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MIT Media Lab Camera Culture Introduction to Time-of-Flight
Range Imaging Refael Whyte
MIT Media Lab Camera Culture Why Depth? Color photos have
limited depth information
MIT Media Lab Camera Culture Time-of-Flight Cameras 18 October
2013 THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 3
MIT Media Lab Camera Culture Measuring Distance Illuminate
scene with amplitude modulated light. Phase difference between
transmitted and reflected light encodes distance. Transmitted and
returning light is correlated to measure distance. 18 October 2013
THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 4
MIT Media Lab Camera Culture Measuring Distance Returning light
is correlated with reference waveform. Reference waveform is phase
shifted Measured points fit a sine wave. 5
MIT Media Lab Camera Culture Correlation Function
MIT Media Lab Camera Culture Measuring Distance
MIT Media Lab Camera Culture Real Data Measured correlation
waveform of one pixel Compute phase and amplitude from FFT.
MIT Media Lab Camera Culture Camera Data Phase and amplitude
images, 120x160 sensor.
MIT Media Lab Camera Culture Measurement Errors
MIT Media Lab Camera Culture Multipath Multiple propagation
paths. In scene paths and lens flare effects. Still an unsolved
problem. Use low reflective material around objects of interest to
mitigate 18/10/2013 THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O
WAIKATO 11
MIT Media Lab Camera Culture Multipath The measured pixels
value is the sum of both components on the complex plane. Reflect
table tops and floors can see reflection in the amplitude
image.
MIT Media Lab Camera Culture Other Sources Temperature drift.
Jitter. Jitter in the modulation signal limits precision. Photon
shot noise in pixel structure. Is assumed to be an independent
guassian noise source. Readout noise. Noise added by ADC and
readout process. Harmonic aliasing impacts accuracy.
MIT Media Lab Camera Culture Time-of-Flight at MIT Access to
commercial Time of flight cameras and custom built ones Commercial
ones from: Softkinetic, PMD and Mesa Imaging
MIT Media Lab Camera Culture Coke Bottle Light Sweep
Visualization of light in a coke bottle
http://www.youtube.com/watch?v=fSqFWcb4rE Light sweep with ToF
Camera https://sites.google.com/site/tofvid/ Similar results 1000x
reduction in cost of hardware.
MIT Media Lab Camera Culture Time of Flight Applications Next
generation Kinect for Xbox One.
http://www.youtube.com/watch?v=Hi5kMNfgDS 4 Object Scanning
http://www.youtube.com/watch?v=IXr9zqz6Bjc Hand tracking
http://www.youtube.com/watch?v=Qj4ymzTNw Dw Other
http://www.youtube.com/watch?v=eAlSfEqBBhM
MIT Media Lab Camera Culture Other Applications Manufacturing
Automation Robotic navigation. Rumoured to being developed for
phones so the sky is the limit.