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arXiv · 1609.04079

Single-image RGB Photometric Stereo With Spatially-varying Albedo

Ayan Chakrabarti·Kalyan Sunkavalli
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Abstract

We present a single-shot system to recover surface geometry of objects with spatially-varying albedos, from images captured under a calibrated RGB photometric stereo setup---with three light directions multiplexed across different color channels in the observed RGB image. Since the problem is ill-posed point-wise, we assume that the albedo map can be modeled as piece-wise constant with a restricted number of distinct albedo values. We show that under ideal conditions, the shape of a non-degenerate local constant albedo surface patch can theoretically be recovered exactly. Moreover, we present a practical and efficient algorithm that uses this model to robustly recover shape from real images. Our method first reasons about shape locally in a dense set of patches in the observed image, producing shape distributions for every patch. These local distributions are then combined to produce a single consistent surface normal map. We demonstrate the efficacy of the approach through experiments on both synthetic renderings as well as real captured images.

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Ayan Chakrabarti, Kalyan Sunkavalli. 2016-09-14. Single-image RGB Photometric Stereo With Spatially-varying Albedo. https://arxiv.org/abs/1609.04079

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