TR2008-028

Non-Refractive Modulators for Encoding and Capturing Scene Appearance and Depth

    •  Veeraraghavan, A., Agrawal, A., Raskar, R., Mohan, A., Tumblin, J., "Non-Refractive Modulators for Encoding and Capturing Scene Appearance and Depth", IEEE Conference on Computer Vision and Pattern Recognition (CVPR), June 2008.
      BibTeX TR2008-028 PDF
      • @inproceedings{Veeraraghavan2008jun,
      • author = {Veeraraghavan, A. and Agrawal, A. and Raskar, R. and Mohan, A. and Tumblin, J.},
      • title = {Non-Refractive Modulators for Encoding and Capturing Scene Appearance and Depth},
      • booktitle = {IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
      • year = 2008,
      • month = jun,
      • url = {https://www.merl.com/publications/TR2008-028}
      • }
  • Research Area:

    Computer Vision

TR Image
(a) CapturedModulated Image (b) Refocussed Image-Focus in Front (c) Refocussed Image-Focus on the back end (d) Raw Depth labels quantized to 10 depth levels. (e) All in focus image.Supplemental material have additional results including refocussing videos and matlab code.
Abstract:

We analyze the modulation of a light field via non-refracting attenuators. In the most general case, any desired modulation can be achieved with attenuators having four degrees of freedom in ray-space. We motivate the discussion with a universal 4D ray modulator (ray-filter) which can attenuate the intensity of each ray independently. We describe operating of such a fantasy ray-filter in the context of altering the 4D light field incident on a 2D camera sensor.

Ray-filters are difficult to realize in practice but we can achieve reversible encoding for light field capture using patterned attenuating mask. Two mask-based designs are analyzed in this framework. The first design closely mimics the angle-dependent ray-sorting possible with the ray filter. The second design [17] exploits frequency-domain modulation to achieve a more efficient encoding. We extend these designs for optimal sampling of light field by matching the modulation function to the specific shape of the band-limit frequency transform of light field. We also show how a hand-held version of an attenuator based light field camera can be built using a medium-format digital camera and an inexpensive mask.

 

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      Date: June 28, 2008
      Where: IEEE Conference on Computer Vision and Pattern Recognition (CVPR)
      MERL Contacts: Matthew Brand; Anthony Vetro
      Brief
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