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High Dynamic Range Imaging Using a Plenoptic Camera

Abstract:

Light field (or plenoptic) imaging has become an attractive research field due to its post-capture capabilities, including refocusing, perspective change and depth estimation. Micro-lens array based cameras that recently emerged have made the light field acquisition process a practical task. In this paper, we propose to convert such a plenoptic camera into a high-dynamic range camera through a minor optical modification. The optical modification is an optical mask placed in front of the main lens to increases the vignetting effect, which darkening towards the borders of the image plane due to loss of light. As a result, different parts of the dynamic range are captured with different sub-aperture images of the light field. These sub-aperture images are then fused through photometric registration and optical flow vectors to produce a high-dynamic range image.

Publication(s):

"High dynamic range imaging using a plenoptic camera,"
Abdul Wahab, M Zeshan Alam and Bahadir K Gunturk,
Proceedings of 25th IEEE Signal Processing and Communication Application Conference (SIU), 2017 ,
[PDF]

Funding:

TUBITAK grant 1003

Images:

Optical setup.

Schematic of the optical setup.

 (Left) High exposure image. (Right) Low exposure image. (Bottom) HDR image.
 (Left) HDR image without optical mask. (Right) HDR image with optical mask.
Comparison between the histograms of the HDR images. (Left) Without optical mask. (Right) With optical mask.
 (Left) Captured light field. (Right) HDR light field.
(Left) High exposure image. (Right) Low exposure image. (Bottom) HDR image.
Post-capture digital refocusing. (Left) Close-depth refocus. (Middle) Mid-depth refocus. (Right) Far-depth refocus.
Post-capture digital refocusing. Zoomed-in regions from Figure 8 are shown. (Left column) Close-depth refocus. (Middle column) Mid-depth refocus. (Right column) Far-depth refocus.