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Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
Survey of tof and imaging systems
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Survey of tof and imaging systems

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  • 1. Survey of IR/TOF/3D Imaging SSyysstteemmss Manu Suryavansh 4/18/2012
  • 2. Topics • History and Present – – LIDAR – Lock-In amplifier and pixel – CCD –– CCMMOOSS IImmaaggeerrss – Infrared communication System – IRDA – TOF and 3D Imaging – SAPD • Some major companies -
  • 3. Depth/Range Sensor Applications • 3D Imaging • Gaming • Auto Focus in Digital camera •• OObbjjeecctt ddeetteeccttiioonn • Robotics
  • 4. Distance/Depth Measurement Techniques Contactless distance measurement Triangulation Interferometry Time of Flight Pulse Continuous Wave Modulation
  • 5. TOF Techniques
  • 6. Depth/TOF Techniques - Triangulation • Determine the depth of a single point in the scene. • Used in sharp analog distance sensor (20 – 150 cm range)
  • 7. Depth/TOF Techniques - Passive Stereoscopy • Single point depth estimation using two cameras.
  • 8. Living Images – Light Field Camera/Plenoptic Camera • Recently released to market by Lytro. • It uses a microlens aarrrraayy ttoo ccaappttuurree 44DD light field. • Depth information can also be extracted. • Pictures can be focused after they are taken!!
  • 9. Time of Flight - Wikipedia • Applications – – Calculate Electron mobility – Mass spectrometry – Near Infrared spectroscopy – pprrooppeerrttyy ooff mmaatteerriiaall – Ultrasonic flow meter - velocity of fluids – 3D Imaging/Depth Sensor
  • 10. TOF -1 Complex and Big Vs Demodulating Pixel Ref – Canesta Inc – 2004 IEEE Computer Society
  • 11. Basic 3D TOF Imaging Principle
  • 12. Phase Measurment
  • 13. Simple Demodulating Pixel Reference - Industrial Robot Journal
  • 14. Demodulating IR Pixel • Sending two pulses with 0 and 90 degree phase. • Performing DFT on the demodulated to get pphhaassee..
  • 15. Noise Sources in photo detectors
  • 16. CMOS Imager
  • 17. CMOS Active Pixel Structure (APS) • Color Image Sensor consists of a photo sensor and a color filter. • There are three types of photo sensors – photodiode, bipolar phototransistor and photo FFEETT.. • There are several types of color filters like – Bayer sensor, Foveon X3 Sensor etc. • Amplifier • CMOS Imagers have relatively very small pixels (5um x 5um and even smaller).
  • 18. SAPD – Single Photon Avalanche Photodetector Camera • An avalanche photodiode (APD) is a highly sensitive semiconductor electronic device that exploits the photoelectric effect to convert light to electricity –– WWiikkiippeeddiiaa..
  • 19. Lock-In Amplifier/System • A lock-in amplifier system takes a periodic reference signal and a noisy signal as input signals to a phase sensitive detector. • Reference Signal – rr((tt))==ssiinn((22**ppii**ffoo**tt)) • Input Signal – i(t)=Asin(2*pi*fo*t + Q) + n(t) • Output – P(t) = r(t)*i(t) = ½Acos(Q) - other
  • 20. LOCK-In CCD/Photodiode • The lock-in CCD is based on synchronous photo charge detection and storage. • Using 4 samples offset, phase and amplitude ccaann bbee ddeetteerrmmiinneedd.. • Integration time – d1
  • 21. Single Pixel TOF Single Pixel + Demodulator Gain ADC DFT/FFT
  • 22. TOF Cont
  • 23. Pixel ADC using SDM Digital/Analog CDS can be used to cancel Ambient light/noise.
  • 24. Example - A Range Image Sensor Based on 10-μm Lock-In Pixels in 0.18μm CMOS Imaging Technology – ISSCC-2010 Ref – D. Stoppa – ISSCC-2010
  • 25. Example -1, cont
  • 26. Example2 – A 16x16 Pixel Distance sensor with In-Pixel circuitry that tolerates 150klx of ambient light – JSSC-2010-Gerald Zach • Range – 0 to 3.2m • Standard deviation – few cm’s • Linearity error -> +/-2cm • Process –– 00..66uumm BBiiCCMMOOSS • Pixel size – 16um x 16um • Illumination source – 4 LED’s of 850nm • Power Consumption – 10W
  • 27. Example2- cont.
  • 28. Some companies working on TOF/3D – Canesta/Microsoft – Primesense – SoftKinetic –– PPMMDDTTeecchh – Mesa Imaging
  • 29. PMDVision- CamBoard Nano
  • 30. Infrared Remote Control Systems Vishay/Sharp makes parts like these Carrier Frequency – 30KHz to 56KHz Wavelength – 940nm
  • 31. Wireless Infrared Communications IrDA supports 4Mb/s data rate. Cmos Optical Preamplifier with ambient light cancellation- Ref – Phang and Johns – IEEE-1999
  • 32. Ambient Light Cancellation - 1993 Wally did this app note almost 20 years ago!
  • 33. Ultrasonic TOF Based depth sensor • Time based as speed of sound travels much slower.

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