Image Sensor Technologies for 3D Time-of-flight …

1 Image Sensor Technologies for 3D Time-of-flight Range ImagingThierry OggierBergen, 2009 TOF TechnologiesContent Overview 3D Technologies How does a 3D TOF demodulation pixel work? Why is a 3D TOF pixel 100 times bigger than state-of-the art CCD / CMOS pixel ? Why does a 3D TOF pixel require extremely high-speed electrontransfer? Overview of state-of-the-art 3D TOF pixel implementations Summary / OutlookOverview 3D TechnologiesComparisonDistance MeasuringTechnologyTriangulation(geometr ical measurement)Active(light source and receiver)Passive (two receivers) Time-of-flight (TOF)(optical modulation)Pulsed TOF(SPAD.)

2 CW Measurement(lock-in)Interferometry(optic al coherence)Overview 3D TechnologiesComparisonTriangulation(geom etricalmeasurement) Time-of-flight (TOF)(o ptical modulation)Interferometry(optical coherence)Range R0 Basis dependent mm toa few mR0 c/F cm to 100mR0 mDepthnoise R2 R Requiredcomputing power-++Miniaturizationpotential-+-Econo micpotential-+-OtherPassive:Texture requiredOverview 3D TechnologiesComparisonApplication Range [m]Resolution [m]10-310010-610310-910-610-31003D TOF ImagingAcquisition SamplesTOF TechnologiesHow does a 3D TOF pixel work?TOF TechnologiesHow does a 3D TOF pixel work?

3 --=2013atan AAAAj43210 AAAAB+++=[] []2220213 AAAAA-+-= Amplitude / Quality Intensity / BW Phase / DistanceTOF TechnologiesHow does a 3D TOF pixel work?Main challenges for3D TOF pixelsTOF TechnologiesWhy a 3D TOF pixel requires high-speed?ndiffusionDxt2=DdxdUuxEuxtnnd rift/22 = -=DElectron Transfer Time:Device Simulation:VUmxdrift27=D=mTOF TechnologiesWhy a 3D TOF pixel requires high-speed?System SimulationTOF TechnologiesWhy are 3D TOF Pixels that big?Note: Modulation at 20 MHz Ideal imager(perfect demodulation, nosaturation, no noise) No background light Phyiscal limitation(photon shot noise limit) 10mm standard deviationrequires ~ 20ke- / sampleTOF TechnologiesWhy are 3D TOF Pixels that big?

4 Assumption: Camera with 1W/m2 on target(typical for a target at 1m) Sun light ~50W/m2 Note: Modulation at 20 MHz Ideal imager(perfect demodulation, nosaturation, no noise) Physical limitation(photon shot noise limit) 10mm standard deviationrequires close to 1Me / tapmodulated and dealing with30Me- backgroundTOF TechnologiesImplementations (Canesta)*Gokturket al, A Time-of-flight Depth Sensor -System Description, Issues and Solutions , CVPR 04, , TOF TechnologiesImplementations (PMD Technology)*Hagebeuker, Mehrdimensionale Objekterfassung mittels PMD Sensorik , Optik & Photonik, March 08 TOF TechnologiesImplementations (University Shizuoka)

5 *Kawahitoet al, A CMOS Time-of-flight range Image Sensor with gates-on-field-oxide structure ; IEEE Sensors Journal, Vol. 7, No. 12, Dec 2007 TOF TechnologiesImplementations (Vrejie University Brussels)*D. Van Nieuwenhoveet al, Novel Standard CMOS Detector using Majority Current for guiding Photo-Generated Electrons towards Detecting Junctions ,Proceedings Symposium IEEE/LEOS Benelux Chapter, 2005, Mons*B. B ttgen et al, Demonstration of a Novel Drift Field pixel Structure for the Demodulation of Modulated Light Waves with Application in Three-Dimensional Image Capture , SPIE Proc.

6 Vol. 5302 (2004)TOF TechnologiesImplementations (MESA / CSEM)TOF TechnologiesSummary / Outlook Interferometry, triangulation and TOF Technologies offer approachesfor different ranges and resolutions. Biggest challenges for TOF pixel : the high-speed demodulation the required high dynamic range Compared to standard pixels, TOF pixel are much larger and have a lower fill factor. First industrial-grade TOF camera on the market in 2009. High volume applications represent interesting opportunity for TOF you for your