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Experimental studies of single-event e ects induced by heavy ions qJ.Liu a,*,M.D.Hou a ,B.Q.Li a ,C.L.Liu a ,Z.G.Wang a ,S.Cheng a ,Y.M.Sun a ,Y.F.Jin a ,Y.L.Lin b ,J.R.Cai b ,S.J.Wang b ,Z.H.Ye b ,G.W.Zhu b ,H.Du b ,Q.Y.Ren b ,W.Wu b ,X.M.Mao b ,Y.Q.Sun b ,R.Guo baInstitute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,People's Republic of ChinabCenter for Space Science and Applied Research,Chinese Academy of Sciences,Beijing 100080,People's Republic of ChinaAbstractThis paper presents the results of ground-based heavy ion test of single-event e ect (SEE)vulnerability on micro-circuits used in space.We observed the dependence of upset cross-sections on the incident angle of ions in Intel 8086CPU.SEU cross-sections of various SRAMs did not depend on the stored pattern,but 031and 130transitions were completely di erent for di erent manufacturer products.Some SEE protection methods were veri®ed in conditions of ground simulation experiments.Ó2000Elsevier Science B.V.All rights reserved.PACS:61.80.Jh;85.40.VbKeywords:Single-event e ect;Heavy ion simulation;Microcircuit1.IntroductionMicrocircuits in space interact with various particles and induce a variety of physical phe-nomena known as single-event e ects (SEEs)[1±3].These e ects,including single-event upset (SEU),single-event latchup (SEL),single-event burnout (SEB),etc.,result from the charge deposited by a single particle crossing a sensitive region in the device and are functions of the amount of chargecollected at the sensitive node.SEU and SEL have been observed in space systems and all e ects have been observed and studied in ground-based simu-lations using accelerators.As microcircuits have been reduced in size and charge storage capacity,and owing to a growing interest in the use of commercial devices in space,they have become vulnerable to SEEs in the space radiation envi-ronment.Accurate estimates of its probability in microelectronics used in space systems are impor-tant for system design.The SJ-5research satellite launched in May 1999had a number of SEE investigation systems,aimed at observation of SEEs in devices and sys-tems on board.Before the satellite was launched,ground-based SEE test of microcircuits had been done which permitted characterization ofdeviceqProject supported by National Science Foundation of China(19775058)and the Chinese Academy of Sciences.*Corresponding author.Tel.:+86-931-885-4867;fax:+86-931-888-1100.E-mail address:hiam@ (J.Liu).0168-583X/00/$-see front matter Ó2000Elsevier Science B.V.All rights reserved.PII:S 0168-583X (99)01103-9susceptibility to various radiation-induced distur-bances and dynamically test the equipment [4].We especially observed the angle e ect of SEU and the dependence of upset on the stored pattern,and veri®ed the SEE protection methods.2.ExperimentalThree kinds of heavy ions delivered by the Heavy Ion Research Facility in Lanzhou (HIRFL)have been used to irradiate the microcircuits.Test ions included 132MeV oxygen,1.6GeV neon and 130MeV argon ions.O and Ne ions were con-ducted to air through a thin Ni window.Then,the devices were tested using a scattered O ion beam at 15°angle which was smaller than the h 1a 4angle of nuclear reaction between 132MeV O and Ni nu-cleus.Fig.1shows a schematic diagram of the experimental set-up of the oxygen ion test.The incident ¯ux exposed to the delidded devices was estimated from the counts of the surface-barrier detector mounted at the symmetrical point of the test device with respect to the beam.In the neon ion test,degraders had been used which lowered the primary beam energy by passing the beam through thin aluminum absorbing foils.The inci-dent Ne ion beam was monitored by an air ion-ization chamber detector and then the devices,delidded or with lid,were bombarded.The Ar ions test was done in a vacuum chamber which con-tained a gold scattering foil of 254l g/cm 2.The scattering angle was chosen to be 30°.Changing the scattering angle of the device could vary the ¯ux.Further adjustment of the ¯ux was made byadjusting the accelerator ion current.The obtained beams on the surface of devices were 34.7MeV 18O,96.0MeV 20Ne and 121.3MeV 40Ar ions.Their LETs and ranges in silicon were 5.3MeV/mg/cm 2and 23.8l m,5.3and 58.7,16.5and 29.6,respectively.Every register or memory of the device was loaded with a known pattern in the test.The computer was interfaced to the RS-232line to re-motely control start/stop commands,collect test data,and perform real time test status summary.We measured both the number of cells in which upset occurred due to ion irradiation and the ¯u-ence of the ions.From these data,the upset cross-section could be derived for each device under test.3.Results and discussion 3.1.Angle e ect of SEUFour kinds of devices,which included Intel 8086CPU,IDT 7164SRAM (with polyimide ®lm),2764EPROM and 28C64E 2PROM,were tested by 18O ion.We used self-testing single computer method and chose 3MHz clock fre-quency to test the 8086CPU chips.The single-event upset was observed only in Intel 8086CPU chips,but no latchup occurred in them.No single-event e ects were detected in other devices because di erent devices have di erent thresholds of upset or latchup.By checking the errors that occurred in Intel 8086CPU we found that four 16-bit general reg-isters and four 16-bit special registers were easy to be upset besides the running program being easily hit to ¯y.The measured SEU cross-section (CS)was determined as the ratio of number of upsets to ¯uence.Two batches of Intel 8086chips have been tested.There was about a factor of two di erence in magnitude of CS between them.Possible techniques for varying the deposited energy are di erent ion types and variation of the ion energy.However,the common practice is to vary the angle of incidence of the ion beam upon the chip during testing to provide an e ective LET given by LET eff LET a cos u ,where LET is determined by the ion type and energy and u istheFig.1.Schematic representation of the test apparatus using oxygen ions which consists of the SEE monitor system and the beam ¯uence detector.974J.Liu et al./Nucl.Instr.and Meth.in Phys.Res.B 164±165(2000)973±978angle of incidence.The angle increases the ion path length through the device,therefore increas-ing the e ective LET,LET eff .In this study,the incident angle u of the beam relative to the device board was changed from 0°to 60°by rotating the two mutually perpendicular symmetry axes of the device,i.e.,the long axis and the short axis.It also included both positive and negative rotations.The curves of upset cross-sec-tion on ion LET of rotation about the long and short axes of 8086are shown in Fig.2.Two fea-tures were observed in this ®gure.Firstly,the ab-normality of CS was observed with increasing LET eff ,i.e.,when the LET eff increased the CS de-creased instead of increasing.Secondly,there was a discrepancy in the magnitude of CS between the two axes.The devices exhibited a strong angle ef-fect in this part.These were also observed by other investigators [5]corresponding to decrease of the cross-section with the tilt angle.The ®rst mea-surements of the dependence of charge collection in diodes were reported by Campell and his co-workers [6].The collected charge in the bulk de-vices decreased with the secant of the angle.When plotted versus e ective LET,the curve actually decreased.Discontinuities were observed by Sex-ton and his coworkers [7]where three ion types were used with various incidence angles to vary the e ective LET.Considering that the concept of ef-fective LET was adopted at a time when it could be assumed that the sensitive volume was a thin large-area rectangular parallelepiped,they devel-oped a correction to the CS to account for geo-metrical e ects to high LET ions.The O ion is light and its LET in Si is low.The measured cross-sec-tion corresponds to the situation in which all ions of that LET cannot deposit enough energy to cause an upset when passing through a corner of the sensitive volume.Therefore,even though the total projected area has increased with increasing angle,the total area responsible for the upset has decreased.The projected area has to be reduced by a factor of z sin u considering the edge e ect.The e ective cross-section is [8,9]CS eff CS Âcos u Àzsin u Ywhere CS eff is the e ective cross-section after cor-rection,CS is the measured upset cross-section,and x and z are the width and depth of the sensi-tive volume,respectively.The corrected cross-sec-tion curves of CS eff versus LET eff using this equation assuming that the ratio of z /x was 0.4are also shown in Fig.2.It has been found that the CS abnormality disappears.This e ect could be ex-plained on the basis of geometry e ects.We wanted to study the di erent SEU response curve that might be obtained for a rotation about the two mutually perpendicular symmetry axes in the 8086device.As Fig.2showed,although at the same LET eff the CS eff values were di erent for di erent axes.We thought that two factors have been identi®ed as potential contributors.(1)The characteristic of the charge collection by the junction was observed to vary with angle of inci-dence when the rotation was about the short symmetry axis but not about the long axis [10].Hence,there were di erent reasons for long and short axis rotation to the change in charge col-lection.Both the position of the peak and the number of events under the peak measured at a given angle of incidence depended upon which symmetry axis of the device was chosen to be the rotation axis.These features of the devices can lead to angular dependence in charge collection or charge collection response.(2)The actual charge collection structures of the SEU-sensitive micro-junctions have shapes which are either more complicated than rectangular parallelepipeds or at least are not square.Typically,they haveoneFig.2.Measured and corrected CS of SEU versus e ective LET curves for Intel 8086CPU device about long and short axes rotation.J.Liu et al./Nucl.Instr.and Meth.in Phys.Res.B 164±165(2000)973±978975dimension which is considerably shorter than the other.In Intel8086CPU,if we considered a charge collection volume with dimensions of 5Â20Â2l m3,the correction factors to be ap-plied were0.1and0.4for long axis and short axis rotation,respectively.If we used this correction factor,the CS eff values were almost the same for the two axes.From this we can conclude that the dimension of the sensitive volume was not square in Intel8086CPU,the ratio of x/y was about1/4 with its long dimension parallel to the long axis.3.2.Dependence of upset on the stored patternWe have chosen six types of high density SRAMs as test samples which came from di erent manufacturers and with di erent capacities.In order to reveal di erences in the response to data bit``0''or``1'',we used Ne ions to test SRAM for various input patterns.Di erent patterns were put in the memories,for example,``FF''means that inputting all1in the memories,``00''all0,``55'' and``AA''half0and half1.Table1lists the upset results of the test.It also includes the statistical results of130and031 transitions.No rules about the CS values of SEU were observed when they stored di erent patterns. The SEU sensitivity for0and1was about the same value.But the probability of031and 130transitions was di erent when the half0and 1were stored in the memories.The transition of 031was larger than that of130in6116,6264 and62256SRAMs produced by HITACHI.In contrast to that,the transition of130was far larger than that of031in7164and71256 SRAMs produced by IDT.In this case,greater than90%transitions of upset were130,0state was the preference state.It appeared that the probabilities of031and130transitions de-pended on the technique of di erent manufactur-Table1The results of SEU in SRAMs for di erent patternsDevice Capacity(bits)Manufacturer a Pattern CS Â10À5cm2 031(%)130(%)5A1660.339.7 61162kÂ8HITACHI B FF250043AA9144.455.65A 2.775.524.5 62648kÂ8HITACHI B FF 1.600 4.2AA23.363.636.4FF110FF1106225632kÂ8HITACHI B00190AA14068.131.9FF1571648kÂ8IDT M0013AA200100FF187125632kÂ8IDT M0020AA197.392.7FF 3.9TC551001128kÂ8TOSHIBA B00 2.9AA 3.155.045.0a B represents commercial product and M represents military product.976J.Liu et al./Nucl.Instr.and Meth.in Phys.Res.B164±165(2000)973±978ers,especially in IDT SRAMs.It was very strange that when memories all stored0in IDT SRAMs, their upset cross-sections were not smaller than that of all1.The single bit upset sensitivity ex-hibited a strong discrepancy between the two transition types[11,12],0is much less sensitive than1.It meant that the states of the gates were not entirely symmetrical with respect to0or1 [13,14].These di erences were explained in terms of the geometrical details of the memory storage element and the nodal capacitance of the element.In the experiments we found that although the ions had the same LETs,their SEU results were di erent,the higher the energy actually deposited in the sensitive volume by the ion,the larger the CS of SEU[15].Other authors[16]also found an energy and species dependence of SEU results for a bipolar memory.Stapor et al.[17]also reported an energy in¯uence on the measured cross-section of test vehicles.All these experimental observa-tions con®rmed that LET was not the only pa-rameter to take into account for determining the sensitivity of a device,especially for modern de-vices with small sensitive volumes and low LET threshold.3.3.Protection method veri®cationThe®ve di erent space SEE research instru-ments on board SJ-5satellite were designed to probe the SEE and implement some safeguarding methods to decrease the e ects.Four types of EDAC(error detection and correction)of the system were veri®ed using Ne and Ar ions in the experiments[4].1.Two CPU Redundancy.A system with two CPU working together has been built in one cir-cuit to prepare for resisting the sudden SEE oc-curring in one of them.When errors induced by ions occurred in one of them,the system out-putted several signals to show the errors and changed the CPU's working way.The availabil-ity of this method in the system while SEE oc-curred was proven.2.Reed±Solomon Coding Correction.The RS coding is the most useful to correct the paroxys-mal error like SEU.Based on hardware and software supporting,this kind of EDAC meth-od has been set up in the computer system. When ions are bombarding it,the system de-tects and corrects the error until it run normally.3.Software Self-correction.Software self-correct-ing is a utility to build the program health to op-pose SEU.The CPU and PROM were bombarded using Ne and Ar ions.The output showed that the software self-correction was running well for program setup and handling well against SEU at®rst.But the system failed because of SEL occurred at last.4.Brainpower Controller against SEL.To avoid the SEL,the device must be in a radiation hard-ness type.In the circuit,some safeguard against SEL must be set up such as restricting current.A new brainpower controller has been installed into the space computer system to restrict the abnormal current as soon as the SEL occurred. The testing controller has been®nished and tested using Ne and Ar ions.The devices had a longer lifetime in radiation environment using this controller system.4.ConclusionSEE susceptibilities of microcircuits to radia-tion environment were tested using three kinds of heavy ions at HIRFL.The Intel8086CPU device exhibited strong angle e ects when the device was tilted along its rotation axis.This abnormality of CS versus LET eff was corrected using a geometri-cal method.The di erent responses of SEU sen-sitivity existed when a di erent axis of device was chosen as the rotation symmetry axis.So it is necessary to have much information about the structure of the device and measure the SEE vul-nerability along the two axes.In various SRAMs, we observed that their SEU cross-section did not depend on the stored pattern,but031and130 transitions were completely di erent for di erent manufacturer products.We also found an energy deposition dependence of SEU results despite the same LET value of ion.Four types of EDAC protection methods of SEE were veri®ed in the experiments,including two CPU redundancy,RS coding correction,software self-correction and brainpower controller methods.J.Liu et al./Nucl.Instr.and Meth.in Phys.Res.B164±165(2000)973±978977References[1]D.Binder,E.C.Smith,A.B.Holman,IEEE Trans.Nucl.Sci.Ns-22(1975)2675.[2]W.A.Kolasinski,J.B.Blake,J.K.Anthony,et al.,IEEETrans.Nucl.Sci.NS-26(1979)5087.[3]J.C.Pickel,IEEE Trans.Nucl.Sci.43(2)(1996)483.[4]Y.L.Lin,Z.H.Ye,G.W.Zhu,et al.,in:Proceedings of the11th Conferece on Space Science and Detection,Hainan, China,1998,p.315.[5]S.Duzellier,D.Falguere,L.Mouliere,et al.,IEEE Trans.Nucl.Sci.42(6)(1995)1797.[6]A.B.Campbell,A.R.Knudson,P.Shapiro,et al.,IEEETrans.Nucl.Sci.NS-30(1983)4486.[7]F.W.Sexton,J.S.Fu,R.A.Kohler,et al.,IEEE Trans.Nucl.Sci.36(6)(1989)2311.[8]E.L.Petersen,IEEE Trans.Nucl.Sci.39(6)(1992)1577.[9]E.L.Petersen,J.C.Pickel,E.C.Smith,et al.,IEEE Trans.Nucl.Sci.40(6)(1993)1888.[10]P.J.Mcnulty,W.J.Beauvais,R.A.Et Al Reed,IEEETrans.Nucl.Sci.39(6)(1992)1622.[11]P.Calvel,mothe,C.Barillot,et al.,IEEE Trans.Nucl.Sci.41(6)(1994)2267.[12]J.Liu,F.Ma,M.D.Hou,et al.,Nucl.Instr.and Meth.B135(1998)239.[13]G.J.Brucker,W.Chater,W.A.Kolasinski,IEEE Trans.Nucl.Sci.NS27(1980)1490.[14]F.L.Hsueh,L.S.Napoli,IEEE Trans.Nucl.Sci.NS32(6)(1985)4155.[15]J.Liu,Thesis,1999,Institute of Modern Physics,ChineseAcademy of Sciences.[16]T.L.Criswell,D.L.Oberg,J.L.Wert,et al.,IEEE Trans.Nucl.Sci.NS-34(6)(1987)1316.[17]W.J.Stapor,P.T.McDonal,A.R.Knudson,et al.,IEEETrans.Nucl.Sci.NS-35(6)(1988)1585.978J.Liu et al./Nucl.Instr.and Meth.in Phys.Res.B164±165(2000)973±978。
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注：英语原文来自SCIENTIFIC AMERICAN《科学美国人》第一篇：回归自然：聆听昆虫爱乐乐团交响曲 (1)第二篇：阑尾并非可有可无 (3)第三篇：今朝寻醉，明日“买单” (5)第四篇：大脑中掌管求“变”的部位 (6)第五篇：世界上最疯狂的地球工程方案 (8)第六篇：笔迹测谎 (10)第七篇：挑战交织在一起：气候变暖和能源使用 (11)第八篇：网瘾是病吗？ (13)第九篇：释放心灵，忘记不快 (15)第十篇：破解香槟之谜：关键是泡沫 (17)第一篇：回归自然：聆听昆虫爱乐乐团交响曲Allison Beall of the Marshlands Conservancy in Rye, N.Y., led a twilight walk on September 5th to tune in to the insect sounds of the evening. Become more aware of the nocturnal symphony and, in the New York metropolitan area, help scientists count the insects during the "Cricket Crawl" on September 11th.Allison Beall在纽约拉伊（Rye）的湿地保护区（Marshlands Conservancy）工作，她在9月5日的傍晚带领我们散步，去聆听夜间昆虫的声音。
在庆祝9月11日的“蟋蟀爬行日”时候，请进一步意识到我们周围的夜间交响乐，同时在纽约市区帮助科学家们统计这些昆虫。
回归自然：聆听昆虫爱乐乐团交响曲Tuning In to the Insect Philharmonic“Can you hear the end of the daytime insect? That’s the cicada. But I’m hearing crickets in the background, too. And just listen for a second, listen to how many different sounds you can hear.” That’s Allison Beall of the Marshlands Conservancy, a wildlife sanctuary in Rye, New York. She led a twilight walk through the preserve on September 5th.“There’s a wonderful event that’s about to take place, on September 11th. There’s going to be a 'Cricket Crawl,' where people are going to go out and listen for the sounds of seven crickets and katydids, angle-winged katydids, and coneheads and various other night insects that are singing. And you can go to a Web site, and you can go out into your own backyard and listen for the sounds and actually be part of this scientific count. So all of the sounds are on the Internet, you can listen, you can see the insect close-up, and you can hear the sounds, and then you can send in the data from your own backyard.”The Web site is /cricket or just google “Cricket Crawl.” The official count is taking place in the New York City metropolitan area, but anyone canget a new appreciation for the tiny wildlife producing nature’s nocturne.“Okay, so we are just about at the end of this walk, and I want to tell you something. It has not anything to do with this walk, this is called a crepuscular walk. It was just a trick, it was a trick to get you to go outside in your own habitat and to listen for the same things that have been in your backyard or in your neighborhood all along and you just haven’t paid any attention to them. So here’s what I recommend. You go out and you get a flashlight, and at eight o’clock go out and follow the sounds that you’ve heard here tonight. Do you realize how many different species of crickets and katydids and grasshoppers there are? And your job is to find them.”聆听昆虫爱乐乐团交响曲“你能听到白天昆虫停止鸣叫吗？那是蝉。
Mars Rover Spirit Is Dead Silent--but May Not Be DeadAugust 2, 2010 As many of us broil in August heat, the Mars rover Spirit is hunkered down to survive a far more brutal season—a Martian winter. Spirit’s been on Mars since January 2004 and already survived previous winters, which run from May through November. With sunlight reaching Spirit at a weak angle, the rover hibernates and uses the scant solar power to recharge batteries and heat itself to –40 degrees [Fahrenheit].At least, that’s what’s happened in previous winters. This winter, the game little unit just doesn’t have enough juice to keep its heaters on, so temperatures inside the rover will plunge to a frigid –67 degrees Fahrenheit.When NASA scientists began signaling Spirit on July 26, they hoped to receive a communications beep back—but so far there’s only silence.The researchers say that in about two months sunlight will start to increase again through March 2011. If we haven’t heard from Spirit by that point, then the likelihood is that we never will. The rover was designed to work on Mars for three months, but was mobile for more than five years. Now mission scientists wait through the Martian winter to see if this ET will phone home.—Cynthia GraberPhysics Students Reveal Bias for Male LecturersAugust 3, 2010 Why aren’t there more women physicists, and in senior positions? One factor may be unconscious biases that could keep women physicists from advancing—and may even prevent women from going into physics in the first place.Amy Bug, a physicist at Swarthmore College, examined the bias question.* Her research team trained four actors—two men, two women—to give a 10-minute physics lecture. Real physics classes watched the lecturers. Then the 126 students were surveyed.When it came to questions of physics ability—whether the lecturer had a good grasp of the material, and knew how to use the equipment—male lecturers got higher ratings by both male and female students.But when asked how well the lecturer relates to the students, each gender preferred their own. And while female students gave a slight preference to female lecturers, male students overwhelmingly rated the male lecturers as being superior. The research appears in the journal Physics World. [http://bit.ly/b3ctOj]Bug says the results may be evidence of inherent biases that could hold women back—along with economic inequalities, such as lower wages and smaller start-up grants. Which reduce career acceleration and thus the amount of force available to crack the glass ceiling.—Cynthia Graber*Correction (8/3/10): This sentence has been edited to correct an error conveyed by this podcast. Swarthmore College was originally identified as Swarthmore University.Hot Peppers' Capsaicin Helps Hypertensive RatsAugust 4, 2010 Here’s a possible blood pressure remedy. But it’s only for those who can stand the heat. It’s capsaicin, the “active ingredient” in peppers like habaneros that should probably be sold by prescription only. While lips burn and eyes water, blood vessels actually relax, thanks to increased production of the signaling molecule nitric oxide. In rodents, anyway.For seven months, researchers in China fed a steady diet of capsaicin to rats bred to be hypertensive. Long-term consumption of the chemical substantially lowered the rats’ blood pressure. The results appear in the August issue of the journal Cell Metabolism. [Dachun Yang et al., http://bit.ly/aLcuZZ]Previous research found mixed results with capsaicin, but those studies only looked at short-term effects. Human trials are needed, but there’s already a clue. Some 20 percent of people in northeastern China have high blood pressure. But the southwest—where hot peppers are a dietary staple—has a much lower incidence, half in some places.Human studies could also confirm whether the habanero, as legend has it, can cause hearing loss. Allegedly so that diners don’t have to listen to their own screams.—Adam Hinterthuer[The above text is an exact transcript of this podcast.]Audio Finds Frog Counters May Be OverestimatingAugust 5, 2010 Declining frog populations are considered an indicator of environmental damage. But new research finds that frogs might be doing even worse than we thought. Because the volunteers who count frogs by their sounds may be overestimating.The North American Amphibian Monitoring Program is the country’s largest frog-counting system. Volunteers listen for frogs, identify the species, and give population estimates. They’ve been doing this for over a decade.Ted Simons from North Carolina State University and colleagues put recordings of frogs, like this wood frog, [Wood Frog sound] in the field to test the volunteers. They call it Ribbit Radio.Many volunteers ended up with false positives—they named frog species whose calls weren’t being played. So there may be fewer frogs, or less variety, than the surveys suggest. The results appear in the journal Ecology. [Brett McClintock et al., http://bit.ly/9iPhUs]Simons is working with the U.S. Geological Survey—in charge of the amphibian monitoring—to account for these false positives, and to better train the volunteers—so they don’t write down “chorus frog” [Chorus Frog sound] when all there really was were pickerel frogs. [Pickerel Frog sound] Apparently, it’s not easy being green, for humans either.—Cynthia Graber[The above text is an exact transcript of this podcast.]Transgenic Canola Plants Break Free of FarmAugust 6, 2010 One of the concerns about working with genetically modified crops has been that vegetation growing in agricultural fields might escape out into the world. Now, for the first time in the U.S., researchers report a large population of GM crops beyond the farm.Transgenic canola plants in North Dakota had received genes making them resistant to herbicides, such as the weed killer Roundup. Researchers collected and tested 406 canola plants along thousands of miles of state roads. They found 347 carrying at least one resistance gene. There were also indications that the inserted genes were being passed on to new generations, producing some plants in the wild with multiple transgenes. The findings were presented on August 6th at the annual meeting of the Ecological Society of America in Pittsburgh. [Meredith Schafer et al., University of Arkansas]The transgenic canola plants are not about to take over the world. But researchers are obviously curious about how these particular plants managed to make it in places like the edges of parking lots rather than pampered fields. Any answers they find will likely affect future biotechnology regulation.—Molly Webster[The above text is an exact transcript of this podcast]Blue Whales Synchronize Song PitchAugust 9, 2010 Blue whales off the California coast make calls that, sped up 10 times, sound like (sound of two-part call). The original is a wall-rattling frequency too low for us to hear. Scientists analyzed around 2,500 of those calls, and found that the second part (sound) is nearly identical in pitch every time from each whale: 16 hertz, or four octaves below middle C. And the slight variations in frequency that do exist are only a tenth of the difference between a C and a C sharp. Those findings appear online in the Journal of the Acoustical Society of America. [Michael Hoffman, Newell Garfield and Roger Bland, http://bit.ly/9oCoP0]The researchers don't know how many different individual whales they caught singing, or why even they sing at all. But past studies suggest only blue whale males make calls like this. So the investigators speculate that males might synchronize to a single common pitch as a sort of mating beacon.Thanks to the Doppler effect, females swimming towards a male would hear a slightly higher pitch; swimming away, a lower-pitched moan. Serenade out of tune—you might be swimming solo tonight.--Christopher Intagliata[The above text is an exact transcript of this podcast.]Case Study: Tongue Stud Play Causes Front Teeth GapAugust 10, 2010 That’s what it might sound like if I had a tongue stud, hitting my teeth. Maybe you’ve seen people with studs in their tongue clicking it up against their front teeth, a move known as “playing.” But it turns out that the habit may destroy some smiles.University of Buffalo researchers noticed that local high school students who had a barbell-type tongue stud commonly pushed the piercings against their front teeth. Then they examined a 26-year-old patient at the school’s dental clinic. She’d had been complaining about a large gap that had developed between her front two teeth. Seven years previously, she got a tongue stud. And every day, for seven years, she pushed that stud up against her teeth.The researchers say tongues are strong, and it makes sense that the force of “playing” will move teeth, even forcing them apart. The case was written up in the Journal of Clinical Orthodontics. [Sawsan Tabbaa, Ivanka Guigova and C. Brian Preston, ]Tongue piercings have also been associated with infections, chipped or broken teeth, and gum trauma. And the patient? She got braces to push her teeth back together. Which probably didn’t look quite as cool as she thought the tongue stud was.—Cynthia Graber[The above text is an exact transcript of this podcast.]Almost a Million Years Added for Earliest HumanAncestor Stone Tool Use and Meat-EatingAugust 11, 2010 There’s nothing like a good steak. And our Australopithecus afarensis ancestors apparently felt the same way. Because new discoveries from Ethiopia show that what was likely the species of the famous fossil Lucy used stone tools to butcher meat from big mammals—about 3.4 million years ago. That’s a million years earlier than our best previous evidence for human ancestor stone tool use and meat eating. The finding appears on the cover of the journal Nature. [Shannon P. McPherron et al., http://bit.ly/dzCs4d]The research team found two fossil bones with cut and scrape marks, signs of meat carving. One bone was a piece of rib from a cow-sized mammal; the other, a leg bone fragment from a mammal the size of a goat. The bones also had percussion marks, sustained while Lucy’s friends smashed the bones to get at the marrow.It looks like the ancient tool users collected stones that happened to have shapes conducive to butchering, the way kids select particular stones with good potential to skip on water. But future expeditions will look for evidence for any attempts at shaping stones into kitchen utensils. Because after 3.4 million years, Lucy and her fellow afarensis keep surprising us.—Steve Mirsky[The above text is an exact transcript of this podcast.]Sound Sleepers' Brain Waves Block SoundsAugust 12, 2010 Ahhh, sleep. There’s nothing better than a nice, long, uninterrupted [LOUD NOISE]. Awwgh. I can’t sleep when there’s [NOISE]. But d’ya ever notice: noise [NOISE] doesn’t wake everyone. Now scientists have a better idea why. Because sound sleepers show a certain brain rhythm when they doze, findings published in the journal Current Biology. [Thien Thanh Dang-Vu et al., http://bit.ly/cORe7D]To study the brain waves of a good night’s sleep, scientists invited volunteers to snooze in the lab. While the subjects caught some Zs, the researchers monitored their brain activity. They then subjected the sleepers to [NOISE] or [NOISE]. And they found that those who were able to slumber straight through all the [NOISE] showed more short bursts of faster brain waves. This activity, the scientists say, is the brain’s way of blocking out the [NOISE] and the [NOISE] while you’re trying to rest.The scientists don’t yet know of any way to boost those sleep-saving brain waves. So until then, shut the door [DOOR SHUTTING], make sure the late show’s on a timer [TV SOUND], and try to have sweet dreams.—Karen Hopkin[The above text is an exact transcript of this podcast.]Pour Champagne on the Side for Better FlavorAugust 13, 2010 You don't have to be a champagne buff to want the best flavor from your bubbly. So the secret to a perfect glass? It's all in the pour, according to a study in the Journal of Agricultural and Food Chemistry. [Gerard Liger-Belair et al., http://bit.ly/cmmEOH]A key player in champagne's taste is its dissolved carbon dioxide. As that CO2 bubbles out, it releases aroma, and provides that tingly bite. As soon as you uncork a bottle, CO2 starts diffusing from the champagne into the air. But pouring it speeds up that process, by increasing surface area and turbulence.Chemists—French ones, of course—poured champagne into fluted glasses two ways. The traditional way, straight down, splashing off the bottom—and the beer way, onto the side of a tilted glass. Then they measured the CO2 lost during the pour.At 40 degrees Fahrenheit, champagne poured traditionally quickly lost a quarter of its carbon dioxide. But pouring down the side caused only half the gas loss. Closer to room temperature, the drink became flat fast, whatever way you pour. So if you want your champagne très bon, keep it cold. And pour that bubbly like it’s Bud.—Christopher Intagliata[The above text is an exact transcript of this podcast.]Invasive Species Lets Other Species Disrupt EnvironmentAugust 16, 2010 At Point Reyes National Seashore in Marin County, California, a plant called Tidestrom’s lupine is holding on for dear life. Its survival has been threatened by the appearance of another plant, an invasive species called European beachgrass. So, does the beachgrass simply outcompete the lupines for land and light? Not at all, according to researchers at Washington University in St. Louis.Tiny deer mice have a taste for the seeds of the lupines. These critters would ordinarily think twice about approaching the plants. Because exposed out on the sand, they’re easy pickings for birds interested in a rodent repast. But the beachgrass provides excellent cover. The mice use the grass to get close enough to pilfer seeds before any hungry birds pilfer the mice. The research appears in the August issue of the journal Ecology. [Emily Dangremond, Eleanor Pardini and Tiffany Knight, http://bit.ly/9yaeIK]The information may be useful for a proposed dune restoration project. And the unexpected consequences of the invading species bring to mind this well-known comment by ecologist Aldo Leopold: “To keep every cog and wheel is the first precaution of intelligent tinkering.”—Steve Mirsky[The above text is an exact transcript of this podcast.]Public Underestimates Savings of Energy EfficiencyAugust 17, 2010 Most of us know we should rein in our energy use. But to be successful, it’d help if we knew the best way to do it. So scientists asked more than 500 people, “What’s the most effective thing you can do to conserve energy?” The results were illuminating.More than half the participants focused on conservation by curtailment: switching off the lights, changing thermostat settings and driving less. Only 12 percent went for efficiency: using compact fluorescent bulbs, insulating the house or driving a hybrid car. But scientists say that it’s actually these moves that yield the bigger energy savings. The results appear in the Proceedings of the National Academy of Sciences. [Shahzeen Attari et al., http://bit.ly/bEtA6W]The study authors think that a big factor is that curtailment is easier to imagine doing—while efforts to improve efficiency would involve, for example, doing research about new appliances or cars, and spending money up front to buy them.But if people knew more about the actual energy requirements of their activities versus the savings available through efficiency, they might be spurred to act. To quote physicist and energy expert Arthur Rosenfeld: “Energy efficiency is like a Saudi Arabia under our cities.”—Karen Hopkin[The above text is an exact transcript of this podcast.]Atlas Identifies Regions of Worm InfectionsAugust 18, 2010 Shakespeare noted that a worm may eat a king, after that king is dead. Sadly, parasitic worms infect people who are still alive, especially kids. Public health advocates estimate that a third of the people on earth are infected with parasitic worms, called helminthes, particularly in poorer areas with inadequate sanitation.Helminths harm health, but also interfere with nutrition and even academic advancement. So the London School of Hygiene and Tropical Medicine, with the Partnership for Child Development at Imperial College London, launched what’s called This Wormy World. It’s an atlas of the distribution and prevalence of helminth diseases, including roundworm, hookworm and whipworm. []It’s often easy to control the parasites with cheap treatments. But resources get wasted because deworming programs are targeted at the wrong communities. The atlas should help the eradication fight by letting health officials know just where the problem areas are.The scientists have been collecting data for the past decade. Their first map focuses on Africa, where worm infestations are worst. Maps for the rest of the worldwill be out by the end of 2010—providing a complete picture of this wormy world of ours. And a new tool to tackle it.—Cynthia Graber[The above text is an exact transcript of this podcast.]Trusting Souls Excel At Spotting LiarsAugust 19, 2010 When you think of someone who’s trusting, you may assume that they’re gullible. But that’s not necessarily true—a fact that your Pollyanna pal might be in a good position to point out. Because people who have faith in their fellow human beings are actually good at spotting lies. The finding is described in the journal Social Psychological & Personality Science. [Nancy Carter and J. Mark Weber, http://bit.ly/bOEFLN]Researchers videotaped a cadre of second-year MBA students as they pretended to interview for a job. Half the interviewees were entirely truthful, and half told at least three whoppers, lies they thought would make them more attractive candidates for the fake job.The scientists then showed these videos to a second set of subjects and asked them to rate the honesty of the interviewees and say which ones they’d hire. The results: subjects who said they think that most people are basically honest, good-natured, and kind were better at spotting the liars than the self-described cynics. Subjects who were more suspicious were, ironically, more likely to hire the liars and less likely to detect their fabrications.So trust may lend itself to better interpersonal intuition. And if you don’t believe that, well, maybe you’re just not being honest with yourself.—Karen Hopkin[The above text is an exact transcript of this podcast]Low-Level Moral Transgressions Make Us LaughAugust 20, 2010 Everyone from Freud to Tina Fey has tried to understand why some things are funny. Now, new research concludes that one key to comedy is for a situation to violate a moral standard, but in a gentle way.Researchers presented volunteers with a number of different scenarios. For example, the Jimmy Dean sausage company needs a spokesman for its new line of pork products, so they hire Rabbi Shlomo Rosenfield. Or, so they hire a farmer. Participants were more likely to find the rabbi scenario wrong, but they were also more likely to think it was funny.The researchers found that participants would laugh at situations with moral violations if, for example, they felt that situation was hypothetical, harmless or involved people unconnected to the listener. The study appears in the journal Psychological Science. [A. Peter McGraw and Caleb Warren, http://bit.ly/c48IZJ]The finding deviates from previously published psychology studies which equate moral violation solely with disgust. It also proves that Mel Brooks was onto something when he said, “Tragedy is when I cut my finger. Comedy is when you fall down an open sewer and die.”—Molly Webster[The above text is an exact transcript of this podcast]Solar Panels Dust Themselves OffAugust 23, 2010 Imagine giant fields filled with photovoltaic solar panels, soaking up rays. The best spots to put such panels are obviously sunny, with little rain. But such places often come with lots of dust. And the panels have to stay dust-free: just a seventh of an ounce of dust per square yard of panel can decrease solar power conversion by 40 percent. And panels in Arizona might get covered with four times that much dust each month.Cleaning the panels conventionally uses precious water. So researchers are turning to dust-cleaning technology developed for one of the driest, dustiest locations possible: Mars. The work was reported at the national meeting of the American Chemical Society. [Malay Mazumder et al]An electrically-sensitive transparent material is deposited on glass or a plastic sheet that covers the panel. Sensors monitor the dust levels. Once the dust reaches a specified level, the system reacts and produces a charge, with electricity generated by the panel.The charge creates a wave over the material’s surface that physically lifts the dust and tosses it over the edges. The system gets about 90 percent of the dust in a couple of minutes. So the panels can go back to soaking up rays.—Cynthia Graber[The above text is an exact transcript of this podcast]。
美《科学》杂志揭晓今年十大科学进展发现“上帝粒子”居首美国《科学》杂志网站20日公布了该刊评选的2012年十大科学进展，其中发现被称为“上帝粒子”的希格斯玻色子被列为本年度最大科学突破。
希格斯玻色子是英国教授彼得·希格斯在上世纪60年代的理论研究中预言存在的粒子，是物质的质量之源，其他粒子在希格斯玻色子构成的“海洋”中“游弋”，受其作用而产生惯性，最终才有了质量。
在物理学“标准模型”所预言的基本粒子中，希格斯玻色子是最后一种被证明存在的基本粒子，由于它极为重要又难以寻觅，曾有人开玩笑说它是“上帝诅咒的粒子”，后来常被称作“上帝粒子”。
欧洲核子研究中心今年7月4日宣布，该中心的两个强子对撞实验项目——atlas和cms均发现一种新的粒子，具有和科学家们多年以来一直寻找的希格斯玻色子相一致的特性。
数据的确定性为5西格玛，即理论物理界可以确认“发现”的水平。
《科学》杂志认为，这项发现将“标准模型”拼图中的最后一块填充到位，虽然尚不清楚该发现未来将把粒子物理领域引向何处，但其对物理学界的重大影响不可否认。
《科学》杂志总编辑布鲁斯·艾伯茨在社论中表示，希格斯玻色子的发现“既是人类智慧的胜利，也是全球数千名物理学家和工程师数十年辛勤工作的顶峰”。
其他九项进展包括：丹尼索瓦人基因组：德国马克斯·普朗克进化人类学研究所科学家开发出一种将特定分子与单股dna相结合的新技术。
通过这种技术，他们利用一个距今7.4万年至8.2万年的指骨碎片获得了丹尼索瓦人的基因组高覆盖率测序数据，重建其基因组全序列。
从如此古老的样本中制作出高品质全基因组，意味着科学界在古代dna测序领域取得巨大进步。
用干细胞制造卵子：日本京都大学研究小组今年10月报告说，他们首次利用诱导多功能干细胞成功培育出实验鼠的卵子，并使其受精从而诞出健康小鼠。
实验结果未能达到科学家们的终极目标——完全在实验室中得到卵细胞，但它为研究基因及其他影响生育和卵细胞发育的因素提供了强有力工具。
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e e n d o n e s h o w in gt h e c a p a b il it y o fa v is io n s y s t e m f o rd e t e c t in ga n d me a s u r in gd e f e c t s o n n o n-mo v in g3D r e‡e c t iv ema n u f a c t u r e dp r o d u c t s.F o rt h is n e win d u s t r ia la p p l ic a t io n,d e f e c t s w ea r et r y in gt o d e t e c ta r ed u s t s in c l u d e d u n d e rt h e me t a l l icl a y e ro fp r o d u c t s.T h ed e f e c td e t e c t io n is s t il lb a s e d o n t h eu s e o fa s pe c i…cl ig h t in gs y s t e m c o mpo s e d o fl ig h ts t r ipe s.B y e x a min in gt h e r e‡e c t io n o fl ig h tf r o m o bj e c t,w e a r ea b l et od e t e c td e f e c t s b e t w e e nt w oc o n s e c u t iv ew h it es t r ipe s.T h eo p t ima ld e t e c t io n h a s b e e no b t a in e db ya d j u s t in gt h ec h a r a c t e r is t ic so ft h el ig h t in gs y s t e m w h il et a k in gin t oa c c o u n tt h e3D g e o me t r yo ft h ed e f e c t st ob ed e t ec t e d.T h ema c h in ev is io ns y s t e m pe r f o r ms t h ec o n t r o lo fo n ec y l ind r ic a lp r o d u c tw it h in o n ese c o n d.Ke y w o r d s:Q u a l it y Co n t r o lb ya r t i…c ia lv is io n,L ig h t in gs y s t e m,R e‡e c t iv eSu r f a c e s,R e a lT imec o n t r o l, M o v in gP r o d u c t s.1IN T R O D U C T IO NN o w a d a y s,ma n u f a c t u r e r s a t t a c hg r e a timpo r t a n c et ot h eq u a l it yo ft h e irma n u f a c t u r e dp r o d u c t s.Q u a l it y c o n t r o lo c c u r sd u r in gt h ep r o d u c t io nt h r o u g hd i¤e r e n tw a y s s u c ha s f u n c t io n a lc o n t r o l,p r o c e s sc o n t r o l,a sw e l l a s a s pe c to rd ime n s io n a lc o n t r o l.In o r d e rt or e a l iz et h e s e c o n t r o l s,a r t i…c ia lv is io n is t o d a y av e r y c o mmo n, u s e f u l lt o o l.T h e q u a l it y c o n t r o la p p l ic a t io n w e a r e p r e s e n t in gin t h is p a pe rc o n c e r n s t h e d e f e c td e t e c t io n o n me t a l l ic o bj e c t s.Sin c et h el a s tf e wy e a r s,q u a l it y c o n t r o la p p l ic a t io n s h a v e b e e n pe r f o r me d o n e it h e rp l a n e r e‡e c t iv e s u r f a c e s[1]o rr o u g h3D me t a l l ics u r f a c e s[2][3].Int h er e c e n tpa s t,r e s e a r c h w o r k[4][5]h a s b e e n d o n es h o w in g t h e c a p a b il it y o fav is io n s y s t e m f o rd e t e c t in ga n d me a s u r in gd e f e c t s o n n o n-mo v in gr e‡e c t iv ema n u f a c t u r e d p r o d u c t s.T h ev is io ns y s t e m s h o w nin[6]is a b l et oc o n t r o ld u s t s in c l u d e du n d e rt h eme t a l l icl a y e ro fp r o d u c t s b y u s in gao r ig in a ll ig h t in gs y s t e m.T h ed e f e c td e t e c t io n me t h o d c o n s is t s in e x a min in g[7][8][9]t h er e‡e c t io n o ft h el ig h t in gs y s t e m o n o bj e c ts u r f a c e.O u rc o n c e r n,f o rt h is p r e s e n t e d in d u s t r ia la p p l ic a t io n,is s t il lt h e c o n t r o lo fh ig h l y r e‡e c t iv e o bj e c t s.T h e u s e d d e f e c td e t e c t io n me t h o d is a l s ob a s e do n t h e u s eo ft h is s pe c i…cl ig h t in gs y s t e m.T h eo r ig in a l it y o ft h is ¤F u r t h e ra u t h o rin f o r ma t io n-Sc h o l a r s h ip o ft h e B u r g u n d y R e g io n a lCo u n c il.n e wr e s e a r c h w o r k c o n c e r n s t h e o n -l in e c o n t r o lo f3D h ig h l y r e ‡e c t iv e ma n u f a c t u r e d p r o d u c t s f o rw h ic h t h e ma in c o n s t r a in tt od e a lw it h is t h eh ig h p r o d u c t io n r a t et h a tis a b o u to n ep r o d u c tw it h in as e c o n d.F ig u r e1:T h ep r o d u c tt oc o n t r o lv ie wu n d e ra m b ia n tl ig h t in gF ir s t ,w e a r e b r ie ‡y p r e s e n t in gt h e u s e d l ig h t in gs y s t e m a n d t h e n it s mo d e l iz a t io n in o r d e rt o d e …n e it s c h a r a c t e r is t ic s a l l o w in gin t h a tw a yt h eo p t ima ld e t e c t io n o ft h ed e f e c t s .F a s tima g ep r o c e s s in ga r et h e n p r e -s e n t e da l l o w in gt h ec o mp l e t e ,f a s td e f e c td e t e c t io n .T h ed e c is io n a b o u te it h e ra c c e p t in go rr e j e c t in gp r o d u c t s isma d ea c c o r d in gc r it e r ias u c ha sn u mb e ro fd e t e c t e dd e f e c t sa n dn u m b e ro fp ix e l sf o re a c hd e f e c t .T h isa r t ic l e is e n d e db yt h ep r e s e n t a t io no fc o mpl e t ein d u s t r ia ls y s t e m p r o t o t y pe .2D E SC R IP T IO N O F T H E L IG H T IN G SY ST E M F O RD E T E C T IN G D E F E C T S O N R E F L E C T IV E SU R F A C E SD e s p it e t h e u s e d l ig h t in gs y s t e m h a s b e e n a l r e a d y p r e s e n t e d in [4][6],w e a r e b r ie ‡y d e s c r ib in gitin t h is s e c t io n .It s p r in c ip l e c o n s is t s in o b s e r v in gt h e r e ‡e c t io n o fa s pe c i…c l ig h t in g o n t h e o bj e c ts u r f a c e t h a tis c o mp a r a b l et oamir r o r .T h el ig h t in gis c o mpo s e do fl ig h tt r a n s it io n s a s itis s h o w nin…g u r e4a .Sin c ed e f e c t s a r el o c a t e du n d e rt h eme t a l l icl a y e rt h e yl o c a l l yc h a n g et h es u r f a c eo r ie n t a t io no fo bj e c t s .D e f e c t s r e ‡e c tl ig h t r a y s d i¤e r e n t l y a s s u r r o u n d in g‡a w l e s s s u r f a c e s (…g u r e 2b )a n d t h e y a p pe a rb y r e ‡e c t io n e it h e rw h it e o n a b l a c kb a c k g r o u n do rb l a c ko n aw h it eb a c k g r o u n da s w es e ein …g u r e3.Specular2(a)(b)F ig u r e 2:a )s h o w s t h e p r in c ip l e o ft h e u s e d l ig h t in gs y s t e m,a n d b )g iv e s t h e l u min o u s r a y s in t h e c a s e o f d e f e c tdF ig u r e3:D e f e c t s c a na p pe a rw h it eo n ab l a c kb a c k g r o u n do rb l a c ko n aw h it eo n eT h e q u a l it y o ft h e d e f e c td e t e c t io n d e pe n d s ma in l y u po n t h e d is t a n c e d r e f e r e n c e d a b o v e b e t w e e n t h e d e f e c t s a n d t h ebe g in n in go ft h et r a n s it io n o fl ig h t .T h ed is t a n c eis f u n c t io n o ft h eo bj e c ts h a pe ,t h el ig h t in g s y s t e m,a n d t h e o r ie n t a t io n s o fb o t h t h e c a me r a a n d t h e l ig h t in g s y s t e m w it h r e s pe c tt o t h e o bj e c tbe in g c o n t r o l l e d .T h ef o l l o w in gs e c t io np r o v id e s ama t h e ma t ic a ld e s c r ip t io no ft h eu s e dl ig h t in gs y s t e m a l l o w in gt h e d e t e r min a t io n o ft h eo p t ima ls e to ft h ev is io n s y s t e m p a r a me t e r s .2.1L ig h t in gs y s t e m m o d e l i n gW e p r e s e n tin …g u r e 4a 2D o pt ic a lmo d e lo ft h e v is io n s y s t e m in c l u d in g t h e CCD ma t r ix ,t h e p in h o l e mo d e lo ft h ec a me r a(fis it s f o c a ll e n g t h ),t h el ig h t in gs y s t e m a n dt h eo bj e c tt ob ec o n t r o l l e d .CCD MATRIXLIGHTING S(0,z s →j →k→i F ig u r e4:g e o me t r ic a lmo d e lo ft h ev is io n s y s t e m in c l u d in gt h ea x is o fb o t h c a me r aa n dt h el ig h t in gs y s t e m.F r o m t h is mo d e lw e c a n f o r mu l a t e t h e f o l l o w in g e q u a t io n s ,w h ic h g iv e t h e r e l a t io n be t w e e n t h e po in t s C (x c ;0)a n d S (0;z s )in f u n c t io n o ft h el o c a t io n o ft h epo in t P (x p ;z p )on t h eo bj e c ta n d it s o r ie n t a t io n g iv e n b yt h ea n g l e °.If °6=45±,z s =¡f ¡t a n2°x c +f ¢t a n2°¢(H p +x p )¡f ¢x p x c+f ¡L (1)e l s e z =(H +x p )¢x c ¡f ¢x p +f ¡L (2)W e p r e s e n tb e l o win …g u r e 5b ,as im u l a t io n o ft h e r e l a t io n b e t w e e n t h epo in t s C a n d S c o r r e s po n d in gt o t h eo bj e c ts h a pes h o w n in …g u r e5a .-20-15-10-505101520-20-15-10-55101520-3-2-10123-400-300-200-100100200300Xc [mm]Zs [mm](a)Xp [mm]Zp [mm](b)F ig u r e5:a )r e p r e s e n t s t h eo bj e c ts h a pea n db )is t h ec o r r e s po n d in gpo in t -t o -po in tr e l a t io nb e t w e e nt h eCCD ma t r ixa n dt h el ig h t in gs y s t e mIn t h e…g u r ea bo v e ,t h epo in to n t h eCCD c a me r aa tt h el o c a t io n x c =1mm co r r e s po n d s r o u g h l yt ot h e po in to n t h e l ig h t in ga tt h e l o c a t io n z s =0mm.Sinc edef e c t s c h a ng e th e l o c a lo r ie n t a t io n °o ft h e o bj e c t s u r f a c e ,t h iss pe c i…cl o c a t io nint h el ig h t in gma yb ed i¤e r e n tw h e t h e rt h el u min o u s r a y se n c o u n t e rad e f e c t .In t h ec a s eo fape r f e c t l y‡a to bj e c tw it has ma l ld e f e c tmo d e l e db yaG a u s s ia nf u n c t io n ,w eo b t a int h ef o l l o w in g g r a p h (F ig u r e 6)g iv in gt h e c o r r e s po n d e n c e b e t w e e n a po in tC o n t h e CCD c a me r a a n d a po in tS’o n t h e l ig h t in gs y s t e m.T h epo in tS is t h ev ie w e dpo in to n t h el ig h t in gs y s t e m ift h e r ew e r en od e f e c t .-0.1-0.0500.050.10.15C Xs [mm]Area corresponding F ig u r e6:po in t -t o -po in tr e l a t io n f o raG a u s s ia nd e f e c tl o c a t e do n ap l a n er e ‡e c t iv eo bj e c tT h is p r e v io u s g r a p h s h o w s a s ig n i…c a n td i¤e r e n c e b e t w e e n t h e l o c a t io n s o ft h e po in t s S a n d S’.U s in ga l ig h t in gs y s t e m c o mpo s e d o fo n e t r a n s it io n o fl ig h t(i.e .l ig h t e d v e r s u s n o n -l ig h t e d ),po in t s C o n t h e o bj e c t s u r f a c e c o r r e s po n d in gt od e f e c t s w il lr e ‡e c tl u min o u s r a y s s u c h a s t h e y r e a c h a l ig h t e d a r e a o n t h e l ig h t in g s y s t e m w h il e o t h e rpo in t s a r e a s s o c ia t e d w it h n o n -l ig h t e d a r e a s .W e s h o win …g u r e t h e l o c a t io n s o ft h e l ig h tt r a n s it io n w it h r e s pe c tt ot h e d e f e c tl o c a t io n .F ig u r e 8g iv e s t h e l u min a n c e in f o r ma t io n v ie w e d b y t h e CCD c a me r af o rt h et w od i¤e r e n tl ig h tt r a n s it io n l o c a t io n s (1a n d 2in …g u r e7).T h e r e f o r e ,d e pe n d in gu po n t h e l ig h tt r a n s it io n l o c a t io n t h e d e f e c t s ma y a p pe a re it h e rw h it e o n ab l a c kb a c k g r o u n d o rb l a c ko n aw h it e b a c k g r o u n da s ith a s b e e n s h o w n in …g u r e3.-0.1-0.0500.050.10.15Location of the lighttransition Xc [mm]F ig u r e7:L o c a t io n s o ft h el ig h tt r a n s it io n w it h r e s pe c tt ot h ed e f e c tl o c a t io nLuminanceLuminance Xc [mm]0.05-0.050(a)(b)F ig u r e8:L u min a n c ef u n c t io n c a p t u r e db yt h ec a me r ac o r r e s po n d in gt ot h el ig h tt r a n s it io nl o c a t io n s g iv e n in …g u r e7s o l u t io n s h o w n in …g u r e9o n l ya l l o w s t h ep a r t ia ld e t e c t io n o fd e f e c t s l imit e d b y t h eb o l d a r r o w s ma r k e do u t int h is s a me10.T h is l e a d s t oa nin c o mp l e t ed e f e c td e t e c t io na n dd e f e c t s w o u l da p pe a rs ma l l e rt h a nt h e ya r e :i.e .t h e ire d g e s w o u l db ec o n t r a c t e da n dt h e irc e n t e rw o u l db ev ie w e din b l a c ka s w ec a n s e ein …g u r e11.2.2P r o p o s i t io no fa no p t im a ls o l u t io nT h er e s u l t so ft h es im u l a t io ns h o wt h a tino r d e rt od e t e c ta tl e a s tf e wp ix e l sb e l o n g in gt oad e f e c t ,t h eb l a c k s t r ipen e e d st ob es ma l l e rt h a nt h ed is t a n c eD n o t ic e dint h ep r e v io u s…g u r e .T h isd is t a n c ema yb ed e t e r min e d b y k n o w in gt h e ma x ima ld e f e c ts iz ea n du s in gt h er e l a t io n s h o w n in …g u r e9.H o w e v e r ,t h es e n s ib il it yo ft h e d e t e c t io n v a r ie s in f u n c t io n o ft h ed is t a n c ed e f e c tt ol ig h tt r a n s it io n :t h el a r g e ris t h eb l a c ks t r ipe ,t h ew o r s e is t h ed e t e c t io n ,s ot h a tav e r ys ma l ld e f e c tma yn o tb ed e t e c t e d .T h eo b v io u s s o l u t io nc o n s is t s in s e t t in gt h e s t r ipe w id t h s ot h a tt h e s ma l l e s td e f e c tt obe d e t e c t e d w o u l d b e o p t ima l l y d e t e c t e d :i.e .t h e d e f e c ts u r f a c e t e n d s t oama x im u m a s w es h o win …g u r e11.T h e p r e v io u s pr o po s e d s o l u t io n u s in gt w ob l a c k s t r ipe s l e a d s t oin c o mp l e t e d e f e c td e t e c t io n s in c e c e n t e r a n dbo u n d a r ie so fd e f e c t sa r eb a r e l yd e t e c t e d .Toa v o idt h ist h ea d e q u a t es o l u t io nc o n s is t sinu s in gt h ec a me r a s a t u r a t io n .T h es a t u r a t io n h a s t h ee ¤e c to fin c r e a s in ga n yw h it eb l o b s in ima g e s .T h er e s u l to fs u c ha n e ¤e c t is t h a tt h e d e f e c td e t e c t io n in w h it e a r e a s is n o tpo s s ib l e a n y mo r e ,b u tita l l o w s t h e c o mp l e t e d e t e c t io n in b l a c ka r e a s o fa l lt h ep ix e l s b e l o n g in gt oad e f e c t .T h u s ,t h er e t a in e dt e c h n ic a ls o l u t io nf o rd e t e c t in gd e f e c t s o nh ig h l yr e ‡e c t iv eo bj e c t s c o n s is t s ina n a l y z in g t h e r e ‡e c t io n o fa l ig h t in gs y s t e m c o mpo s e d o fl a r g e ,‡a tb a c k -l ig h ts y s t e m o n w h ic h a t h in o p a q u e s t r ipe h a s b e e np l a c e ds ot h a t ,b yu s in gt h ec a me r as a t u r a t io n d e f e c t s o p t ima l l ya ppe a rf r o m t h eb l a c kb a c k g r o u n d .W ed e s c r ib eint h ef o l l o w in gs e c t io na nin d u s t r ia la p p l ic a t io n o fq u a l it yc o n t r o lt h a tu s e s t h is s pe c i…cl ig h t in g-0.1-0.0500.050.10.15Lighting Zs [mm]Xc [mm]F ig u r e9:po in t -t o -po in tr e l a t io n s h o w in gt h ed e f e c tp a r t s d e t e c t e du s in gt w ol ig h tt r a n s it io n sF ig u r e10:D e f e c tc a p t u r e db yt h ec a me r au s in gt w ol ig h tt r a n s it io n s0102030Number of pixelsStripe width[mm]3D E F E C T S L O C A L IZ A T IO NT h ed e f e c tl o c a l iz a t io n s y s t e m,b a s e do n k n o w l e d g eo ft h el ig h t in g,is n o wp r e s e n t e d.A s d e s c r ibe da b o v e, t h e l ig h ts o u r c eis c o mpo s e d o fl u min o u s t r a n s it io n.In o r d e rt od e t e c td e f e c t s o n ac y l in d r ic a ls h a peo bj e c t, ith a s be e n d e t e r min e d b y e x pe r ime n t s t h a tt h e l ig h ts o u r c emu s tb ec o mpo s e d o ft h r e e s t r ipe s,o n ed a r kin t h e mid d l e o ft w oh ig h l y l u min o u s.T h e s e n s ib il it y o ft h es y s t e m is in c r e a s e d b y u s in gt h es a t u r a t io n o ft h e c a me r a a s itis d is c u s s e d in t h e p r e v io u s s e c t io n.Co n s e q u e n t l y d e f e c t s o n l y a p pe a r s in d a r k s t r ipe s a s itis s h o w n in…g u r e12.T h eima g in gpr o c e s s in gd e v e l o pe df o re x t r a c t in gd e f e c t sf r o m ima g e smin imiz e st h ep r o c e s s in gt imeino r d e r t oa l l o wt h e v is io n s y s t e m t oma k e af a s td e c is io n a b o u tt h e r e j e c t io n o fd e f e c t iv e p r o d u c t s.Sin c e p r o d u c t s o n t h e irs u p po r tma y b e in v a r io u s po s it io n s,t h e…r s to pe r a t io n c o n s is t s in d e…n in ga w o r k in gw in d o wt h a t l imit s t h er e g io n o fin t e r e s tin w h ic h d e f e c t s mig h tb ep r e s e n t.T h is w o r k in gw in d o wl o c a t io n(s e e…g u r e12) is s ot h a titis a b o v et h epr o d u c ts u p po r t s,b e l o wt h ep r o d u c tt o p s,a n d it s s id e s a r ed e…n e d b yk n o w in gt h e o bj e c ts iz e.T h es u p po r t s a r ee a s il yd e t e c t a b l es in c et h e y k e e p t h es a mes h a pef o ra n yk in d o fp r o d u c tt ob e c o n t r o l l e d.T h es u p po r t s a p pe a rin t h el o w e rp a r to ft h eima g epr e s e n t e din…g u r e12.T h ef o l l o w in gima g ep r o c e s s in gc o n s is t s in…l t e r in gt h eima g eino r d e rt or e mo v et h en o is et h a tma yr e n d e r t h e d e f e c td e t e c t io n p r o c e s s in e¢c ie n t.A s mo o t h in ga l g o r it h m is u s e d f o rt h is p u r po s e.T h e l a s ta l g o r it h m a l l o w st h ed e t e c t io no ft h en u m b e ro fs t a t is t ic a lmo d e sin c l u d e dine a c hh o r iz o n t a lc r o s s-s e c t io no ft h eima g ea s w es e ein…g u r e13.T h ec r o s s-s e c t io na n a l y s is in d ic a t e s ad e f e c tift h r e es t a t is t ic a lmo d e s a r ec o u n t e d,in s t e a d o ft w omo d e s w it h o u td e f e c t.T h e mo d e c o u n t in gme t h o d is pe r f o r me d b y c o u n t in gt h e n u mb e ro fin‡e x io n po in t s in t h e s ig n a lo b t a in e d a f t e rt h e d e r iv a t io n o ft h e c r o s s-s e c t io n s ig n a l.P ix e l s b e l o n g in g t o d e f e c t s a r e e x t r a c t e d,a n dt h e nl a b e l l e dd u r in gt h is o pe r a t io n.F ig u r e14p r e s e n t s t h er e s u l to ft h el o c a l iz a t io npr o c e s s o f d e f e c t s.4C O M P L E T E IN D U ST R IA L SY ST E M T h ep r o d u c t s be in gc o n t r o l l e d a r er o t a t e dw h il ep a s s in gin f r o n to ft h ec a me r ain o r d e rt oa l l o wt h e irf u l l c o n t r o l.To d e c id e w h e t h e ro rn o ta p r o d u c tis d e f e c t iv e,t h e p ix e l s e x t r a c t e d f r o m e a c h w o r k in g w in d o w s a r e t h e n l a b e l e d.E a c h p ix e lb e l o n g in gt ot h e s a me d e f e c tw il lg e tt h e s a me l a b e l.T h e n u mb e ro fp ix e l s o f e a c h d e f e c ta n d t h e n u m b e ro fd e f e c t s a r e s t o r e d f o re a c h p r o d u c ta s itmo v e s in f r o n to ft h e c a me r a.T h is in f o r ma t io n is t h e n u s e d t oma k ead e c is io n a bo u tt h e q u a l it y o ft h e p r o d u c tb y c o mp a r in gitt oa c c e p t a n c e t h r e s h o l d s p r e v io u s l y d e c id e d b y t h e q u a l it y c o n t r o ld e p a r t me n t.T h e v is io n s y s t e m is e n d e d b y a p r o d u c t e x t r a c t io n mo d u l et h a te j e c t e s d e f e c t iv ep r o d u c t s f r o m t h ep r o d u c t io n l in e.T h ed e s c r ibe da u t o ma t e dt o o l,p r e s e n t e din…g u r e??,pe r f o r ms t h eq u a l it yc o n t r o lo fr e‡e c t iv ec y l in d r ic a l p r o d u c t sa tar a t eo fo n ep r o d u c tpe rs e c o n d.P r o d u c td is p l a c e me n ts pe e dise q u iv a l e n tt o5me t e r spe rmin u t e.A l lt h ep a r a me t e r s g iv e na b o v ea r el in k e dt op r o d u c t io nc o n s t r a in t s.T h is s y s t e m h a s be e nimp l e me n t e do n a 133M H z P C c o n n e c t e dt oaP CI f r a meg r a b be r.A s o f t w a r eh a s b e e n d e v e l o pe din b o t h a s s e m b l ya n dC++.D e f e c tl o c a l iz a t io n is ma d eo n d a t a‡o wa tt h er a t eo f50ima g e s pe rs e c o n d.F ig u r e15:Co mp l e t ein d u s t r ia ls y s t e mF ig u r e12:E x a mp l eo ff e wd e f e c t iv ep r o d u c t sF ig u r e13:a)H o r iz o n t a lc r o s s-s e c t io n in t h e ima g e w h e r e t h e r e is n od e f e c t.b)Cr o s s-s e c t io n in t h e ima g e w h e r et h e r eis ad e f e c t.5C O N C L U SIO NT h ea im o ft h is w o r kw a s t or e a l iz e da na u t o ma t e dq u a l it yc o n t r o lt o o lf o rw h ic ht h ek e yc o mpo n e n tis t h e r e a lt imec o n t r o lo fh ig h l yr e‡e c t iv e3do bj e c t s.T o r e a c h t h is g o a l,a s pe c i…c l ig h t in gs y s t e m h a s b e e n d e s ig n e d a n d a g e o me t r ic a lmo d e la l l o w e d u s t o d e…n e t h e o p t ima ls e to fp a r a me t e r s o ft h e v is io n s y s t e m s u c h a s t h e l o c a t io n o ft h e c a me r a w it h r e s pe c t t o t h e p r o d u c tt o be c o n t r o l l e d,a n d mo r e impo r t a n t l y,t h e o p t ima lc h a r a c t e r is t ic s o ft h e l ig h t in g s y s t e m.B a s e d o n t h is s t u d y,a t e c h n ic a ls o l u t io n f o rc o n t r o l l in gmo v in gr e‡e c t iv e o bj e c t s h a s be e n p r o po s e d.F a s t ima g ep r o c e s s in gh a v eb e e nd e v e l o pe da l l o w in gt h ec o mp u t a t io no fr e l e v a n tp a r a me t e r s s u c ha s t h en u m b e ro f d e t e t e d d e f e c t s a 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