Photoconductance Quantization in a Single-Photon Detector
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基于K均值聚类的图割医学图像分割算法
基于K 均值聚类的图割医学图像分割算法吴永芳，杨 鑫，徐 敏，张 星(中国科学院自动化研究所复杂系统与智能科学重点实验室，北京 100190)摘 要：图割是一种同时基于区域和边界的交互式图像分割算法。
传统的基于高斯混合模型的图割具有时间慢和描述组织中灰度分布不准确的缺点。
为此，提出一种基于K 均值聚类的图割算法。
通过用改进的图割来分割仿体的和真实的脑部核磁共振图像，显示出该方法的有效性。
该方法不但能提高图割在分割时的速度，在有噪音和灰度不均匀的图像上也能在较短的时间内得到更准确且鲁棒的结果。
关键词：图像分割；图割；K 均值聚类；脑部核磁共振图像Graph Cuts Medical Image Segmentation AlgorithmBased on K-means ClusteringWU Yong-fang, YANG Xin, XU Min, ZHANG Xing(Key Laboratory of Complex Systems and Intelligence Science, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China) 【Abstract 】Graph cuts is an interactive segmentation algorithm based on boundary and region properties of objects in images. The region term in conventional graph cuts is based on Gaussian Mixture Model(GMM). However, it is not only a slow process, but sometimes it can’t describe the distribution of pixels in objects precisely. This paper proposes an improved algorithm based on K-means clustering graph cuts. Its evaluation is performed using both phantoms and real Magnetic Resonance Imaging(MRI) of brain, the effectiveness and efficiency of the proposed algorithm are showed. And in particular, an accurate and robust results in segmenting images with noise and intensity non-uniformity with a low computational cost can be achieved.【Key words 】image segmentation; graph cuts; K-means clustering; Magnetic Resonance Imaging(MRI) of brain DOI: 10.3969/j.issn.1000-3428.2011.05.079计 算 机 工 程 Computer Engineering 第37卷 第5期V ol.37 No.5 2011年3月March 2011·图形图像处理· 文章编号：1000—3428(2011)05—0232—03文献标识码：A中图分类号：TP391.411 概述图像分割是在计算机视觉中图像配准和图像可视化的基础，随着各种医学影像(如CT 、MRI 、Ultrasound)在临床中的出现及广泛应用，医学图像分割也成为了制约医学图像普及的一个非常有挑战性的问题[1]。
10物理全息照相
近代物理实验——全息照相讲义
附：
全息干板说明
全息干板是用极微细颗粒卤化银明胶乳剂涂布在玻璃板上面制成，它具有极高的反差和解相力，用于记 录全息图像（干涉条纹） 。使用各种型号的全息干板时，应注意在其规定的安全灯下操作，并注意正确曝光、 冲洗加工。开封及整个使用过程都应在最清洁的条件下进行，否则影响使用效果。
O(x,y)=A0(x,y)ei0(x,y) R(x,y)=Ar(x,y) eir(x,y)
式中 A(x,y)和(x,y)分别表示点(x,y)处的振幅和位相。由于它们系相干光束，根据光的干涉原理，底片上 光的强度 I 是它们合振幅的平方：
I(x,y)=|O+R|2=|O|2+|R|2+RO*+R*O =A02+Ar2+A0Arei(0-r)+ A0Are-i(0-r) =A02+Ar2+A0Arcos(0-r)
5
09 物理专业用
近代物理实验——全息照相讲义
思考题
1、 全息照相与普通照相有什么本质区别？—预习回答 2、 全息照相实验过程中有哪些注意事项？—预习回答 3、 物光和参考光光程要尽量相等，其目的是什么？—预习回答 4、 物光与参考光之夹角为什么不能过大而应尽量放小？ 5、 为什么全息图片有一些破损时还能再现原物完整的像？ 6、 在观察全息照片的真像（虚像）时，能否尝试用手去触及再现景物？而当你的手移近或远离再现景物时， 你能否据此来判断像的位置、大小及深度？
D-19 显影液配方
o 1、蒸馏水（约 50 C） 2、米吐尔（显影剂） 3、无水亚硫酸钠（保护剂） 4、对苯二酚（显影剂）
500ml 2克 90 克 8克
5、无水碳酸钠（显影剂） 48 克 6、溴化钾（抑制剂） 5克 7、加蒸馏水至 1000ml
光子学技术在光学图像处理中的图像增强与特征提取技术分享
光子学技术在光学图像处理中的图像增强与特征提取技术分享光子学技术在光学图像处理中的应用逐渐得到了广泛关注。
光学图像处理是指通过光学仪器或技术对采集的光学图像进行处理和优化的过程。
其中，图像增强和特征提取是两个重要的方面。
光子学技术的应用使得图像处理技术在这些方向上取得了显著的进展。
图像增强是指通过对原始图像进行处理，使目标特征在图像中更加明显可见的过程。
光子学技术在图像增强中扮演了重要的角色。
例如，光子学技术中的激光器和探测器能够提供高质量、高分辨率的成像。
激光器可以提供更加明亮和清晰的图像，而探测器能够接收到更多的光信号，并将其转化为电信号，从而增强图像的清晰度和对比度。
此外，光子学技术还可用于光学图像处理中的滤波和去噪。
滤波是通过选择性地传递或抑制特定频率的光信号来改善图像质量。
光子学技术提供了一种高效且精确的方法来实现滤波操作，从而去除图像中的噪声和干扰，使得目标特征更加清晰可见。
特征提取是光学图像处理的另一个重要方向，它旨在从图像中提取出具有代表性的特征。
光子学技术在特征提取中的应用主要涉及到光学传感器和光纤传感器。
光传感器能够测量光的吸收、散射、反射、透射等属性，通过对这些属性进行分析，可以提取出图像中的各种特征。
光纤传感器则利用光纤的传输和传感特性，实时监测目标物体的形状、温度、压力等参数，并将其转化为图像特征。
光子学技术在图像增强和特征提取中的应用不仅仅局限于传统的光学图像采集与处理，还延伸到了现代计算机视觉和机器学习领域。
例如，利用光子学技术可以实现三维图像重建和识别。
通过使用光学传感器和光纤传感器获取的数据，可以实时生成物体的三维结构，并利用计算机视觉和机器学习算法对其进行分析和识别。
此外，还有一些光子学技术的创新应用，如光学数字图像处理、光学相干断层扫描技术等，也在图像增强和特征提取中发挥着重要作用。
例如，光学数字图像处理利用光子学技术对数字图像进行处理和改善，通过增强图像的对比度、清晰度和细节，提取出图像中的特征。
量子力学英文名词
probability density probability wave normalizing condition Schrödinger equation stationary state stationary Schrödinger equation
势阱
对应原理
隧道效应
能量量子化
Paulaser 泡利不相容原理 激光 自发辐射 受激辐射 氦氖激光器 红宝石激光器
He-Ne laser
Pfund series Bohr quantization condition Bohr hydrogen atom Bohr frequency condition Bohr radius energy level
energy quantum photoelectric effect photo electron photocurrent cutoff potential difference red-limit wave-particle dualism
康普顿效应 康普顿散射 康普顿波长 反冲电子 莱曼系 帕邢系 布拉开系
主量子数
角动量量子化
potential well
correspondence principle
tunneling effect
energy quantization
principal quantum number
angular quantization
角量子数 空间量子化 磁量子数 电子自旋 自旋量子数 自旋磁量子数
Stefan-Boltzmann law Stefan constant Wien displacement law Rayleigh-Jens formula Planck radiation formula Planck constant
半导体材料的锁相载流子辐射成像
半导体材料的锁相载流子辐射成像下载提示：该文档是本店铺精心编制而成的，希望大家下载后，能够帮助大家解决实际问题。
文档下载后可定制修改，请根据实际需要进行调整和使用，谢谢!本店铺为大家提供各种类型的实用资料，如教育随笔、日记赏析、句子摘抄、古诗大全、经典美文、话题作文、工作总结、词语解析、文案摘录、其他资料等等，想了解不同资料格式和写法，敬请关注!Download tips: This document is carefully compiled by this editor. I hope that after you download it, it can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you! In addition, this shop provides you with various types of practical materials, such as educational essays, diary appreciation, sentence excerpts, ancient poems, classic articles, topic composition, work summary, word parsing, copy excerpts, other materials and so on, want to know different data formats and writing methods, please pay attention!半导体材料的锁相载流子辐射成像在现代科技领域，半导体材料一直扮演着至关重要的角色。
Modern Application of mooc课后章节答案期末考试题库2023年
Modern Application of Optoelectronic Technology_南京邮电大学中国大学mooc课后章节答案期末考试题库2023年1.Reconstructive spectrometer is based on compressive sensing theory.参考答案:正确2.Photoconductive detector gain depends on the difference of electron andhole drift speed参考答案:正确3.As tandem structure can increase solar cell efficiency, so we can add as manycells as possible to increase the overall absorption and energy conversionefficiency.参考答案:错误4.The solar cell performance can be degraded by参考答案:Series resistance_Defects in semiconductors_Shunt resistance5.The optical transition in silicon devices is usually indirect参考答案:正确6.Write the bandgap (300k) of silicon _______ eV.参考答案:1.117.The commercial solar cell panels are still dominated by silicon photovoltaics.参考答案:正确D means __________________________参考答案:charge coupled device9._____________________are the study and application of _________________ devices andsystems that source, detect and control ______________.参考答案:Optoelectronics, electronic, photon##%_YZPRLFH_%##Optoelectronics, electronic, light10.Which of the following factors affect the LED output spectrum？参考答案:Operation temperature_Semiconductor bandgap_Dopingconcentration_Applied voltage/current11.Conventional spectrometers used in laboratories are参考答案:Based on dispersive optics_High resolution12.Some typical research results show that graphene hybrid photodetectors can参考答案:Cover a wide detection bandwidth from UV to MIR._Have highresponsivity_Use both planar and vertical heterostructures._Have high detectivity13.The equation to express photoelastic effect is【图片】, which means therefractive index changes with strain参考答案:正确14.What are the four typical layers of optical fibers?____________,___________,____________,_____________.参考答案:core, cladding, protective polymeric coating, buffer tube15.Second harmonic generation happens when an intense light beam offrequency ω passing through an appropriate crystal (e.g., quartz) generates a light beam of half the frequency, 1/2ω参考答案:错误16.The two regimes in acousto-optic modulators are Raman-Nath regimeand___________参考答案:Bragg regime17.Optically anisotropic crystals are called __________ because an incident lightbeam may be doubly refracted. There is also a special direction in abirefringent crystal, called the optic axis.参考答案:birefringent18._____________ is the rotation of the plane of polarization by a substance参考答案:optical activity19.What efficiency is typical of a commercial PERC solar panel?参考答案:20%20.The advantages of perovskite materials include参考答案:High quantum yields_Low-cost_High quantum yields21.Typical optoelectronic process includes参考答案:Light transmission_Light modulation_Light detection_Light generation22.The two operation principles of photonic crystal fibers are ___________________and _____________________.参考答案:total internal reflection, photonic bandgap23.The propagation modes in waveguide can be classified in terms of____________________(TE) mode and ____________________(TM) mode?参考答案:transverse electric field, transverse magnetic field24.Kerr effect can be used to induce birefringence参考答案:正确25.The lattice constant of AlGaAs alloy follows nonlinear mixing rule参考答案:错误26.Which of the following is not a challenge for 2D semiconductor technology?参考答案:Materials choice27.In the space charge region, a high doping concentration results a shortdepletion width参考答案:正确28.CMOS means __________________________参考答案:complementary metal oxide semiconductor29.Photodetectors convert ___________________ to an electrical signal such asa____________________.参考答案:light, voltage or current##%_YZPRLFH_%##photon, voltage or current。
光谱相似性度量方法研究进展
第38卷第8期 2017年8月哈尔滨工程大学学报Journal of Harbin Engineering UniversityVol.38 No. 8Aug. 2017光谱相似性度量方法研究进展赵春晖，田明华，李佳伟(哈尔滨工程大学信息与通信工程学院，黑龙江哈尔滨150001)摘要：为了进一步分析光谱相似性度量在高光谱图像处理中的应用，从距离、投影等角度充分归纳总结了现有二元光谱相似度量方法，并分析讨论了二元光谱相似度量存在的问题。
重点介绍了一种多元光谱相似性测量方法，也称N 维立体光谱角（N-dimensional solid spectral angle, NSSA)方法。
NSSA方法从本质上突破了传统的二元光谱角（spec- tral angle mapping, SAM)仅能计算两个光谱之间夹角的局限性，具备联合计算多元光谱欧氏空间夹角的能力，为评价多元光谱联合相似性提供了一种定量化的度量手段。
最后，对NSSA方法在高光谱波段选择及端元提取领域的潜在研究价值和应用现状进行了分析和展望。
通过分析表明NSSA方法所具备的特性可更好地实现光谱相似性度量，在 高光谱图像处理领域具有较高的研究价值。
关键词：高光谱图像；光谱相似性度量；二元光谱角；N维立体光谱角方法；多元光谱相似性度量；波段选择；端 元提取D O I: 10. 11990/jheu. 201612063网络出版地址：http://www. cnki. net/kcms/detail/23. 1390. u.20170428. 1622. 064. html中图分类号:TN911. 73文献标志码:A文章编号= 1006-7043(2017)08-1179-11Research progress on spectral similarity metricsZHAO Chunhui,TIAN Minghua,LI Jiawei(College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China) Abstract ：Spectral similarity metrics are important in the field of hyperspectral data analysis.To further analyze their application in hyperspectral image processing,the current binary spectral similarity metrics method based on distance or projection was summarized.The problems in the binary spectral similarity metrics were analyzed and discussed.Then,this study chiefly introduced a multiple spectral similarity metric called N-dimensional solid spectral angle (NSSA).The NSSA method breaks through the limitation of the traditional binary spectral angle mapping in essence,which can not only calculate the angle between two spectra but also the angle constructed by multiple spectra jointly in Euclidean space.The method provides a quantitative measure to evaluate the joint similarity of multivariate spectra.The potential research value and applications of the NSSA method in hyperspectral band selection and endmembers extraction were analyzed and forecasted.The analysis indicates that the NSSA method can better realize the spectral similarity measure and has high research value in the field of hyperspectral imaging process.Keywords：hyperspectral imagery；spectral similarity metrics;binary spectral angle mapping；N dimensional solid spectral angle；multiple spectra similarity metric；band selection；endmember extraction随着成像光谱仪的发展，高光谱遥感成像技术 得到了广泛的关注。
[理学]量子力学
E p c m c
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when m0 = 0,
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∴ the mass of photon is
E h mp 2 2 c c
and the momentum of photon should be
E h h p c c
Example: Ultraviolet light of wavelength 150nm falls on a chromium electrode. Calculate the maximum kinetic energy and the corresponding velocity of the photoelectrons (the work function of chromium is 4.37eV). Solution:
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全息照相的原理英语作文
全息照相的原理英语作文The principle of holographic photography is based on the interference pattern created by the interaction oflight waves. This pattern captures the three-dimensional information of an object, allowing us to reproduce a realistic and detailed image.Holographic photography uses a laser beam to illuminate the object and a photosensitive material to record the interference pattern. The laser light is coherent, meaning that all the light waves have the same frequency and phase, which is essential for creating a clear and sharp hologram.When the laser light reflects off the object, it combines with the reference beam to create an interference pattern on the photosensitive material. This pattern contains information about the object's shape, size, and texture, allowing us to reconstruct a lifelike image when the hologram is illuminated with laser light.Unlike traditional photography, holographic photography captures the complete wavefront of light, preserving both the intensity and phase information. This allows us to reproduce not only the appearance of the object but alsoits depth and spatial relationships, creating a truly realistic representation.One of the key advantages of holographic photography is its ability to capture and display three-dimensional images without the need for special glasses or viewing devices. This makes holograms an ideal tool for scientific research, medical imaging, and artistic expression, opening up new possibilities for visual communication and storytelling.In conclusion, holographic photography offers a unique and powerful way to capture and reproduce three-dimensional images with unparalleled realism and detail. By harnessing the principles of interference and wavefront reconstruction, holograms enable us to experience the world in a new and immersive way, pushing the boundaries of visual representation and storytelling.。
傅里叶光学成像
傅里叶光学成像
傅里叶光学成像是一种通过傅里叶变换分析和处理光学图像的
方法。
傅里叶变换是将一个函数分解成若干个正弦函数和余弦函数的和的方法，而在光学中，这些正弦和余弦函数对应于不同的空间频率。
通过使用傅里叶变换，我们可以将光学图像转换成频谱图，并对其进行分析和处理。
傅里叶光学成像被广泛应用于医学成像、遥感成像以及工业检测等领域。
在医学成像中，磁共振成像（MRI）和计算机断层扫描（CT）都使用了傅里叶光学成像的方法。
在遥感成像中，卫星遥感图像的处理也使用了傅里叶光学成像的技术。
在工业检测中，傅里叶光学成像可以用于检测缺陷和表面质量。
傅里叶光学成像的优点在于，它可以提取出光学图像中的空间频率信息，从而更好地了解图像的细节信息。
此外，傅里叶光学成像也可以去除图像中的噪声和模糊，从而提高图像的质量和清晰度。
总之，傅里叶光学成像是一种非常有用的光学成像方法，它在医学、遥感、工业检测等领域都有广泛的应用。
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a r X i v :q u a n t -p h /0112125v 1 20 D e c 2001Photoconductance Quantization in a Single-Photon DetectorHideo Kosaka 1∗,Deepak S.Rao 1,Hans D.Robinson 1,Prabhakar Bandaru 1,Toshitsugu Sakamoto 2,Eli Yablonovitch 11Electrical Engineering Department,University of California Los Angeles,Los Angeles,CA,90095-15942Fundamental Research Laboratories,NEC Corporation,34Miyukigaoka,Tsukuba,Ibaraki 305-8501,Japan∗On leave from Fundamental Research Laboratories,NEC Corporation.We have made a single-photon detector that relies on photoconductive gain in a narrow electron channel in an AlGaAs/GaAs 2-dimensional electron gas.Given that the electron channel is 1-dimensional,the photo-induced conductance has plateaus at multiples of the quantum conductance 2e 2/h.Super-imposed on these broad conductance plateaus are many sharp,small,conductance steps associated with single-photon absorption events that produce individual photo-carriers.This type of photoconductive detector could measure a single photon,while safely storing and protecting the spin degree of freedom of its photo-carrier.This function is valuable for a quantum repeater that would allow very long distance teleportation of quantum information.PACS numbers:72.20.-i,72.40.+w,73.23.-b,73.63.-b,78.67.-nThe detection of individual photons has become com-mon in the last few decades with the proliferation of avalanche photodetectors,[1]and negative electron affin-ity [2]photocathode photomultipliers.However,it is be-coming desirable now to transmit something more sophis-ticated than single-photon ly,we want to distribute quantum entanglement information over long distances to enable teleportation [3]and other forms of advanced telecommunication.For this,single-photon sensitivity is not enough.New types of single-photon photodetectors are needed,which preserve the spin in-formation of the photo-carrier.New selection rules have been identified in the III-V semiconductor photodetectors,that permit the transfer [4]of photon polarization information directly to photo-electron spin.Unfortunately,the avalanche multiplica-tion process is relatively violent,of necessity,and it de-stroys any spin information that might have been present on the original photo-electron.New forms of single-photon detection have been developed recently,that are gentle enough to preserve the photo-electron spin state,while providing the gain needed to detect a single pho-ton.For example photoconductive gain can provide for single-photon detection.Shields et al.[5]recently demonstrated single-photon sensitivity in a two-dimensional (2D)electron channel controlled by photoelectric charge trapped on adjacent In x Ga 1−x As precipitates in AlGaAs.In photoconduc-tive gain,electric charges become trapped for long peri-ods,and while trapped,their electric charge can influ-ence the channel conductivity.Over time,vast amounts of electric charge can be transferred in the channel cur-rent,far more than the original trapped charge,creating a huge photoconductive gain.Trapping of an individual photo-carrier produces a step function in current that can persist for long periods.In AlGaAs alloys at low temper-ature this is called persistent photoconductivity,and the current can last for weeks.An analogous electrical trans-port sensitivity enhancement was spectacularly used to detect individual far-infrared photons by Komiyamaet-1.5at time t=0in Fig.2A,to the right of the crosshatcheddark region where the conductivity begins as a constant. If the photo-exposure is prematurely terminated,the con-ductance becomes constant again in Fig.2A,persisting at the new value for weeks.Photoconductivity in an electron channel requiresfixedpositive charge from trapped photo-holes.The hole trap-ping centers can be either neutral donors d0,that becomeionized undergoing the transition d0+h+→d+,or they can be DX−centers[14–18]that become neutralized byhole capture,[19]DX−+h+→d0.In any case,the net trapped positive charge has the same effect on the source/drain electron channel as positive gate increments do.The only difference in Fig.2A is that the horizontal axis at the top measures the net positive charge in terms of optical exposure time from a weakλ=700nm beam, and the horizontal axis at the bottom measures positive increase of gate voltage.The same quantum conductance plateaus are produced in either case.When the photon wavelength is reduced toλ=550 nm,well beyond the Al0.3Ga0.7As bandgap,an additional phenomenon appears,that is plotted in Fig.2A,as the curve labeled“λ=550nm”.That curve still follows the overall shape of the quantized conductance steps,but the curve itself consists of many smaller steps that,in aggregate,produce the quantized conductance shape,in-cluding the0.7(2e2/h)feature.The smaller steps,we at-tribute to absorption of individual photons,and the cor-responding capture of a single photo-hole.Since the traps are at variable distances from the source/drain channel, each photon produces a different step height.This is different from the Millikan oil-drop experiment,but sim-ilar to the observations by Shields et al.,[5]who trapped photo-holes on InGaAs islands.The photon steps forλ=550nm in Figs.2A seem to be taller where the conductance curve is steeper,due to greater sensitivity to electrostatic charge changes when dG/dV g is larger.This point is illustrated in Fig.2B,donor defects opens up the source/drain channel creating a permanent increase in electron current.In converse,atλ=700nm,photons are absorbed in the nominally undoped GaAs buffer layer,which is usually weakly n-type.Thus the photo-hole recombina-tion centers,residual neutral donors d0,are very dilute. They are too far away from the source/drain channel to produce noticeable discrete jumps in current for single-photon events atλ=700nm.Nonetheless,the smooth photoconductance channel quantization steps are still ob-served atλ=700nm,as shown in Fig.2A.The photo-electron plays a lesser role.It usually ends up in the channel,and then becomes swept away in the source and drain electrodes.Since those are ohmic con-tacts,they can continue to inject replacement electrons indefinitely.This is essentially the mechanism[22]of secondary photoconductivity and photoconductive gain that is responsible for the single-photon sensitivity. The conductance curve in Fig.2A ends at the2 conductance units(2e2/h)plateau.Above this conduc-tance level,the gate-induced and photo-induced conduc-tance changes no longer match.The photo-induced con-ductance change tends to saturate above2conductance units(2e2/h),after about70discrete photon conductance steps,but the gate-induced change continues to higher conductance.We attribute the saturation of the photo-induced conductance to saturation of the doping-induced trapping centers.Within the active area of3×10−10cm2 there are3.3×1011carriers/cm2or only about100carri-ers,explaining the saturation in photoconductance.At a channel capacitance of≈0.1femto-Farad,the70charges produce about the same electricfield as the gate voltage change of∆V g=0.2Volt that was required to reach the 2(2e2/h)conductance plateau.In this photoconductive single-photon detector,a photo-hole is trapped,producing a discrete change in source/drain channel conductance.If the photosensi-tive layer were strained,the light/heavy hole degener-acy would be lifted,and the hole spin degree of freedom might be a viable long-lived qubit.Strained hole spin coherence has been maintained[23]for about100nsec in p-Silicon.In n-type material however,trapped holes are subject to electron/hole recombination.It is generally accepted[24]that a trapped photo-electron spin is the preferred qubit compared to a photo-hole spin.Electron traps may require artificial engineering,for example,they could be electron potential wells created by electrostatic gates above a heterointerface.In addition to changing the sign of the trapped carrier, a further change may be needed to increase the quantum efficiency.Photoconductive detectors can inherently be quite efficient,since the photo-carriers are produced by band-to-band absorption in a direct bandgap semicon-ductor.Nonetheless,it might be desirable in practice to incorporate the absorbing region into an optical cavity to make it a cavity-enhanced photodetector.In principle,a photoconductive detector can store and detect an optically injected photo-carrier charge,preserv-ing its quantum mechanical spin information.This would safely prevent the charge measurement from disturbing the spin.We have demonstrated single photo-carrier charge sensitivity,but we have used naturally occurring defect centers that are subject to carrier recombination. 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