,each of which is self-spatially coherent and thus can create an interference pattern with the light coming from the mirrored image of the point[4–10].
A different approach for generating holograms of incoherently illuminated3-D scenes is the scanning holography[11–13].In this technique,digital Fres-nel holograms are obtained,under spatially incoher-ent illumination,by scanning the3-D scene with a pattern of a Fresnel zone plate,so that the light in-tensity at each scanning position is integrated by a point detector.Scanning holography is widely used and has been discussed in many articles.However, this technique requires time-consuming mechanical scanning and relatively complicated laser align-ments.A possible solution to these problems could be Fresnel zone-plate coded holography[14],which is based on a motionless correlation between the ob-jects and Fresnel zone plates.However,this techni-que has not yielded acceptable imaging performance in the optical regime.
Another motionless technique for obtaining digital incoherent Fresnel holograms,called FINCH(Fres-nel incoherent correlation holography),has been re-cently proposed in Refs.[15–18].In this technique, the spatially incoherent and quasi-monochromatic light coming from the3-D scene propagates through or is reflected from a diffractive optical element (DOE)and is recorded by a digital camera.The phase function of the DOE creates two spherical waves from each object point,so that the final intensity re-corded by the camera is similar to the intensity of a conventional on-axis interference hologram.To avoid the twin-image problem[1,2]in the hologram re-construction,three different holograms,each with a different phase factor of the DOE,are recorded se-quentially and superposed in the computer into the final Fresnel hologram.This technique is able to ob-tain reconstructed3-D images with high resolution, without using physical scanning or complicated laser alignments as required in the scanning holographic technique.Still,the main disadvantage of the FINCH technique is that three different holograms of the same3-D scene have to be acquired to yield the final hologram.Thus,the ability of this technique to acquire dynamic3-D scenes(scenes that might be changed during the three hologram acquisitions)is limited.In addition,technical limitations of the spa-tial light modulator(SLM)used to display the three DOE phase functions,may cause the hologram recon-struction to have low signal-to-noise ratio,especially if the objects in the3-D scene are complicated[19]. Multiple viewpoint projection(MVP)holography is a relatively new technique for generating digital and optical holograms of3-D real-existing objects under regular“daylight”(temporary incoherent and spa-tially incoherent)illumination.To obtain these holo-grams,a conventional digital camera is used.The process does not require recording wave interference at all,and thus the twin image problem is avoided. MVP holograms are generated by first acquiring two-dimensional(2-D)projections(regular intensity images)of a3-D scene from various perspective points of view.Then,the acquired MVPs are digitally processed to yield the digital hologram of the scene. In contrast to the composite hologram[20,21],an MVP hologram is essentially equivalent to a conven-tional digital hologram of the scene recorded from the central point of view(under the assumption that there are no phase objects in the3-D scene).The MVP acquisition process is performed under incoher-ent illumination,where neither an extreme stability of the optical system nor a powerful,highly coherent laser source is required as in conventional techni-ques of recording holograms.
Once the MVP hologram is generated,it can be decided whether to reconstruct the recorded3-D scene optically or digitally.One method to recon-struct the3-D scene optically is to encode the MVP hologram into a computer-generated hologram (CGH)[1,2,22]with real and positive transparency values,and to print the CGH on a slide,or to display it on an SLM.Then,the recorded3-D scene can be reconstructed by illuminating the CGH with a coher-ent beam[1,23].Alternatively,the recorded3-D scene can be reconstructed digitally by Fresnel back-propagator[3,23],which actually means convolving the complex matrix of the MVP hologram with quad-ratic phase functions scaled according to the various axial reconstruction distances.
As mentioned above,the overall process of gener-ating the MVP hologram can be divided into two main stages:the optical acquisition stage and the digital processing stage.In the optical acquisition stage,MVPs of the3-D scene are captured,whereas in the digital processing stage,mathematical opera-tions are performed on these perspective projections to yield a complex function representing the digital hologram of the3-D scene.Section2reviews various MVP acquisition methods,whereas Section3reviews several methods of processing the acquired MVPs to different types of holograms.Section4reviews sev-eral possible applications for this technology,and Section5concludes the paper.
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2.Optical Acquisition of the Multiple
Viewpoint Projections
Capturing the MVPs can be performed in several ways,which include shifting the digital camera me-chanically,utilizing a microlens array for acquiring viewpoint projections simultaneously,or acquiring only a small number of extreme projections and predicting the middle projections digitally using a 3-D interpolation algorithm.These MVP acquisition methods are reviewed in the following subsections.
A.Shifting the Camera
In Refs.[24–28],the MVPs were acquired by shifting the camera mechanically,so that the camera cap-tured only a single perspective projection at each location.This method was first implemented for gen-erating MVP holograms,as it does not require any special hardware or capturing algorithms.However, this acquisition process is quite slow.For example,a 2-D MVP hologram with256×256pixels requires 65,536MVPs(since,as we show in Section3,each perspective projection yields a single pixel in the 2-D MVP hologram).This is a large number of MVPs, and capturing them by manual mechanical move-ments is a quite slow and problematic procedure.
A step motor has been used to make this process fas-ter and more accurate.However,the mechanical movement of the camera,even if performed by using the step motor,is not adequate when the object moves faster than one acquisition cycle,since the wrong MVPs would be captured in this situation. Therefore,alternative capturing methods are needed,and those are described next.
B.Spatial Multiplexing for Completely-Optically Acquiring Multiple Viewpoint Projections
To avoid mechanical movements of the camera,the acquisition of the MVPs can be accomplished by spa-tial multiplexing.Positioning several cameras in an array is one option to do this.However,the method requires multiple cameras,and as a result the en-tire camera array is quite expensive.Instead,in Ref.[29],it was proposed to use a microlens array to capture simultaneously a large number of MVPs in a single camera shot.This acquisition method is similar in some respects to that usually used in the integral imaging field[30,31].However,in the present case the goal is to produce an incoherent hologram that can,for example,be reconstructed op-tically,without the use of the microlens array or the multiple elemental images again,as needed in inte-gral imaging.Additionally,in contrast to MVP holo-graphy,in most integral imaging methods only a small part of the3-D scene(a subimage)is viewed by each microlens in the array,whereas in our case the entire3-D scene is viewed by each microlens.Re-ference[32]presents a different method,in which subimages,rather than the full projections,are first captured by the microlens array and then used to generate the MVP hologram.
Figure1(a)shows the experimental setup used for directly capturing the multiple full-scene projections by the microlens array.A plano–convex lens L1,posi-tioned at a distance of its focal length f1from the3-D scene,is attached to the microlens array and utilized to collimate the beams coming from the3-D scene and thus to increase the number of microlenses par-ticipating in the process.A spherical lens L2projects the microlens array image plane upon the
camera Fig.1.Integral holography—MVP holography using a microlens array[29].(a)Optical system for capturing the MVPs.(b)Several projections taken from different parts of the microlens array image plane captured by the https://www.doczj.com/doc/6113718963.html,rger part of this image plane is shown in View1and Media1.(c)Magnitude(left)and phase (right)of the2-D Fourier hologram obtained after performing the processing stage on the captured projections;(d)Best-in-focus reconstructed planes obtained by digital Fresnel propagation. Note that(b)–(d)are contrast-inverted.The continuous Fresnel propagation as2-D slices and the entire reconstructed volume are shown in View2,as well as in Media2and Media3(best-in-focus axial points are amplified).
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with the magnification of?z2=z1.Then,the camera captures the entire microlens array image plane in a single exposure and sends the image to the compu-ter for the processing stage.Figure1(b)shows sev-eral selected projections cut from different parts of the overall microlens-array image plane which is re-corded by the camera.Part of the entire image plane is illustrated in View1and Media1.As shown in Fig.1(b),the gap between the two letter objects is changed depending on the location of the projection on the image plane.This is the effect that leads to the 3-D volumetric properties of the hologram obtained in the end of the digital process.Following the acqui-sition of the MVPs,different types of MVP holograms can be generated according to the specific digital pro-cess carried out on the acquired projections.These possible digital processes are discussed in Section3. Figure1(c)shows the amplitude and the phase of the 2-D complex Fourier hologram(the digital process of which is described in Subsection3.B)that has been produced from the acquired projections.Reconstruct-ing this hologram can be done optically,by illuminat-ing it with a coherent converging spherical wave,or alternatively,digitally by first computing the holo-gram’s inverse Fourier transform(IFT),and then si-mulating a Fresnel propagation to reveal different planes along the optical axis of the3-D reconstructed image.The two best-in-focus reconstructed planes are shown in Fig.1(d).The fact that in each recon-structed plane only a single letter,the“I”or the“H,”is in focus whereas the other letter,the“H”or the“I,”respectively,is out of focus validates that a volume information is indeed encoded into the hologram. View2as well as Media2and Media3show the con-tinuous Fresnel propagation along the optical axis slice by slice and the entire reconstructed volume. In spite of the advantages of the method described above,generating a high-resolution hologram re-quires an array with more microlenses,because each projection yields only a single pixel in the2-D com-plex matrix of the MVP hologram.However,since the total size of the microlens array is limited(as well as the digital camera imager size),having more micro-lenses in the array leads to a small diameter of each microlens.This results in a low resolving power of each microlens(as well as in a low number of camera pixels assigned to the elemental image from each mi-crolens),causing a poor imaging resolution of the perspective projections.On the other hand,having microlenses with larger diameters leads to better projection resolution,but then fewer microlenses can be used,and hence there are fewer pixels in the re-sulting hologram.
C.Shifting the Camera and Digital Postprocessing
To solve the problem mentioned in the end of the pre-vious subsection,Ref.[33]has presented a possible way to reduce the number of MVPs,so that the cam-era acquires only a small number of perspective pro-jections with high resolution,typically the extreme ones.Then the computer synthesizes the middle pro-jections by using a3-D interpolation algorithm called the view synthesis algorithm[34,35].Given two viewpoint projections,the algorithm first calculates the correspondence map,containing the displace-ments of each pair of corresponding pixels in the two given projections,and then predicts how the scene would look from new middle viewpoints by interpo-lating the locations and intensity values of the corre-sponding pixels in the two given projections.A schematic of the method is illustrated in Fig.2(a)
. Fig.2.Synthetic projection holography(SPH)—optically acquir-
ing only a small number of projections and synthesizing the middle MVPs by the view synthesis algorithm[33]:(a)Schematics of the experimental setup.Only two projections are optically acquired. The entire MVP set(including the synthesized projections)is shown in View3and Media4.(b)Magnitude(left)and phase (right)of the1-D Fourier hologram obtained from the final set of MVPs.(c)Best-in-focus reconstructed planes.The continuous Fresnel propagation as2-D slices and the entire reconstructed volume are shown in View4,as well as in Media5and Media
6(best-in-focus axial points are amplified).
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View3and Media4show the entire set of MVPs gen-erated by the process.Again,a relative“movement”of the different objects can be seen throughout the MVPs.However,this time,this“movement”is on the horizontal axis only,since the two original projec-tions were optically acquired on the horizontal trans-verse axis.After synthesizing all the(optically and digitally obtained)projections,an MVP hologram was computed.The hologram shown in Fig.2(b)is a one-dimensional(1-D)Fourier hologram generated by the process explained in Subsections 3.A and 3.B.The best-in-focus planes obtained from this holo-gram are shown in Fig.2(c),illustrating that,al-though only two perspective projections are optically acquired,a good quality3-D reconstructed image can still be obtained.View4as well as Media5and Media6show the continuous Fresnel propagation along the optical axis slice by slice and the entire reconstructed volume.
In Ref.[33],the camera moved mechanically to ac-quire the MVPs.Therefore,in spite of reducing the number of the acquired MVPs and capturing pro-jections in an acceptable resolution,there is still a problem in utilizing this acquisition method for gen-erating holograms of dynamic scenes.
D.Spatial Multiplexing Using a Macrolens Array and Digital Postprocessing
To generate MVP holograms of dynamic scenes and still be able to get an acceptable resolution of each projection,we hybridized in Ref.[36]both methods presented in Refs.[29,33].This is performed by building the3×3macrolens array shown in Fig.3(a). To produce this array,we used nine standard nega-tive lenses,each of which had a focal length of?25cm and an original diameter of5cm.To take advantage of the entire array size,each lens was cut into a square of3:53×3:53cm,and a3×3macrolens array of10:6×10:6cm was formed by attaching the cut lenses with an optical adhesive.Figure2(b)shows 3×3projections acquired by the macrolens array in one camera exposure.The macrolens array pro-vides a convenient way to capture a small number
of projections on a2-D grid simultaneously.Thus,it is possible to acquire the projections of a dynamic scene.After the projections are acquired,the view synthesis algorithm is applied so that the middle pro-jections are digitally synthesized.Then,a2-D MVP hologram of the3-D scene can be generated by apply-ing one of the digital processes described in the next section on the entire set of perspective projections.
3.Hologram Generation by Digital Processing of the Multiple Viewpoint Projections
Following the acquisition of the MVPs,the digital processing stage is carried out to yield the digital ho-logram of the3-D scene.Our group has shown [24,25,28,29,33,36–38]that by processing the MVPs it is possible to generate Fourier,Fresnel,image, modified Fresnel,and protected correlation holo-grams.In addition,for each of the above types,it is possible to generate both1-D and2-D MVP holo-grams.This section reviews the digital processes to obtain each of these holograms.
A.One-Dimensional and Two-Dimensional Holograms Both1-D MVP holograms[24,33,37,38]and2-D MVP holograms[25–29,32,36,38]can be produced,accord-ing to the MVP acquisition axes and the subsequent digital processing.The1-D holograms are easier to produce because in this case the MVPs are captured along a single transverse axis only,unlike the2-D ho-lograms in which the MVPs are captured on a trans-verse2-D grid.On the other hand,2-D holograms have the advantage of encoding the3-D information into the two transverse axes,and thus2-D(rather than a1-D)volumetric effects are obtained in the 3-D image reconstructed from the hologram.In case of the2-D MVP hologram,the digital
process Fig.3.Acquiring a small number of high-resolution projections in a single digital camera exposure using a macrolens array[36]: (a)Photo of the3×3macrolens array.(b)Image plane of the macrolens array captured by the camera in a single exposure.
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includes multiplication of each projection by a cer-
tain complex point spread function(PSF)and sum-
mation of the resulting inner product to the
corresponding pixel in the hologram matrix.On
the contrary,in case of the1-D MVP hologram,the
sum of the1-D inner product is the corresponding col-
umn in the hologram matrix.
For mathematical presentation of the digital pro-
cess in case of the1-D MVP hologram,let us assume
thate2Kt1Tprojections of the3-D scene are ac-
quired along the horizontal axis only.We number
the projections by m,so that the middle projection
is denoted by m?0,the right projection by m?K,
and the left projection by m??K.Then,to generate
the1-D MVP hologram of the scene,any row of the m th projection P m is multiplied by a certain PSF and the products are summed to theem;nTth pixel in a
complex matrix as follows:
H1em;nT?Z Z
P mex p;y pTE1ex p;y p?nΔpTd x p d y p;
e1T
where E1ex p;y pTrepresents the generating PSF of the1-D hologram,x p and y p are the axes on the pro-jection plane,n is the row number in the complex ma-trix H1,andΔp is the pixel size of the digital camera. E1ex p;y pTis defined as the following:
E1ex p;y pT?A1eb x x pTexp?ig1eb x x pT δey pT;e2T
where A1and g1are certain functions dependent on x p and may be defined differently for each type of MVP hologram;b x is an adjustable parameter(with units that preserve the arguments of A1and g1 as unitless quantities),which may or may not be de-pendent on the projection index m;andδis the Dirac delta function.According to Eq.(1),each projection contributes a different column to the complex matrix H1em;nT,which represents,in the end of the digital process,the1-D MVP hologram of the3-D scene. Excluding Fourier holograms[in which pre-liminary1-D IFT and convolution with1-D quadratic phase function are used],to digitally obtain the reconstructed planar image s1em;n;z rTlocated at ax-ial distance z r from the1-D hologram,the hologram is digitally convolved with a reconstructing PSF as follows:
s1em;n;z rT?j H1em;nT?R1em;n;z rTj;e3T
where?denotes a1-D convolution,and R1em;n;z rTis the reconstructing PSF of the1-D hologram.This PSF is given by
R1em;n;z rT?A1
mΔp
z r
exp
?ig1
mΔp
z r
δenΔpT;
e4T
where A1and g1are the same functions used for the
generating PSF of the1-D hologram[Eq.(2)].
To present a similar mathematical description for
the case of the2-D MVP hologram,let us assume that
horizontal(2Kt1)by vertical(2Kt1)MVPs are ac-
quired on a2-D transverse grid.We number the pro-
jections by m and n,so that the middle projection is
denoted byem;nT?e0;0T,the upper-right projection
byem;nT?eK;KT,and the lower-left projection by
em;nT?e?K;?KT.Then,to generate a2-D MVP ho-
logram,theem;nTth projection P m;nex p;y pTis multi-
plied by a certain PSF and the product is summed
to theem;nTth pixel in a complex matrix as follows:
H2em;nT?
Z Z
P m;nex p;y pTE2ex p;y pTd x p d y p;e5T
where E2ex p;y pTrepresents the generating PSF
of the2-D hologram.This PSF is defined as the
following:
E2ex p;y pT?A2eb x x p;b y y pTexp?ig2eb x x p;b y y pT ;e6T
where A2and g2are certain functions dependent on
ex p;y pTand may be defined differently for every type
of MVP hologram as discussed below.b x and b y are
adjustable parameters(with units that preserve the
arguments of A2and g2as unitless quantities),which
may or may not be dependent on m and n.The pro-
cess manifested by Eq.(5)is repeated for all the pro-
jections,but in contrast to the1-D case,in the2-D
case each projection contributes a single pixel to
the hologram matrix rather than a column of pixels.
In the end of this digital process,the obtained2-D
complex matrix H2em;nTrepresents the2-D MVP
hologram of the3-D scene.
Excluding Fourier holograms(in which prelimin-
ary2-D IFT and convolution with2-D quadratic
phase function are used),the reconstructed planar
image s2em;n;z rTlocated at an axial distance z r from
the2-D hologram is obtained by digitally convolving
the hologram with a reconstructing PSF as follows:
s2em;n;z rT?j H2em;nT?R2em;n;z rTj;e7T
where?denotes a2-D convolution this time and
R2em;n;z rTis the reconstructing PSF of the2-D ho-
logram.This PSF is given by
R2em;n;z rT?A2
mΔp
z r
;
nΔp
z r
×exp
?ig2
mΔp
z r
;
nΔp
z r
;e8T
where A2and g2are the same functions used for the
generating PSF of the2-D hologram[Eq.(6)].The re-
constructing PSFs given by Eqs.(4)and(8)are used
for a digital reconstruction.Optical reconstruction of
Fourier,Fresnel,and image holograms can be per-
formed by illuminating them with a coherent wave
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(plane wave in case of Fresnel and image holograms and spherical converging wave in the case of the Fourier hologram).Even if a new type of digital ho-logram is defined by the MVP technique,an optical reconstruction of this hologram can still be obtained by digitally converting this hologram to a regular type of hologram(such as Fourier,Fresnel,or image holograms).Another possibility to obtain an optical reconstruction in these cases is using an optical cor-relator[39].
As an example of a specific reconstructing PSF, Fresnel propagation can be implemented digitally using Eq.(7),where in this case R2em;n;z rTis a2-D quadratic phase function given by
R2em;n;z rT?exp
?i
emΔpT2tenΔpT2
z r
:e9T
After choosing the hologram dimensionality(1-D or2-D),several types of MVP holograms can be gen-erated depending on the choice of the PSF used to multiply the MVPs.Several types of MVP holograms have been reported in the literature.These include Fourier holograms[24–29,33],Fresnel holograms [26–28],Fresnel–Fourier holograms[28],and image holograms[28].In addition,it is also possible to produce new types of holograms in order to obtain various advantages over the known types of holo-grams[37,38].
B.Fourier Holograms
To generate a1-D MVP hologram,Eq.(1)should be used,where the generating PSF of the1-D Fourier hologram is defined as follows:
E1ex p;y pT?expeibmx pTδey pT;e10T
where b is an adjustable parameter.Similarly,in or-der to use the MVPs to generate a2-D MVP Fourier hologram,Eq.(5)should be used,where the generat-ing PSF of this hologram is given by
E2ex p;y pT?exp?ibemx ptny pT :e11T
This means that the generation of MVP Fourier ho-lograms is performed by multiplying each of the MVPs by a different linear phase function with a fre-quency that is dependent on the relative position of the projection in the entire projection set(m and n). In the mathematical proof of this method[24],it is shown that the method is valid only if we assume that the MVPs are acquired across a relatively nar-row angular range(30?40°).An example of a1-D MVP Fourier hologram is shown in Fig.2(b),and an example of a2-D MVP Fourier hologram is shown in Fig.1(c).
C.Fresnel and Image Holograms
According to Refs.[27,28],it is possible to generate Fresnel,image,and other types of holograms by using an MVP Fourier hologram generated before-hand.The basic idea is to take the MVP Fourier hologram obtained by the method elaborated in Sub-section3.B and IFT it.Then,by a digital Fresnel propagation[convolution with quadratic phase func-tions as defined by Eq.(9)],either a Fresnel hologram or an image hologram can be generated,depending on the propagation distance.
However,there are several disadvantages with this method.First,since the generation of the Fres-nel,or other types of Fourier-based holograms is performed indirectly,the resulting hologram is ap-proximated and inaccurate,as well as requires re-dundant calculations.Digital errors may also occur during the various transformations.In addition, since the original Fourier hologram is limited to small angles of acquisition,the resulting holograms are limited to small angles of acquisition as well.
D.Modified Fresnel Hologram(DIMFH)
To avoid these problems,the digital incoherent modified Fresnel hologram(DIMFH)has been pro-posed in Refs.[37,38,32].This Fresnel hologram can be generated by processing the MVPs straight-forwardly,without redundant calculations,approxi-mations,or assumptions.
The1-D DIMFH is generated by multiplying each projection by the1-D quadratic phase function
E1ex p;y pT?expei2πb2x2pTδey pT;e12Tand summing the product,according to Eq.(1),to a column in the final hologram matrix.Similarly,the 2-D DIMFH processing is carried out by multiplying each projection by the2-D quadratic phase function
E2ex p;y pT?exp?i2πb2ex2pty2pT ;e13Tand summing the product,according to Eq.(5),to the corresponding pixel in the final2-D hologram.The DIMFH is obtained by multiplying all the MVPs by the same quadratic PSF,independently of the pro-jection indices m and n(rather than multiplying the MVPs by a changing PSF as in the case of an MVP Fourier hologram).Since each projection is multi-plied by the same spatial function,this process is a spatial correlation between the observed3-D scene and the PSF.The movement required by the correla-tion operation occurs naturally due to the relative movements between the camera and the scene. The summation of the multiplications between the various projections and the preliminary-determined PSF completes the correlation operation,and an in-coherent correlation hologram is generated.The3-D information of the scene is stored in a Fresnel holo-gram due to the fact that each2-D transverse func-tion along the z axis is actually correlated with an effectively scaled quadratic phase function having different number of cycles.This is achieved due to parallax effect,according to which,throughout the MVPs,different objects located at different axial dis-tances have different“velocities”relative to the PSF,
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where the farther objects“move”slower than the closer objects.In contrast to other correlation holo-grams[40,41],the present hologram is created from real existing objects illuminated by incoherent white light and do not involve wave interference.
It has been shown in Refs.[37,28]that the trans-verse and the longitudinal magnifications of1-D in-coherent correlation holograms are given by
M1;x?Δp
α
;M1;y?
f
z s
?M;M1;z?
Δp
bfα
;
e14T
whereαis the gap between two adjacent projections, f is the focal length of the imaging lens,z s is the axial coordinate of the inspected object,and M is the mag-nification of the imaging lens.Similarly,the magni-fications of2-D incoherent correlation holograms are given by
M2;x?M2;y?Δp
α
;M2;z?
Δp
bfα
:e15T
It is evident from Eqs.(14)and(15)that contrary to the conventional imaging systems,the magnifica-tions of correlation holograms on the acquisition axes (x for the1-D case and x?y for the2-D case)are in-dependent from the axial positions of the objects in the3-D scene.This behavior is explained intuitively in the following.Although farther objects look smal-ler than closer objects in each captured projection, they also“move”slower throughout the projections because of the parallax effect.The slower“move-ment”broadens the correlation with the PSF in a way that the reduction of the image size in each pro-jection is precisely compensated by the increment of the correlation result size.This feature can be useful for3-D object recognition as shown in Subsection4.C. However,this effect can also be eliminated during the reconstruction process.To do this,the recon-structed image should be scaled by M=M1;x?ef=z sT=eΔp=αT?1=ebz rT[since z r=z s?Δp=ebfαT]across the acquisition axes for each and every reconstructed plane located at z r.This scaling process is demon-strated next for the1-D case.
To generate and reconstruct incoherent correlation holograms,we implemented,in Ref.[38],the opti-cal system illustrated in Fig.4(a).Three equal-size USAF resolution charts were printed and positioned at the scene in front of a dark background and were illuminated by a halogen white light.The digi-tal camera was positioned on a micrometer slider and captured1200projections of the3-D scene. Figure4(b)shows the two most-extreme and central projections out of the1200projections captured by the camera.The full set of MVPs is shown in View5 and Media7.Based on these projections,we gener-ated a1-D DIMFH,according to Eqs.(1)and(12), by multiplying each projection by the1-D quadratic phase function,and summing the result to the corre-sponding column in the hologram complex matrix. The amplitude and phase of the resulting1-D DIMFH are shown in Figs.5(a).According to Eqs.(3) and(4),the digital reconstruction of this1-D DIMFH was performed by1-D convolution of the hologram with1-D quadratic phase functions having a phase sign opposite to that of the generating PSF.The three best-in-focus reconstructing PSFs and the corre-sponding best-in-focus reconstructed planes are shown in Figs.5(b)and5(c),respectively.In each of the planes shown in Fig.5(c),a different USAF re-solution chart is in focus,whereas the other two charts are out of focus.This validates the success of the holographic process of the1-D DIMFH.As explained above,resampling(rescaling)these recon-structed planes along the horizontal axis is required for retaining the original aspect ratios of the objects. These resampled best-in-focus reconstructed planes are shown in Fig.5(d).Figure5(e)shows the corre-sponding zoomed-in images of the best in-focus charts.From this figure,one can conclude that the far objects in the3-D scene have a reduced horizontal reconstruction resolution compared to the close objects in the scene.
E.Protected Correlation Hologram(DIPCH)
The digital incoherent protected correlation holo-gram(DIPCH)[38]is another type of incoherent correlation hologram.This hologram has two advan-tages over the Fresnel hologram in general,and over the DIMFH in particular.First,since a random-constrained PSF is used to generate the hologram, only an authorized user who knows this PSF can re-construct the scene encoded into the hologram.Thus, the DIPCH can be used as a method of encrypting the observed scene.Second,the reconstruction obtained from the DIPCH,compared to the DIMFH,has a sig-nificantly higher transverse resolution for the far objects in the3-D
scene.
Fig.4.1-D MVP holography[38]:(a)Optical system for acquiring MVPs of a3-D scene along the horizontal axis.(b)Several projec-tions taken from the entire set of1200projections,which are shown in View5and Media7.
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The 1-D DIPCH process is still defined by Eqs.(1)and (3).However,this time the generating PSF is a space-limited random function that fulfills the con-straint that its FT is a phase-only function.In order to find this PSF ,we used the projection onto the con-straint sets (POCS)algorithm [42–45].The POCS algorithm used to find this PSF is illustrated in Fig.6(a).The POCS is an iterative algorithm that bounces from the PSF domain to its spatial-frequency spectrum domain and back,using an FT and IFT.In each domain,the function is projected onto the constraint set.The two constraints of the POCS express the two properties required for the PSF of the DIPCH.First,the FT of the PSF should be a phase-only function.This requirement enables to reconstruct the DIPCH properly.So,the constraint
of the POCS in the spectral domain is the set of all phase-only functions,and each Fourier transformed PSF is projected onto this constraint by setting its magnitude distribution to the constant 1.The other property of the PSF is that it should be space limited into a relatively narrow region close to but outside the origin.This condition reduces the reconstruction noise from the out-of-focus objects because the over-lap,occurring during the cross-correlation between the resampled space-limited reconstructing PSF and the hologram in out-of-focus regions,is lower than the overlap in case of using a widespread PSF .Of course,the narrower the existence region of the PSF ,the lower the noise is.However narrowing the existence region makes it difficult for the POCS algo-rithm to converge to a PSF that satisfies both con-straints within an acceptable error.In any event,the constraint set in the PSF domain is all of the com-plex functions that are identically equal to zero in any pixel outside the predefined narrow existence re-gion.The projection onto the constraint set in the PSF domain is performed by multiplying the PSF by a function that is equal to 1inside the narrow exis-tence region of the PSF and equals 0elsewhere.In the case of the 1-D DIPCH,the random-constrained PSF is limited to a narrow strip of columns,whereas in the case of the 2-D DIPCH,this PSF is limited to a narrow ring.In the end of the process,the POCS algorithm yields a suitable random-constrained PSF that is used in the hologram generation process.Figures 6(b)and 6(c)show the phase distributions of the resulting PSFs of the 1-D and the 2-D DIPCHs,respectively ,after applying the POCS algorithm for each of these cases.
Let us compare the reconstruction resolutions of the DIMFH and the DIPCH.Far objects captured by the DIMFH are reconstructed with a reduced resolu-tion because of two reasons:(a)Due to the parallax effect,farther objects “move ”slower throughout the projections,and therefore they sample a magnified version of the generating PSF .This magnified ver-sion has narrower bandwidth,and thus the recon-struction resolution of farther objects decreases.(b)The quadratic phase function used in the DIMFH has lower frequencies as one approaches its origin.Since far objects are correlated with the central part of the quadratic phase function along a range that becomes shorter as the object is farther,the band-width of the DIMFH of far objects becomes even nar-rower beyond the bandwidth reduction mentioned in (a).In contrast to the DIMFH,the spatial frequencies of the DIPCH ’s PSF are distributed uniformly all over its area.Therefore,the DIPCH sustain re-solution reduction of far objects only due to reason (a).Hence,the images of far objects reconstructed from the DIPCH,besides being protected by the random-constrained PSF ,also have higher trans-verse resolution.
In Ref.[38],the same MVPs of the 1-D DIMFH [part of which is shown in Fig.4(b)]have been used to generate a 1-D DIPCH.As mentioned above,
the
Fig.5.One-dimensional DIMFH results obtained from the MVP set,partially shown in Fig.4(b)[38]:(a)Magnitude (left)and phase (right)of the hologram.(b)Phase distributions of the reconstruct-ing PSFs used for obtaining the three best-in-focus reconstructed planes.(c)Corresponding three best-in-focus reconstructed planes along the optical axis.(d)Same as (c)but after the resampling along the horizontal axis.(e)Zoomed-in images of the correspond-ing best-in-focus reconstructed objects.
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digital process of the DIPCH includes multiplying each of the acquired projections by the random-constrained PSF computed by the POCS algorithm (Fig.6).Each inner product is summed to a single column in the 1-D DIPCH,the amplitude and phase of which are shown in Fig.7(a).To reconstruct this hologram,the DIPCH is convolved with the conju-gate of a scaled version of the same PSF used for the hologram generation.The phases of the three reconstructing PSFs yielding the best in-focus recon-structed planes are shown in Fig.7(b).The corre-sponding reconstructed planes are shown in Fig.7(c).As before,in each of these planes,a different USAF chart is in focus,whereas the other two charts are out of focus.Once again,a resamapling process has to
be
Fig.6.Finding the PSF of the DIPCH [38]:(a)Schematics of the POCS algorithm used.(b),(c)Phase distribution of the random-constrained PSF of the:(b)1-D DIPCH,and (c)2-D
DIPCH.
Fig.7.One-dimensional DIPCH results obtained from the MVP set,partially shown in Fig.4(b)[38]:(a)Magnitude (left)and phase (right)of the hologram.(b)Phase distribution of the reconstructing PSFs used for obtaining the three best-in-focus reconstructed planes.(c)Corresponding three best-in-focus reconstructed planes along the optical axis.(d)Same as (c)but after the resampling along the horizontal axis.(e)Zoomed-in images of the correspond-ing best-in-focus reconstructed objects.
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applied along the horizontal axis of the reconstructed planes to retain the original aspect ratios of the objects.Figure 7(d)shows these resampled best-in-focus reconstructed planes,whereas Fig.7(e)shows the corresponding zoomed-in images of the in-focus charts in these three https://www.doczj.com/doc/6113718963.html,paring Figs.5(e)and 7(e),we conclude that farther objects have a higher resolution in the DIPCH than in the DIMFH.This property signifies the advantage of the DIPCH over the DIMFH,while the other advantage of the DIPCH is that it is protected by the random-constrained PSF used for generating and recon-structing the hologram.
Tables 1and 2gather all the generating and recon-structing PSFs of the MVP holograms discussed in this paper for the 1-D and 2-D cases,respectively.
4.Selected Applications
The prospective goal of the presented MVP holo-graphic techniques is to yield a simple and portable digital holographic camera that works under regular illumination conditions and does not require special stability conditions.MVP holography might then be preferred whenever 3-D acquisition is required.This can make holography much more attractive to a variety of practical applications.We review several selected applications that signify the advantages of using MVP holography.
A.Real-Time 3-D Video Acquisition and Video Conferencing
As mentioned above,the MVP technique yields a ho-logram that is essentially equivalent to an optical ho-logram and thus can be easily reconstructed optically by illuminating it with a coherent wave.Thus,real-time video acquisition in general and video confer-encing over the internet in particular is one of the prospective applications of MVP holography .For the latter application,from the one side of the net,MVPs of a person can be acquired (using one of the parallel acquisition methods described in Sec-tion 2).Then,these projections can be digitally con-verted into a compressed form of 2-D complex matrix that is the digital hologram of this person ’s 3-D im-age (using one of the methods described in Section 3).For visualization of the 3-D image in the other side of the net,only a 2-D complex matrix has to be trans-ferred (rather than all the acquired MVPs or the entire volume).For this aim,even a limited data transfer rate over a modest internet connection can be enough.In the other side of the net,the 3-D image of the person can be reconstructed by dis-playing the complex hologram on an SLM (after en-coding it to a phase-only or an amplitude-only CGH [1,2,22],if required).Then,a coherent laser can be used to illuminate the SLM and project the 3-D im-age of the person from the first side of the net,where no special viewing device (e.g.,glasses)is needed.
Table 2.
Generating and Reconstructing PSFs of Various 2-D MVP Holograms
MVP Hologram Generating PSF
a
Reconstructing PSF
b
PSF Applied to PSF
Fourier c
exp ?i 2πb emx p tny p T 2-D IFT of the hologram exp
?i em Δp T2ten Δp T2
z r
DIMFH exp ?i 2πb 2ex p 2ty p 2T Hologram exp ?i em Δp T2ten Δp T2
z r
DIPCH
A 2eb x x p ;b y y p Texp ?ig 2eb x x p ;b y y p T
Hologram
A 2 m Δp z r ;n Δp z r exp ?ig 2 m Δp z r ;n Δp z r
where A 2and g 2are found by the POCS algorithm
a Multiply the PSF by the MVPs and sum to a hologram pixel.
b
Convolve the PSF by the hologram (or its 2-D IFT for Fourier hologram)to get the 3-D reconstructed image.c
Different propagation distances can create different types of 2-D MVP holograms,such as Fresnel and image 2-D MVP holograms.Table 1.Generating and Reconstructing PSFs of Various 1-D MVP Holograms
MVP Hologram Generating PSF a
Reconstructing PSF
b
PSF Applied to PSF
Fourier c
exp ei 2πbmx p Tδey p T1-D IFTof the hologram exp
?i em Δp T2
z r
δen Δp TDIMFH exp ei 2πb 2x 2p Tδey p T
Hologram exp ?i em Δp T2
z r
δen Δp TDIPCH
A 1eb x x p Texp ?ig 1eb x x p T δey p T
Hologram
A 1 m Δp z r exp ?ig 1 m Δp
z r
δen Δp Twhere A 1and g 1are found by the POCS algorithm
a Multiply the PSF by the MVPs and sum to a hologram column.
b
Convolve the PSF by the hologram (or its 1-D IFT for Fourier hologram)to get the 3-D reconstructed image.c
Different propagation distances can create different types of 1-D MVP holograms,such as Fresnel and image 1-D MVP holograms.
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B.Three-Dimensional Biomedical Imaging
MVP holography can be utilized for various biomedi-cal imaging applications.The straightforward appli-cations are remote surgeries and remote medical diagnoses,since,as described above,the MVP tech-niques can be used to capture 3-D objects in real time,transfer their 3-D images in a compressed ho-lographic way ,and then easily visualize the 3-D im-age in the remote side.Other applications that might be useful for biomedical imaging are 3-D fluorescence imaging and 3-D imaging through thin turbulent media (e.g.,thin biological tissues).
As shown in Ref.[36],the fluorescence phenomen-on,characterized by high sensitivity and low back-ground noise [46,47],can be utilized to acquire multicolor fluorescence holograms of 3-D scenes.The fluorescence is an incoherent radiation and thus suits the MVP holographic techniques.The experi-mental setup used to demonstrate this concept is shown in Fig.8(a).Several objects in the 3-D scene are labeled with fluorescent dyes and excited by blue light.Each time another set of projections of a differ-ent fluorescent color emitted from the labeled objects is simultaneously acquired through the macrolens array shown in Fig.3(a)and the corresponding chro-matic filter.Additional set of projections of the non-fluorescent white-light reflected from the scene is also acquired in a single camera exposure.The com-posite (red/green/gray)projections are shown in Fig.8(b).Then,a separate DIMFH is generated for each fluorescent color and for the nonfluorescent light.The magnitude and phase of one of these holo-grams are shown in Fig.8(c).Finally ,all recon-structed images from all the DIMFHs are digitally fused to yield a multicolor reconstruction of the 3-D scene.Figure 8(d)shows the best-in-focus recon-structed planes obtained at the axial distances of each of the three cube faces.Prospective application of the proposed method might be in vivo or ex vivo 3-D holographic imaging of biological objects that have been fluorescently labeled [46,47].
As shown in Ref.[48],MVP holography can also be used to perform 3-D optical imaging of objects em-bedded in a scattering medium.Performing this type of imaging is required for various applications.One of these applications is optical imaging for medical diagnostic purposes.In contrast to the widely used X-ray computed tomography (CT),medical optical imaging has the advantages of being nonionized,safe,and inexpensive.Various optical coherence tomography (OCT)and spectroscopy techniques [49,50]have been suggested as alternatives to CT.However,these methods usually require the use of low-coherence light sources and interferometeric op-tical setups,which imposes practical limitations on the optical systems.One approach to obtain 2-D imaging of objects embedded in biological tissues is the noninvasive optical imaging by speckle ensemble (NOISE)technique [51,52].According to this techni-que,the biological tissues are illuminated by a laser and observed from multiple perspective points
of
Fig.8.(Color online)Fluorescence 3-D imaging by MVP hologra-phy [36]:(a)Optical system for acquiring 3×3perspective projec-tions simultaneously using the macrolens array shown in Fig.3.Part of the objects in the scene are fluorescently labeled.(b)Com-posite image plane of the macrolens array acquired by the camera.(c)Magnitude (left)and phase (right)of the nonflorescence 2-D DIMFH.Two additional fluorescence 2-D DIMFHs are generated as well.(d)Three best-in-focus multicolor reconstructed planes.Viewing this figure in color online is highly recommended.
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view using a microlens array .The multiple perspec-tive images are first centered and then summed to a 2-D image of the embedded objects.Another version
of the NOISE technique performs the summation in the spectral domain [53].In addition,stereoscopic version of the NOISE technique was proposed for obtaining 3-D stereoscopic imaging of the embedded objects [54].Another method of performing a coher-ent nonholographic integral imaging of 3-D objects embedded in a scattering medium has been pre-sented by Moon and Javidi [55].
However,as mentioned above,holography has sev-eral advantages compared to stereoscopy ,as it is able to provide the most authentic 3-D illusion to the human eyes,without the need for special viewing de-vices,and it is also able to hold the 3-D information in a more compressed way .This signifies the advantage of 3-D incoherent holographic imaging of objects that are hidden behind a scattering medium.The method pro-posed in Ref.[48]was inspired by the NOISE techni-que.However,this time we viewed the scene from different perspectives to get holographic imaging of the 3-D scene,rather than simple 2-D imaging.In ad-dition,the capturing process was performed under in-coherent white-light illumination rather than using laser light as performed in the NOISE technique.The relevant experimental setup is shown in Fig.9(a).As shown in this figure,the incoherently illuminated scattering medium is mechanically ro-tated and vibrated,so that for each perspective view-point we acquire many spackled images through the medium and sum them to a relatively clear perspec-tive projection of the hidden 3-D scene.Then,the smoothed MVPs are used to generate a DIMFH of the hidden 3-D scene.
For comparison purposes,three different sets of projections were acquired.The first set is shown in View 6and Media 8,the middle projection of which is shown in Fig.9(b).This set was acquired without the presence of the diffuser (capturing the MVPs of the 3-D scene directly).The second set is shown in View 7and Media 9,the middle projection of which is shown in Fig.9(c).This set was acquired through a stationary diffuser (without activating the electric motor).The third set is shown in View 8and Media 10,the middle projection of which is shown in Fig.9(d).This set was acquired through the rotated/vibrated diffuser,where we averaged many speckled projections from the same point of view by increasing the exposure time of the digital camera.Based on these three sets of MVPs,three 1-D DIMFHs were generated.The magnitude and phase of one of these holograms are shown in Fig.9(e).Each one of these three holograms was reconstructed digitally.Fig-ures 9(f)–9(h),respectively ,show the final (rescaled)best-in-focus reconstructed planes obtained from the DIMFHs of the 3-D scene without the presence of the diffuser,when the scene is hidden behind a station-ary diffuser,and when the scene is hidden behind a rotated/vibrated diffuser (and projection averaging is performed prior to the DIMFH generation).The coinciding continuous Fresnel propagations along the optical axis slice by slice and the resulting re-constructed volumes are shown in View 9,View
10
Fig.9.MVP holography of a 3-D scene hidden behind a turbulent medium under incoherent illumination [48]:(a)Schematics of the experimental setup;(b)–(d)The middle perspective projection of the 3-D scene directly acquired by the digital camera (views and media references show the entire sets of 1100projections each):(b)without a diffuser (View 6and Media 8),(c)through a stationary diffuser (View 7and Media 9),and (d)through a ro-tated/vibrated diffuser (View 8and Media 10);(e)Magnitude (left)and phase (right)of the 1-D DIMFH generated without a diffuser.Similar DIMFHs were generated for the two other cases as well.(f)–(i)Best-in-focus reconstructed planes obtained from the DIMFHs that where generated (views and media references show the continuous Fresnel propagation as 2-D slices and the entire reconstructed volume.Axial best-in-focus points are amplified):(f)without a diffuser (View 9and Media 11and Media 12),(g)through a stationary diffuser (View 10and Media 13and Media 14),(h)through a rotated/vibrated diffuser (View 11and Media 15and Media 16),and (i)after applying the blind deconvolution algo-rithm (View 12and Media 17and Media 18).
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and View11,as well as in Media11/Media12, Media13/Media14,and Media15/Media16, respectively.Figure9(h)presents a significant improvement compared to Fig.9(g).Further im-provement was obtained by performing a blind con-volution according to the algorithm presented in Ref.[56].This algorithm finds the best step-edge in each reconstructed plane of the3-D image without prior knowledge of the hidden3-D scene.In the next stage,the derivative of the monotonic-gradient area in the chosen step edge is calculated.Following the theorem that the derivative of the step response function is equal to the impulse response function, and assuming isotropic blurring statistics,the deri-vative of the step edge(selected at any direction) would be a good approximation of the impulse re-sponse of the system.Finally,the improved recon-structed plane is obtained by Wiener filtering that uses the calculated impulse response function.The result of this process is an improved3-D image, the best-in-focus planes of which are shown in Fig.9 (i).The coinciding continuous Fresnel propagation along the optical axis slice by slice and the resulting reconstructed volume are shown in View12,as well as in Media17and Media18.A unique advantage of this blind deconvolution algorithm for digital holo-graphy is that it improves the images of focused ob-jects in each reconstructed plane more than the images of the unfocused objects(the ones that are not located at the proper axial distance in the real 3-D scene).We believe that in the future the proposed holographic method might be useful for noninvasive,safe,simple and low-cost3-D medical imaging,in-cluding observing3-D objects embedded in biological tissues.
C.Three-Dimensional Object Recognition
As mentioned in Subsection3.D,for the incoherent correlation holograms,a rescaling process should be applied to the reconstructed planes to retain the original perspective of the3-D scene,so that farther objects look smaller in the hologram recon-struction,as it usually happens in conventional imaging systems.However,as we have shown in Ref.[57],the constant-magnification effect can also be utilized to perform efficient optical3-D object re-cognition,since one can use only a single2-D filter to recognize(detect)all originally identical objects in the3-D scene,without dependency on their original axial distances from the acquisition plane(i.e.,no matter if they are far from or close to the digital cam-era).This is an important improvement compared to other optical holographic and nonholographic3-D ob-ject recognition methods[58–70],in which several matched filters had to be used to recognize the same objects located at different axial distances from the acquisition plane(e.g.,Ref.[63]),or averaging meth-ods had to be used to yield a scale-invariant filter at the expense of losing some of the correlation discri-mination between objects that should be recognized and objects that should be rejected(e.g.,Ref.[70]).So, the DIMFH can be used to perform efficiently optical 3-D object recognition.A nonholographic3-D object recognition method that has similar advantage
of Fig.10.(Color online)Three-dimensional object recognition under white light using incoherent correlation holography(taking into ad-vantage the constant magnification feature of the DIMFH)[57]:(a)Schematics of the entire process.Part of the200×200projection set is shown in View13and Media19.(b)–(g)Final correlation planes at the axial reconstruction distances of the:(b),(e)close tiger,(c),(f)goat, and(d),(g)distant tiger.Height axis:correlation intensity(A.U.).Ground axes:transverse coordinates.Higher correlation peaks indicate on better object recognition.(b)–(d)DIMFH-based results:a single filter is used to recognize both tigers simultaneously and reject the goat.(e)–(g)MVP-Fourier-hologram-based results(comparison to the old method,which does not have a constant magnification feature): by using a single filter,only the close tiger can be recognized,and both the distant tiger and the goat are rejected.(h),(i)Correlation values along the optical axis of the3-D correlation space for each of the three objects.The axial distance points for each of the objects are circled:(h)DIMFH-based results(both tigers are recognized),(i)MVP-Fourier-hologram-based results(old method,only the close tiger is recognized).
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having axial distance independency on the image size has been demonstrated in Ref.[71].
The electro-optical setup used to demonstrate the principle of incoherent-holographic3-D object recog-nition is shown in Fig.10(a).The3-D scene contained three objects,two identical tiger models and one goat model.The set of200×200MVPs,partially shown in View13and Media19,was acquired,where the goal was to use these MVPs to create an MVP hologram and then perform a convolution operation with a sin-gle2-D complex filter to recognize both the close and the distant tigers and reject the goat.This was achieved by obtaining high correlation peaks at the corresponding locations of the tigers in the corre-lation space,and a low correlation peak at the corre-sponding location of the goat in the correlation space. Figures10(b)–10(d)show surface plots of the re-sulting correlation planes located at the axial recon-struction distances of the animal models,when the hologram that was generated is a DIMFH.As seen in Fig.10(b),a distinct correlation peak appears at the close tiger transverse position,whereas in Fig.10(d)a distinct correlation peak appears at the distant tiger transverse position.On the other hand, any of the peaks that appear in Fig.10(c)(obtained at the axial reconstruction distance of the goat)is lower than the tigers’peaks[Figs.10(b)and10(d)].There-fore,although only a single filter was used,the two tigers could be easily recognized by the correlation process,whereas the goat could be rejected by this process since its peak was low even at its axial recon-struction distance[Fig.10(c)].Figure10(h)displays three correlation plots along the optical axis of the 3-D correlation space,at the transverse locations of the three objects.These graphs show that the cor-relation peaks of the two tigers are well-located in the3-D correlation space,although only a single fil-ter has been used in the correlation process.Thus, the method can reject the goat and recognize each of the two tigers,and it does not matter whether the tigers are close to or far from the acquisition plane.For comparison,we also generated an MVP Fourier hologram of the3-D scene and a phase-only filter which is matched to the close tiger. Figures10(e)–10(g)show the surface plots of the re-sulting correlation planes at the axial reconstruction distances of the animal models.As expected from this old method,only Fig.10(e),obtained at the axial re-construction distance of the close tiger,contains a distinct correlation peak.On the other hand,as shown in Fig.10(g),the correlation plane obtained at the axial reconstruction distance of the distant ti-ger contains several low correlation peaks,and thus the distant tiger will be wrongly rejected by the cor-relation process.Hence,in the old method,more than one filter is required to recognize the same objects located at different distances from the acquisition plane,which,as shown above,is not the case of the new(DIMFH-based)method.This conclusion is also obvious by comparing Figs.10(h)and10(i). The latter figure presents the correlation cross-section plots of the old method along the optical axis of the3-D correlation space at the transverse loca-tions of each of the three objects,demonstrating that only the close tiger can be recognized by the old method,whereas in the new method[Fig.10(h)],both tigers can be recognized by the correlation process.
5.Conclusions
In this paper,we have reviewed methods of generat-ing different types of MVP holograms.The MVPs of the3-D scene are captured by a simple digital cam-era,working under incoherent white-light illumina-tion,and then processed into a digital hologram of the scene by a simple digital process.Since no in-terference recording is needed,we avoid the con-ventional holographic recoding requirements for a coherent laser source and for an extreme stability of the optical system.We also avoid the twin-image problem present in interference-based holography. Using MVP holography,holograms can be captured outside of the laboratory,and many practical appli-cations may benefit from the attractive advantages of holography compared to other3-D acquisition methods.We have presented several different meth-ods of capturing the MVPs,such as mechanical move-ment of the camera,using microlens,macrolens,or camera arrays,as well as applying digital algorithms for interpolating middle MVPs.The digital process applied to the acquired projections determines the type of hologram generated.It has been shown that it is possible to generate both1-D and2-D MVP ho-lograms,and for each of them it is possible to gener-ate regular types of holograms such as Fourier holograms,Fresnel,and image holograms,as well as new types of holograms such as the DIMFH and the DIPCH.We have also reviewed selected applications of MVP holography.These include3-D video conferencing,remote surgeries and remote medical diagnosis,fluorescence holography,holo-graphic imaging behind a turbulent medium,and 3-D object recognition.These applications signify the importance of MVP holography to a variety of fields,in part of which holography has not been widely employed yet.
References
1.P.Hariharan,Optical Holography,Principles,Techniques and
Applications(Cambridge University Press,1996).
2.R.J.Collier,C.B.Burckhardt,and L.H.Lin,Optical Hologra-
phy(Academic,1971).
3.U.Schnars and W.Juptner,Digital Holography,Digital
Hologram Recording,Numerical Reconstruction and Related Techniques(Springer,2005).
4.A.W.Lohmann,“Wavefront reconstruction for incoherent ob-
jects,”J.Opt.Soc.Am.55,1555–1556(1965).
5.G.W.Stroke and R.C.Restrick,“Holography with spatially
noncoherent light,”Appl.Phys.Lett.7,229–231(1965).
6.H.R.Worthington,“Production of holograms with incoherent
illumination,”J.Opt.Soc.Am.56,1397–1398(1966).
7.G.Cochran,“New method of making Fresnel transforms with
incoherent light,”J.Opt.Soc.Am.56,1513–1517(1966). 8.P.J.Peters,“Incoherent holograms with a mercury light
source,”Appl.Phys.Lett.8,209–210(1966).
H134APPLIED OPTICS/Vol.48,No.34/1December2009
9.G.Sirat and D.Psaltis,“Conoscopic holography,”Opt.Lett.10,
4–6(1985).
10.A.S.Marathay,“Noncoherent-object hologram:its reconstruc-
tion and optical processing,”J.Opt.Soc.Am.A4,1861–1868 (1987).
11.T.-C.Poon,K.B.Doh,B.W.Schilling,M.H.Wu,K.Shinoda,
and Y.Suzuki,“Three-dimensional microscopy by optical scanning holography,”Opt.Eng.34,1338–1344(1995).
12.G.Indebetouw,P.Klysubun,T.Kim,and T.-C.Poon,“Imaging
properties of scanning holographic microscopy,”J.Opt.Soc.
Am.A17,380–390(2000).
13.B.W.Schilling,T.-C.Poon,G.Indebetouw, B.Storrie,
K.Shinoda,Y.Suzuki,and M.H.Wu,“Three-dimensional holographic fluorescence microscopy,”Opt.Lett.22, 1506–1508(1997).
14.L.Mertz and N.O.Young,“Fresnel transformations of
images,”Proceedings of Conference on Optical Instruments and Techniques,K.J.Habell,Ed.(Chapman&Hall,1962).
15.J.Rosen and G.Brooker“Digital spatially incoherent Fresnel
holography,”Opt.Lett.32,912–914(2007).
16.J.Rosen and G.Brooker“Fluorescence incoherent color holo-
graphy,”Opt.Express15,2244–2250(2007).
17.J.Rosen and G.Brooker,“Non-scanning motionless fluores-
cence three-dimensional holographic microscopy,”Nat.
Photon.2,190–195(2008).
18.J.Rosen,G.Indebetouw,G.Brooker,and N.T.Shaked,“A re-
view of incoherent digital Fresnel holography,”J.Holography Speckle5,124–140(2009).
19.T.-C.Poon,“Holography:Scan-free three-dimensional imag-
ing,”Nat.Photon.2,131–132(2008).
20.T.Yatagai,“Stereoscopic approach to3-D display using
computer-generated holograms,”Appl.Opt.15,2722–2729 (1976).
21.T.Mishina,M.Okui,and F.Okano,“Calculation of holograms
from elemental images captured by integral photography,”
Appl.Opt.45,4026–4036(2006).
22.J.W.Goodman,Introduction to Fourier Optics,2nd ed.
(McGraw-Hill,1996),pp.355–363.
23.T.Kreis,Handbook of Holographic Interferometry:Optical and
Digital Methods(Wiley-VCH,2005),Chap.3.
24.Y.Li,D.Abookasis,and J.Rosen,“Computer-generated holo-
grams of three-dimensional realistic objects recorded without wave interference,”Appl.Opt.40,2864–2870(2001).
25.D.Abookasis and J.Rosen,“Computer-generated holograms
of three-dimensional objects synthesized from their multiple angular viewpoints,”J.Opt.Soc.Am.A20,1537–1545 (2003).
26.Y.Sando,M.Itoh,and T.Yatagai,“Holographic three-dimen-
sional display synthesized from three-dimensional Fourier spectra of real-existing objects,”Opt.Lett.28,2518–2520(2003).
27.Y.Sando,M.Itoh,and T.Yatagai,“Full-color computer-
generated holograms using3-D Fourier spectra,”Opt.Express 12,6246–6251(2004).
28.D.Abookasis and J.Rosen,“Three types of computer-
generated hologram synthesized from multiple angular view-points of a three-dimensional scene,”Appl.Opt.45,6533–6538(2006).
29.N.T.Shaked,J.Rosen,and A.Stern,“Integral holography:
white-light single-shot hologram acquisition,”Opt.Express 15,5754–5760(2007).
30.B.Lee,S.Jung,and J.H.Park,“Viewing-angle-enhanced in-
tegral imaging by lens switching,”Opt.Lett.27,818–820 (2002).
31.A.Stern and B.Javidi,“Three dimensional sensing,visualiza-
tion,and processing using integral imaging,”Proc.IEEE94, 591–607(2006).32.J.-H.Park,M.-S.Kim,G.Baasantseren,and N.Kim,
“Fresnel and Fourier hologram generation using ortho-graphic projection images,”Opt.Express17,6320–6334 (2009).
33.B.Katz,N.T.Shaked,and J.Rosen,“Synthesizing
computer generated holograms with reduced number of perspective projections,”Opt.Express15,13250–13255 (2007).
34.D.Scharstein,View Synthesis Using Stereo Vision,Vol.1583of
Lecture Notes in Computer Science(Springer-Verlag,1999), Chap.2.
35.J.-S.Park, D.-C.Hwang, D.-H.Shin,and E.-S.Kim,“En-
hanced-resolution computational integral imaging recon-struction using an intermediate-view reconstruction technique,”Opt.Eng.45,117004:1–7(2006).
36.N.T.Shaked,B.Katz,and J.Rosen,“Fluorescence multicolor
hologram recorded by using a macrolens array,”Opt.Lett.33, 1461–1463(2008).
37.N.T.Shaked and J.Rosen,“Modified Fresnel computer-
generated hologram directly recorded by multiple-viewpoint projections,”Appl.Opt.47,D21–D27(2008).
38.N.T.Shaked and J.Rosen,“Multiple-viewpoint projection
holograms synthesized by spatially incoherent correlation with broadband functions,”J.Opt.Soc.Am.A25,2129–2138 (2008).
39.D.Abookasis and J.Rosen,“Digital correlation holograms im-
plemented on a joint transform correlator,”https://www.doczj.com/doc/6113718963.html,mun.
225,31–37(2003).
40.B.Javidi and A.Sergent,“Fully phase encoded key and bio-
metrics for security verification,”Opt.Eng.36,935–942 (1997).
41.D.Abookasis,A.Batikoff,H.Famini,and J.Rosen,“Perfor-
mance comparison of iterative algorithms for generating digi-tal correlation holograms used in optical security systems,”
Appl.Opt.45,4617–4624(2006).
42.D.C.Youla and H.Webb,“Image restoration by the method of
convex projections:part1—theory,”IEEE Trans.Med.Imag-ing1,81–94(1982).
43.J.R.Fienup,“Phase-retrieval algorithm:a comparison,”Appl.
Opt.21,2758–2769(1982).
44.H.Stark,Image Recovery:Theory and Application(Academic,
1987),pp.29–78and277–320.
45.J.Rosen and J.Shamir,“Application of the projection-onto-
constraint-sets algorithm for optical pattern recognition,”
Opt.Lett.16,752–754(1991).
https://www.doczj.com/doc/6113718963.html,kowicz,Principles of Fluorescence Spectroscopy,3rd ed.
(Springer,2006),Chap.1.
47.T.Vo-Dinh,ed.,Biomedical Photonics Handbook(CRC Press,
2003),Chap.3.5.
48.N.T.Shaked,Y.Yitzhaky,and J.Rosen“Incoherent holo-
graphic imaging through thin turbulent media,”https://www.doczj.com/doc/6113718963.html,-mun.282,1546–1550(2009).
49.T.Vo-Dinh,ed.,Biomedical Photonics Handbook(CRC Press,
2003),Chaps.13and16.
50.J.C.Hebden,S.R.Arridge,and D.T.Delpy,“Optical imaging
in medicine:I.Experimental techniques,”Phys.Med.Biol.42, 825–840(1997).
51.J.Rosen and D.Abookasis,“Seeing through biological tissues
using the fly eye principle,”Opt.Express11,3605–3611 (2003).
52.J.Rosen and D.Abookasis,“Noninvasive optical imaging by
speckle ensemble,”Opt.Lett.29,253–255(2004).
53.J.Rosen and D.Abookasis,“NOISE2imaging system:Seeing
through scattering tissue by correlation with a point,”Opt.
Lett.29,253(2004).
54.D.Abookasis and J.Rosen,“Stereoscopic imaging through
scattering media,”Opt.Lett.31,724–726(2006).
1December2009/Vol.48,No.34/APPLIED OPTICS H135
55.I.Moon and B.Javidi,“Three-dimensional visualization of ob-
jects in scattering medium by use of computational integral imaging,”Opt.Express16,13080–13089(2008).
56.O.Shacham,O.Haik,and Y.Yitzhaky,“Blind restoration
of atmospherically degraded images by automatic best step edge detection,”Pattern Recogn.Lett.28,2094–2103 (2007).
57.N.T.Shaked,G.Segev,and J.Rosen,“Three-dimensional ob-
ject recognition using a quasi-correlator invariant to imaging distances,”Opt.Express16,17148–17153(2008).
58.R.Bamler and J.Hofer-Alfeis,“Three-and four dimensional
filter operations by coherent optics,”Opt.Acta29,747–757 (1982).
59.J.Rosen,“Three-dimensional optical Fourier transform and
correlation,”Opt.Lett.22,964–966(1997).
60.J.Rosen,“Three-dimensional electro-optical correlation,”
J.Opt.Soc.Am.A15,430–436(1998).
61.J.Rosen,“Three-dimensional joint transform correlator,”
Appl.Opt.37,7538–7544(1998).
62.Y.Li and J.Rosen,“Three-dimensional pattern recognition
with a single two-dimensional synthetic reference function,”
Appl.Opt.39,1251–1259(2000).
63.Y.Li and J.Rosen,“Three-dimensional correlator with general
complex filters,”Appl.Opt.39,6561–6572(2000).64.T.-C.Poon and T.Kim,“Optical image recognition of three di-
mensional objects,”Appl.Opt.38,370–381(1999).
65.J.J.Esteve-Taboada,D.Mas,and J.Garcia,“Three dimen-
sional object recognition by Fourier transform profilometry,”
Appl.Opt.38,4760–4765(1999).
66.Y.Li and J.Rosen,“Object recognition using three-
dimensional optical quasi-correlation,”J.Opt.Soc.Am.A19, 1755–1762(2002).
67.B.Javidi,R.Ponce-Díaz,and S.-H.Hong,“Three-
dimensional recognition of occluded objects by using com-putational integral imaging,”Opt.Lett.31,1106–1108(2006).
68.J.-S.Park, D.-C.Hwang, D.-H.Shin,and E.-S.Kim,
“Resolution-enhanced three-dimensional image correlator using computationally reconstructed integral images,”Opt.
Commun.276,72–79(2007).
69.D.-H.Shin and H.Yoo,“Scale-variant magnification for com-
putational integral imaging and its application to3D object correlator,”Opt.Express16,8855–8867(2008).
70.Y.Li and J.Rosen,“Scale-invariant recognition of three-
dimensional objects using quasi-correlator,”Appl.Opt.42, 811–819(2003).
71.J.-H.Park,J.Kim,and B.Lee,“Three-dimensional optical cor-
relator using a subimage array,”Opt.Express13,5116–5126 (2005).
H136APPLIED OPTICS/Vol.48,No.34/1December2009
人教版七年级下 Unit 1 Can you play the guitar? 1. n.吉他 _____________ 2. v.唱歌_____________ 3. v.游泳____________ 4. v.跳舞；舞蹈____________ 5. v.画_________________ 6. n.国际象棋__________________ 7. 下国际象棋__________________ 8. v.说；说话____________________ 9. 说英语______________ 10. v.参加；加入________________ 11. n.俱乐部；社团____________________ 12. 擅长于……________________________ 13. v.讲述；告诉___________________ 14. n故事；小说_________________ 15. v.写作；写字__________________ 16. n.演出；节目 v.给……看；展示________ 17. .或者 ____________________ 18. v. n说话；谈话___________________ 19. 跟……说 ___________________ 20. n.（中国）功夫___________________ 21. n.鼓 ____________________ 22. 敲鼓____________________ 23. n.钢琴_____________________ 24. 弹钢琴________________________ 25. n.小提琴______________________ 26 .拉小提琴_______________________ 27. adv也；而且_____________________ 人；人们 _____________________ 29. n 家；活动本部.adv 到家；在家__________ 30. 善于应付……的；对……有办法_________ 31. v.使成为；制造_________________ 32. 结交朋友____________________ .在今天___________________ 34. 在某方面帮助（某人） _______________ 35.）中心；中央_____________________ 36. n.周末 ______________________ 37. (在)周末___________________ 教；讲授 _______________ 39. n.音乐家 _______________ Unit 2 What time do you go to school
Starter Unit 1 good /gud/ adj 好的 morning /m?:(r)n??/ n 早晨；上午 Good morning 早上好！ hi /ha?/ interj (用于打招呼)嗨；喂 hell o /h?l?u/ interj 你好；喂 afternoon /?ɑ:ft?nu:n//??ft?rnu:n/ n 下午Good afternoon! 下午好！ evening /i:vn??/ n 晚上；傍晚 Good evening! 晚上好！ how /ha?/ adv 怎样；如何 are /ɑ: (r)//?: (r)/ v 是 you /ju:/ pron 你；你们 How are you? 你好吗？ I /ai/ pron 我 am /?m/ v 是 fine /fa?n/ adj 健康的；美好的 thanks /θ??ks/ interj / n. 感谢；谢谢OK /??kei/ interj / adv 好；可以 HB /?e?t?bi:/ (铅笔芯)硬黑 CD /?si: di:/ 光盘；激光唱片 BBC /?bi:bi: si:/ 英国广播公司 Alice /?l?s/ 艾丽丝(女名) Bob /b?b//bɑ:b/ 鲍勃(男名) Cindy /s?ndi/ 辛迪(女名) Dale /de?l/ 戴尔(男名) Eric /er?k/ 埃里克(男名) Frank /fr??k/ 弗兰克(男名) Grace /gre?s/ 格雷丝(女名) Helen /hel?n/ 海伦(女名) Starter Unit 2 what /w?t//wɑ:t/ pron / adj 什么 is /?z/ v 是 this /e?s/ pron 这；这个 in /?n/ prep (表示使用语言、材料等)用；以 English /??gl??/ n / adj 英语/ 英格兰的；英语的 in English 用英语 map /m?p/ n 地图 cup /k?p/ n 杯子 ruler /ru:l?(r)/ n 尺；直尺 pen /pen/ n 笔；钢笔 orange /?r?nd?//?:r?nd?/ n 橙子 jacket /d??k?t/ n 夹克衫；短上衣 key /ki:/ n 钥匙 quilt /kw?lt/ n 被子；床罩 it /?t/ pron 它 a / an /ei; ?//?n; ?n/ art 用于单数可数名词前，表示未曾提到的一(人、事、物) that /e?t/ pron 那；那个 spell /spel/ v 用字母拼；拼写
新人教版七年级英语上册单词及短语Unit1 https://www.doczj.com/doc/6113718963.html,名称;名字n 2.nice好的；令人愉快的adj. 3.to用于与动词原形一起构成动词不定式 4.meet遇见；相逢v. 5.too也;太;有adv 6.your 你的；你们的pron. 7.Ms.女士 8.his他的pron. 9.and和；又；而且conj. 10.her她的pron. 11.yes是的；可以interj 12.she她pron 13.he他pron 14.no不；没有；不是adv.& adj. 15.not不；没有adv 16.zero零num. 17.one 一num 18. two 二num. 19.three三num. 20.four 四num. 21.five 五num 22.six 六num 23. seven 七num. 24.eight 八num. 25. nine 九num. 26.telephone 电话；电话机 n. 27.number 号码；数字n. 28. phone 电话；电话机n. 29.telephone number/ phone number 电话号码 30. first 第一adj. 31. first name 名字 32. last 最后的；末尾的adj. 33. last name 姓 34.friend朋友n 35.China中国 36.middle中间的adj；中 间 n 37.school学校n 38.middle school初中；中学 Unit2 1. sister 姐；妹n. 2. mother 妈妈；母亲n. 3. father 爸爸；父亲 n. 4. parent 父亲或母亲n. 5. brother 兄；弟n. 6. grandmother （外）祖母；奶奶；外婆；姥姥n. 7. grandfather （外）祖父；爷爷；外公；姥爷n. 8. grandparent 祖父（母）；外祖父（母）n. 9.fanily 家；家庭 n 10.those 那些pron. 11.who 谁；什么人pron 12.oh 哦；啊interj 13. these 这些 pron 14.they 他（她、它）们pron 15.well 嗯；好吧interj 16.have 经受；经历v 17.day 一天；一日；白天n. 18.Have a good day （表示祝 愿）过得愉快 19.bye 再见interj （=goodbye) 20. son 儿子 n. 21. cousin 堂兄（弟、姊、 妹）;表兄（弟、姊、妹n. 22.grandpa （外）祖父；爷 爷；外公；姥爷n. 23.mom （=mum）妈妈n 24. aunt 姨母；姑母；伯母； 婶母；舅母 n. 25.grandma （外）祖母； 奶奶；外婆；姥姥n. 26.dad 爸爸n 27. uncle 叔父；伯父；舅父； 姨父；姑父 n. 28.daughter 女儿 n. 29.here （用以介绍某人或 某物）这就是；在这里adv. 30.photo 照片n. 31.of 属于（某人或某物）； 关于（某人或某物）prep 32.next 下一个（的）；接下 来（的）n 33.picture 照片；图画 n. 34. girl 女孩n. 35.dog 狗n Unit3 1.pencil 铅笔n 2.book 书n 3.eraser 橡皮n
新目标人教版七年级下册英语单词表 Unit 1 Can you play the guitar? 1. guitar [ɡ？ 'tɑ?r] n.吉他2. join [d???n] v.参加；加入 3. dance [dɑ?ns][d?ns] v.跳舞；舞蹈 4. swim [sw?m] v.游泳 5. sing [s??]v.唱；唱歌 6. chess [t?es] n.国际象棋 7. paint [peint][pent] v.画画 8. speak [spi:k][spik] v.说；说话 9. piano ['pjɑ？ n??] n.钢琴 10. drum [dr?m] n.喇叭 11. violin [?va??'l?n] n.小提琴12. or [??r] conj.或者 13. musician [mju'z??n] n.音乐家 14. show [???] n.演出;表演v.展示；给..看 15.draw [dr??]v.画 16.story ['st??ri] 故事、事迹、小说 17.tell [tel] v.告诉；讲述 18.write [rait] v.书写 19.talk [t??k] 谈话、谈论 20.also ['??ls??] 也；亦；而且adv. 21.people ['pi?pl]人；人民n. 22.center ['s?nt?]中央、中心 23.home [h??m] adv.家 24.today [t?'de?] n.& adv.今天；今日
25.make [meik] 使、促使、迫使 26.weekend ['wi?kend]n.周末；星期六和星期日 27teach [ti?t?] 教、讲授28 club [kl?b] 社团；俱乐部n. 29 show [???] n.演出;表演v.展示；给..看 Unit 2 What time do you go to school? 1up [?p] prep.向上 2dressed [drest] adj.打扮好的；穿着衣服的 动词dress的过去式和过去分词. 3brush [br??] v.刷 4showe['?a??(r)]v.淋浴;淋浴器 5usually ['ju??u?li] adv.通常 6forty ['f??rti] num.四十7never ['nev?(r)] adv.永不；绝不；从不；未曾 8early ['??li] adv.早adj.早 9fifty ['f?fti] num.五十 10job [d?ɑ?b]n.工作；零工；任务；职位 13o'clock(=of the clock) adv.…点钟(只用于正点) 14.station ['ste??n] n.电视台；车站 15.funny ['f?ni] adj奇怪的滑稽好笑的 16.exercise ['eks?rsa?z] v.n 锻炼；练习 17.group [ɡru?p] n.组群 18.take a shower淋浴；洗澡 19.work [w??rk] n.& v.工作
七年级英语单词表 Starter Unit 1 good /gud/ adj. 好的 morning /'m?:ni?/ n. 早晨；上午 Good morning! 早上好！ hi /hai/ interj. (用于打招呼)嗨；喂 hello /h?'l?u/ interj. 你好；喂 afternoon /,a:ft?'nu:n/ n. 下午 Good afternoon! 下午好！ evening /'i:vni?/ n. 晚上；傍晚 Good evening! 晚上好！ how /hau/ adv. 怎样；如何 are /a:/ v. 是 you /ju:/ pron. 你；你们 How are you? 你好吗？ I /ai/ pron. 我 am /?m/ v. 是 fine /fain/ adj. 健康的；美好的 thanks /θ??ks/ interj.&n. 感谢；谢谢 OK /?u'kei/ interj.& adv. 好；可以 Starter Unit 2 what /w?t/ pron.&adj. 什么 is /iz/ v. 是 this /eis/ pron. 这；这个 in /in/ prep. (表示使用语言、材料等)用；以English /'i?gli?/ n. 英语adj. 英格兰的；英语的 in English 用英语 map /m?p/ n. 地图 cup /k?p/ n. 杯子 ruler /'ru:l?/ n. 尺；直尺 pen /pen/ n. 笔；钢笔 orange /'?rind?/ n. 橙子 jacket /'d??kit/ n. 夹克衫；短上衣 key /ki:/ n. 钥匙 quilt /kwilt/ n. 被子；床罩 it /it/ pron. 它 a /?/ art. (用于单数可数名词前)一(人、事、物) that /e?t/ pron. 那；那个spell /spel/ v. 用字母拼；拼写 please /pli:z/ interj. (用于客气地请求或吩咐)请 Starter Unit 3 color /'k?l?/ n. (=colour) 颜色 red /red/ adj.& n. 红色（的） yellow /'jel?u/ adj.& n. 黄色（的） green /gri:n/ adj.& n. 绿色（的） blue /blu:/ adj.& n. 蓝色（的） black /bl?k/ adj.& n. 黑色（的） white /wait/ adj.& n. 白色（的） purple /'p?:pl/ adj.& n. 紫色（的） brown /braun/ adj.& n. 棕色（的）；褐色（的）the /ei; e?/ art. 指已提到或易领会到的人或事 now /nau/ adv. 现在；目前 see /si:/ v. 理解；明白 can /k?n/ modal v. 能；会 say /sei/ v. 说；讲 my /mai/ pron. 我的
2018人教版七年级英语下册单词-中文
吉他 唱歌 游泳 v.跳舞；n.舞蹈 画 国际象棋 下国际象棋 说（某种语言）；说话 说英语 参加；加入 俱乐部；社团 擅长于…… 讲述；告诉 故事；小说 写作；写字 n.演出；节目 v.给……看；展示 或者；也不（用于否定句）说话；交谈跟……说 （中国）功夫 鼓 敲鼓 钢琴 弹钢琴 小提琴 拉小提琴 也；而且 人；人们 n.家；活动本部 adv.到家；在家 善于……的；对……有办法使成为；制造 结交朋友 在今天 在某方面帮助（某人） 中心；中央 周末 （在）周末
v.打扫；弄干净 adj.干净的 行走；步行 散步；走一走 很快地 或者；也（用在否定词组后） 要么……要么……；或者……或者…… 大量；许多 有时 v.有……的味道；品尝 n.味道；滋味 生活；生命 里克（男名） 吉姆（男名） 斯科特（男名）托尼（男名） 火车公共汽车 地铁 乘地铁 v.骑 n.旅程 自行车 骑自行车 六十 七十 八十 九十 一百 分钟 远；远的 千米；公里 新的；刚出现的 每一；每个 每天 （表示方式）乘（交通工具）骑自行车 开车
小汽车；轿车 居住；生活 车站；停止 认为 横过；越过 河；江 许多 村庄；村镇 介于……之间在……和……之间 桥 小船 索道 年；岁 害怕；畏惧 像；怎么样 村民 离开 n.梦想；睡梦 v.做梦真的；符合事实的实现；成为现实 戴夫（男名） 规则；规章 到达 准时 走廊；过道 大厅；礼堂 餐厅 听；倾听 听…… 打架；战斗 抱歉的；难过的；惋惜的adv.在外面 adj.外面的穿；戴 重要的 带来；取来 校服；制服 安静的
camp n 野营；营地 can modal v. 能；可以；会 Canada n 加拿大 can't 词组（=can not） captain n 队长；首领 card n. 卡；卡片；纸牌 Carol 姓名卡罗尔(女名) carrot n. 胡萝卜 case n. 箱；盒；橱 cat n 猫 Cathy 姓名卡西(女名) CD abbr. （=compact disc）激光唱片 center n 中央；中心 central a 中心的；位于中心的 chair n. 椅子 cheap a 廉价的；便宜的 chess n. 国际象棋 chicken n. 鸡；鸡肉 children n 孩子们(child的复数形式) Children's Palace 词组少年宫 China 词组中国 Chinese n. 中文；中国人 Chinese adj. 中国的；中国人的 city n. 城市 class n. 班级；（一节）课 classmate n 同班同学 classroom n 教室 clean a 清洁的；干净的 clean v 清扫；清除 clerk n. （银行、办公室、商店等）职员；办事员clever a 聪明的；机灵的 clock n. 时钟 clothes n. （pl.）衣服；服装 cloudy a 多云的；阴天的 club n. 社团；俱乐部 cold a 寒冷的 collection n. 收藏品；收集物 color n. 色；颜色 colorful a 色彩鲜艳的 come v. 来；来到 comedy n. 喜剧 computer n. 电脑；电子计算机 computer game 词组电子游戏 contest n. 竞争；竞赛；比赛
2013人教版七年级下册英语各单元知识点大归纳 Unit 1 Can you play the guitar? ◆短语归纳 play the guitar 弹吉他play the piano 弹钢琴play the trumpet吹喇叭 play the drums 敲鼓play chess 下象棋speak English 说英语 speak a little English 说一点英语say it in English 用英语说它 join the art club 加入艺术俱乐部join the basketball club加入篮球俱乐部 join the swimming club加入游泳俱乐部what club 什么俱乐部 play the guitar well 弹吉他弹得好be good with sb和某人相处的好 be good for···对······有益处be good at···擅长······ help sb with sth / doing sth帮助某人干某事help kids with swimming帮助孩子们游泳 do Chinese kung fu表演中国功夫be in参加，加入 call sb at + 电话号码给某人打电话拨打···号 have an e-mail address 有电子邮件的地址rock band 摇滚乐队 a little 一点（后接不可数名词）in the music room 在音乐教室里 show sth to sb = show sb sth 把某物给某人看 on the weekend/on weekends 在周末 ◆用法集萃 1. play +棋类/球类下……棋，打……球 2. play the +西洋乐器弹/拉……乐器 3. be good at doing sth.= do well in doing sth. 擅长做某事 4. be good with sb. 和某人相处地好 5. need sb. to do sth. 需要某人做某事 6. can + 动词原形能/会做某事 7. a little + 不可数名词一点儿…… 8. join the …club 加入…俱乐部 9. like to do sth. =love to do sth. 喜欢/喜爱做某事 ◆典句必背 1. Can you draw? Yes, I can. / No, I can’t. 2. What club do you want to join? I want to join the chess club. 3. You can join the English club. 4. Sounds good./That sounds good. 5. I can speak English and I can also play soccer. 6. Please call Mrs. Miller at 555-3721. ◆话题写作 Dear Sir, I want to join your organization (组织) to help kids with sports, music and English. My name is Mike. I am 15 years old. I’m a student in No. 1 Middle school. I can play the guitar well. I can sing many songs. I can swim and speak English well, too. I think I can be good with the kids. I also do well in telling stories. I hope to get your letter soon. Yours, Mike Unit 2 What time do you go to school? ◆短语归纳 1. what time 几点 2. go to school 去上学 3. get up 起床 1
新人教版七年级英语下册单词表|人教版七年级英语单词 新人教版的七年级英语学习需要一些方法、技巧,才能有效地记牢单词,扩大语汇量。下面是小编为大家精心推荐的新人教版七年级英语下册的单词表，希望能够对您有所帮助。 新人教版七年级英语下册单词表：1-4 单元 Unit 1 Can you play the guitar? guitar n. 吉他 sing v.唱 ;唱歌 swim v. 游泳 dance v.跳舞 ;舞蹈 draw v.画 chess n.国际象棋 play chess 下国际象棋 speak v.说; 说话 speak English说英语 join v. 参加 ;加入 club n. 俱乐部 ; 社团 be good at ?擅长于?? tell v. n 讲述 ;告诉 story n 故事 ;小说 write v. 写作 ,写字 show n.演出 ;表演 v.展示 ; or conj. 或者 talk v. n 说话 ;谈话 talk to?跟??说 kungfu n. 功夫 drum n.鼓 play the drums敲鼓 piano n.钢琴 play the piano弹钢琴 violin n. 小提琴 play the violin拉小提琴 also adv 也 ;而且 people n 人 ;人们 home n 家 ,活动本部 .adv 到家 ;在家 be good with ?善于应付??的; 对??有办法 make v.使成为 ;制造 make friends 结交朋友 today adv.在今天 help with sth在某方面帮助 center n 中心 ,中央 weekend. n.周末 on the weekend. 周末 teach v 教 ,讲授
2017人教版七年级上册英语单词表 Starter Unit 1 good /gud/adj. 好的 morning /'m?:ni?/ n. 早晨；上午 Good morning! 早上好！ hi /hai/ interj. (用于打招呼)嗨；喂 hello/h?'l?u/ interj. 你好；喂 afternoon /,a:ft?'nu:n/ n. 下午 Good afternoon! 下午好！ evening /'i:vni?/ n. 晚上；傍晚 Good evening! 晚上好！ how /hau/adv. 怎样；如何 are /a:/v. 是 you /ju:/pron. 你；你们 How are you? 你好吗？ I /ai/pron. 我 am /?m/v. 是 fine/fain/ adj. 健康的；美好的 thanks/θ??ks/ interj.&n. 感谢；谢谢 OK/?u'kei/ interj.& adv. 好；可以 Starter Unit 2 what /w?t/pron.&adj. 什么 is /iz/v. 是 this /?is/pron. 这；这个 in /in/prep. (表示使用语言、材料等)用；以English /'i?gli?/ n. 英语adj. 英格兰的；英语的 in English 用英语 map /m?p/n. 地图 cup /k?p/n. 杯子 ruler /'ru:l?/ n. 尺；直尺 pen /pen/n. 笔；钢笔 orange /'?rind?/ n. 橙子 jacket /'d??kit/ n. 夹克衫；短上衣 key /ki:/n. 钥匙 it /it/pron. 它 a (an) /?/ art.(用于单数可数名词前，表示未曾提到的)一 (人、事、物) that /??t/pron. 那；那个 spell /spel/ v. 用字母拼；拼写 please /pli:z/ interj. (用于客气地请求或吩咐)请 Starter Unit 3 color /'k?l?/ n. (=colour) 颜色 red /red/adj.& n. 红色（的） yellow /'jel?u/ adj.& n. 黄色（的） green /gri:n/ adj.& n. 绿色（的） blue /blu:/ adj.& n. 蓝色（的） black /bl?k/ adj.& n. 黑色（的） white /wait/ adj.& n. 白色（的） purple /'p?:pl/ adj.& n. 紫色（的）
七年级英语单词表StarterUnit1 1.好的 2.早晨；上午 3.早上好！ 4.嗨；喂 5.你好；喂 6.n.下午 7.下午好！ 8.n.晚上；傍晚 9.晚上好！ 10.a dv.怎样；如何 11.v.是 12.p ron.你；你们 13.你好吗？ 14./pron.我 15.v.是 16.a dj.健康的；美好的 17.i nterj.&n.感谢；谢谢 18.i nterj.&adv.好；可以 StarterUnit2 1.pron.&adj.什么 2.v.是 3.pron.这；这个 4.prep.(表示使用语言、材料等) 用；以 5.n.英语adj.英格兰的；英语的 6.用英语 7.n.地图 8.n.杯子 9.n.尺；直尺 10.n.笔；钢笔 11.n.橙子 12.n.夹克衫；短上衣 13.n.钥匙 14.n.被子；床罩 15.p ron.它 16.a rt.(用于单数可数名词前)一 (人、事、物) 17.p ron.那；那个 18.v.用字母拼；拼写 19.i nterj.(用于客气地请求或吩 咐)请 StarterUnit3 1.颜色 2.adj.&n.红色（的）
3.adj.&n.黄色（的） 4.adj.&n.绿色（的） 5.adj.&n.蓝色（的） 6.adj.&n.黑色（的） 7.adj.&n.白色（的） 8.adj.&n.紫色（的） 9.adj.&n.棕色（的）；褐色（的） 10.a rt.指已提到或易领会到的人 或事 11.a dv.现在；目前 12.v.理解；明白 13.m odalv.能；会 14.v.说；讲 15.p ron.我的 Unit1 1.n.名字；名称 2.adj.令人愉快的；宜人的 3.常用于原形动词之前，该动词 为不定式 4.v.遇见；相逢 5.adv.也；又；太 6.pron.你的；你们的 7.(于女子的姓名前，不指明婚 否)女士 8.pron.他的 9.conj.和；又；而 10.p ron,她的 11.i nterj.是的；可以 12.p ron.她 13.p ron.他 14.i nterj.不；没有；不是 15.a dv.不；没有 16.n um.零 17.n um.一 18.n um.二 19.n um.三 20.n um.四 21.n um.五 22.n um.六 23.n um.七 24.n um.八 25.n um.九 26.n.电话；电话机 27.n.号码；数字 28.n.电话；电话机
七年级上册英语单词表 Starter Unit 1 good /g?d/ adj. 好的 morning /'m?:n??/ n. 早晨；上午 Good morning! 早上好！ hi /ha?/ interj. (用于打招呼)嗨；喂 hello /h?'l??/ interj. 你好；喂 afternoon /,ɑ:ft?'nu:n/ n. 下午 Good afternoon! 下午好！ evening /'i:vn??/ n. 晚上；傍晚 Good evening! 晚上好！ how /ha?/ adv. 怎样；如何 are /ɑ:/ v. 是 you /ju:/ pron. 你；你们 How are you? 你好吗？ I /a?/ pron. 我 am /?m/ v. 是 fine /fa?n/ adj. 健康的；美好的 thanks /θ??ks/ interj.&n. 感谢；谢谢 OK /??'ke?/ interj.& adv. 好；可以 Starter Unit 2 what /w?t/ pron.&adj. 什么 is /?z/ v. 是 this /e?s/ pron. 这；这个 in /?n/ prep. (表示使用语言、材料等)用；以English /'??gl??/ n. 英语adj. 英格兰的；英语的in English 用英语 map /m?p/ n. 地图 cup /k?p/ n. 杯子 ruler /'ru:l?/ n. 尺；直尺 pen /pen/ n. 笔；钢笔 orange /'?r?nd?/ n. 橙子 jacket /'d??k?t/ n. 夹克衫；短上衣 key /ki:/ n. 钥匙 quilt /kw?lt/ n. 被子；床罩 it /?t/ pron. 它 a /?/ art. (用于单数可数名词前)一(人、事、物) that /e?t/ pron. 那；那个 spell /spel/ v. 用字母拼；拼写 please /pli:z/ interj. (用于客气地请求或吩咐)请Starter Unit 3 color /'k?l?/ n. (=colour) 颜色 red /red/ adj.& n. 红色（的） yellow /'jel??/ adj.& n. 黄色（的） green /gri:n/ adj.& n. 绿色（的） blue /blu:/ adj.& n. 蓝色（的）black /bl?k/ adj.& n. 黑色（的） white /wa?t/ adj.& n. 白色（的） purple /'p?:pl/ adj.& n. 紫色（的） brown /bra?n/ adj.& n. 棕色（的）；褐色（的） the /e?; e?/ art. 指已提到或易领会到的人或事 now /na?/ adv. 现在；目前 see /si:/ v. 理解；明白 can /k?n/ modal v. 能；会 say /se?/ v. 说；讲 my /ma?/ pron. 我的 Unit 1 name /ne?m/ n. 名字；名称 nice /na?s/ adj. 令人愉快的；宜人的 to /tu:/ 常用于原形动词之前，该动词为不定式meet /mi:t/ v. 遇见；相逢 too /tu:/ adv. 也；又；太 your /j?:/ pron. 你的；你们的 Ms. /m?z/ (于女子的姓名前，不指明婚否)女士 his /h?z/ pron. 他的 and /?nd/ conj. 和；又；而 her /h?:/ pron, 她的 yes /jes/ interj. 是的；可以 she /?i:/ pron. 她 he /hi:/ pron. 他 no /n??/ interj. 不；没有；不是 not /n?t/ adv. 不；没有 zero /'z??r??/ num. 零 one /w?n/ num. 一 two /tu:/ num. 二 three /θri:/ num. 三 four /f?:/ num. 四 five /fa?v/ num. 五 six /s?ks/ num. 六 seven /'sevn/ num. 七 e?ght /e?t/ num. 八 nine /na?n/ num. 九 telephone /'tel?f??n/ n. 电话；电话机 number /'n?mb?/ n. 号码；数字 phone /f??n/ n. 电话；电话机 telephone/phone number 电话号码 first /f?:st/ adj. 第一 first name 名字 last /lɑ:st/ adj. 最后的；末尾的 last name 姓 friend /frend/ n. 朋友 China /'t?a?n?/ 中国 middle /'m?dl/ adj. 中间的；中间 school /sku:l/ n. 学校 middle school 中学；初中 - 1 -
新人教版七年级英语单词表 Starter Unit 1 it pron.它 good adj.好的that pron.那;那个 morning n.早晨;上午spell v.用字母拼;拼写 int.(用于客气地请求或吩咐) Good morning ! 早上好！please 请 hi int.(用于打招呼)嗨;喂NBA (美国)全国篮球协会 hello int.你好;喂P＝parking 停车场;停车位 afternoon n.下午kg=kilogram 千克;公斤 Good a fternoon ! 中午好！ evening n.晚上;黄昏 Starter Unit 3 Good evening ! 晚上好！ color how adv.怎样;如何 n.颜色 (=colour) are v.是red adj.＆n.红色(的) you pron.你;你们yellow adj.＆n.黄色(的) How are you ? 你好吗？green adj.＆n.绿色(的) I pron.我blue adj.＆n.蓝色(的) am v.是black adj.＆n.黑色(的) fine adj.健康的;美好的white adj.＆n.白色(的) thanks int.＆n.感谢;谢谢purple adj.＆n.紫色(的)
OK int.＆adv.好;可以brown adj.＆n.棕色(的);褐色(的) art.指已提到或易领会到的人HB (铅笔芯)硬黑the 或事物 CD 光盘;激光唱片now adv.现在;目前 BBC 英国广播公司see v.理解;明白 Starter Unit 2 can modal v.能;会 what pron.&adj.什么say v.说;讲 is v.是my pron.我的 this pron.这;这个S (尤指服装的尺码)小号的prep.(表示使用语言、材料等) M (尤指服装的尺码)中号的 in 用;以 n.英语; adj.英格兰的;英语 English L (尤指服装的尺码)大号的的 in English 用英语UFO 不明飞行物 map n.地图CCTV 中国中央电视台 cup n.杯子 七年级上 Unit 1 ruler n尺;直尺 pen n.笔;钢笔name n.名字;名称 orange n. 橘子nice adj.令人愉快的;宜人的jacket n.夹克衫;短上衣meet v.遇见;相逢 key n.钥匙too adv.也;又;太
. 七年级英语单词表 Starter Unit 1 good /gud/ adj. 好的 morning /'m?:ni?/ n. 早晨；上午 Good morning! 早上好！ hi /hai/ interj. (用于打招呼)嗨；喂 hello /h?'l?u/ interj. 你好；喂 afternoon /,a:ft?'nu:n/ n. 下午 Good afternoon! 下午好！ evening /'i:vni?/ n. 晚上；傍晚 Good evening! 晚上好！ how /hau/ adv. 怎样；如何 are /a:/ v. 是 you /ju:/ pron. 你；你们 How are you? 你好吗？ I /ai/ pron. 我 am /?m/ v. 是 fine /fain/ adj. 健康的；美好的 thanks /θ??ks/ interj.&n. 感谢；谢谢 OK /?u'kei/ interj.& adv. 好；可以 Starter Unit 2 what /w?t/ pron.&adj. 什么 is /iz/ v. 是 this /eis/ pron. 这；这个 in /in/ prep. (表示使用语言、材料等)用；以English /'i?gli?/ n. 英语adj. 英格兰的；英语的in English 用英语 map /m?p/ n. 地图 cup /k?p/ n. 杯子 ruler /'ru:l?/ n. 尺；直尺 pen /pen/ n. 笔；钢笔 orange /'?rind?/ n. 橙子 jacket /'d??kit/ n. 夹克衫；短上衣 key /ki:/ n. 钥匙 quilt /kwilt/ n. 被子；床罩 it /it/ pron. 它 a /?/ art. (用于单数可数名词前)一(人、事、物) that /e?t/ pron. 那；那个 spell /spel/ v. 用字母拼；拼写 please /pli:z/ interj. (用于客气地请求或吩咐)请 Starter Unit 3 color /'k?l?/ n. (=colour) 颜色 red /red/ adj.& n. 红色（的） yellow /'jel?u/ adj.& n. 黄色（的） green /gri:n/ adj.& n. 绿色（的） blue /blu:/ adj.& n. 蓝色（的） black /bl?k/ adj.& n. 黑色（的） white /wait/ adj.& n. 白色（的） purple /'p?:pl/ adj.& n. 紫色（的） brown /braun/ adj.& n. 棕色（的）；褐色（的）the /ei; e?/ art. 指已提到或易领会到的人或事now /nau/ adv. 现在；目前 see /si:/ v. 理解；明白 can /k?n/ modal v. 能；会 say /sei/ v. 说；讲 my /mai/ pron. 我的
2017人教版七年级上册英语单词表Starter Un it 1 good /gud/adj. 好的 morning/'m:n i/ n. 早晨；上午 Good morning! 早上好！ hi /hai/ interj.（用于打招呼）嗨；喂 hello/h'lu/i nterj. 你好；喂 after noon /,a:ft' nu: n/ n. 下午 Good afternoo n! 下午好！ evening /'i:v ni/ n. 晚上；傍晚 Good evening! 晚上好！ how /hau/adv.怎样；如何 are /a:/v. 是 you /ju:/pro n. 你；你们 How are you 你好吗 I /ai/pro n. 我 am /m/v.是 fin e/fai n/adj. 健康的；美好的 OK/u'kei/ i nterj. & adv. 好；可以Starter Unit 2 what /wt/pr on.& adj. 什么 is /iz/v. 是 this /is/pr on. 这；这个 in /i n/prep.（表示使用语言、材料等）用；以 En glish /'igli/ n. 英语adj. 英格兰的；英语的 in En glish 用英语 map /mp/n.地图 cup /kp/n. 杯子 ruler /'ru:l/ n. 尺；直尺 pen /pe n/n. 笔；钢笔 orange /'ri nd/ n. 橙子 jacket /'dkit/ n. 夹克衫；短上衣 key /ki:/n. 钥匙 it /it/pro n. 它 a （an）用于单数可数名词前，表示未曾提到的）一（人、 事、物）
英语（人教版）七年级上册 Starter Unit1 good adj.好的 morning n.早晨；上午 Good morning!早上好！ hi interj.(用于打招呼)嗨；喂 hello interj.你好；喂 afternoon n.下午 Good afternoon!下午好！ evening n.晚上；傍晚 Good evening!晚上好！ how adv.怎样；如何 are v.是 you pron.你；你们 How are you?你好吗？ I pron.我 am v.是 fine adj.健康的；美好的 thanks interj. n.感谢；谢谢 OK interj. adv.好；可以 HB（铅笔芯）硬黑 CD光盘；激光唱片 BBC英国广播公司 Starter Unit2 what pron. adj.什么 is v.是 this pron.这；这个 in prep.（表示使用语言、材料等）用；以English n.英语adj.英格兰的；英语的 In English用英语 map n.地图 cup n.杯子 rule n.尺；直尺 pen n.笔；钢笔 orange n.橙子 jacket n.夹克衫；短上衣 key n.钥匙 quilt n.被子；床罩 it pron.它 a art.一(人、事、物）
that pron.那；那个 spell v.用字母拼；拼写 please interj.请 NBA（美国）全国篮球联赛 P停车场；停车位 kg n.千克；公斤 Starter Unit3 color n.颜色 red adj. n.红色（的） yellow adj. n.黄色（的） green adj. n.绿色（的） blue adj. n.蓝色（的） black adj. n.黑色（的） white adj. n.白色（的） purple adj. n.紫色（的） brown adj. n.褐色（的）；棕色（的） the art.指已被提到或易领会到的人或事物now adv.现在；目前 see v.理解；明白 can modal v.能；会 say v.说；讲 my pron.我的 S（尤指服装的尺码）小号的 M（尤指服装的尺码）中号的 L（尤指服装的尺码）大号的 UFO不明飞行物 CCTV中国中央电视台 Unit1 name n.名字；名称 nice adj.令人愉快的；宜人的 to常用于原形动词之前，表示该动词为不 定式 meet v.遇见；相逢 too adv.也；又；太 your pron.你的；你们的 Ms.n.(不指名婚否)女士 his pron.他的 and conj.和；又；而 her pron.她的 yes interj.是的；可以 she pron.她