5. 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
12. 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.
13. 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.
14. 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
15. 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.
16. 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
17. MIT Media Lab
Camera Culture
Other Applications
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Manufacturing
Automation
Robotic navigation.
Rumoured to being developed for phones so
the sky is the limit.
Editor's Notes
Currentcolor imaging technology only provides clues about the depth in the scene. Only social cues like the size of objects and shadows.
Time of flight cameras measure the depth for each pixel. This is an example figure from a time of flight camera. Each pixel is located in X,Y,Z in space. Person infront of the scene.
Phase translates to distance. Measure phase because measuring direct time of flight is hard.
Really say that four frames are required. Say something about motion.
Talk about the noise. The black table cloth returns less light therefore is more noisy.
Say the modulation frequency is the length of the pulse. The shorter the pulse the more precision the measurements however phase wrapping.
Add comments about mixed pixels.
Talk about how we are exploring other areas for ToF. Medical imaging.