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Dear all—I propose to this article a new section entitled "Extension to non-line-of-sight surfaces".
![]() | This edit request by an editor with a conflict of interest was declined. A reviewer felt that this edit would not improve the article. |
Photometric stereo can be extended to scenarios where the object of interest is not in line of sight from the observer. [1] In this so-called "looking around the corner" (or non-line-of-sight-imaging) setting, the object of interest can only be observed indirectly via some diffuse (non-mirror-like) relay wall. To measure the surface orientations of the hidden object, a light source such as pulsed laser illuminates a known location on the diffuse wall and some of the light bounces off the wall, propagates to the hidden object and eventually back to the photodetector co-located with the light source. By probing multiple locations on the diffuse wall and recording the number of photons detected as a function of time, one can construct a 3D, spatio-temporal volume of photon measurements from which the surface orientations of the hidden object can be reconstructed computationally.
Due to the presence of the diffuse wall in the observation model, recovering the surface normals of the hidden involves performing a deconvolution in addition to solving a three by three system of linear equations at each pixel similarly to the basic method. The overall inverse problem can be solved using Cholesky–Wiener decomposition with computational complexity linear in the number of voxels. However, in contrast with the basic method above, the non-line-of-sight variant of photometric stereo operates on a three-dimensional volume of measurements, rendering the technique more computationally demanding. Also, in practice, the signal-to-noise ratio of the recovered surface orientations is proportional to the output power of the light source (e.g. pulsed laser), which can be a limitation considering potential safety issues associated with operating high-power lasers.
Just like non-Lambertian surfaces, inverse rendering of non-line-of-sight surfaces is a problem of general interest within the graphics community. Please have a look at the reverted edit for its wider relevance.
MrOllie has kindly pointed out that there may be potential self-promotion in my recent edit (which he has reverted since). So I suggest that this review article be referenced instead: https://www.nature.com/articles/s42254-020-0174-8 .
References
![]() | This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
Dear all—I propose to this article a new section entitled "Extension to non-line-of-sight surfaces".
![]() | This edit request by an editor with a conflict of interest was declined. A reviewer felt that this edit would not improve the article. |
Photometric stereo can be extended to scenarios where the object of interest is not in line of sight from the observer. [1] In this so-called "looking around the corner" (or non-line-of-sight-imaging) setting, the object of interest can only be observed indirectly via some diffuse (non-mirror-like) relay wall. To measure the surface orientations of the hidden object, a light source such as pulsed laser illuminates a known location on the diffuse wall and some of the light bounces off the wall, propagates to the hidden object and eventually back to the photodetector co-located with the light source. By probing multiple locations on the diffuse wall and recording the number of photons detected as a function of time, one can construct a 3D, spatio-temporal volume of photon measurements from which the surface orientations of the hidden object can be reconstructed computationally.
Due to the presence of the diffuse wall in the observation model, recovering the surface normals of the hidden involves performing a deconvolution in addition to solving a three by three system of linear equations at each pixel similarly to the basic method. The overall inverse problem can be solved using Cholesky–Wiener decomposition with computational complexity linear in the number of voxels. However, in contrast with the basic method above, the non-line-of-sight variant of photometric stereo operates on a three-dimensional volume of measurements, rendering the technique more computationally demanding. Also, in practice, the signal-to-noise ratio of the recovered surface orientations is proportional to the output power of the light source (e.g. pulsed laser), which can be a limitation considering potential safety issues associated with operating high-power lasers.
Just like non-Lambertian surfaces, inverse rendering of non-line-of-sight surfaces is a problem of general interest within the graphics community. Please have a look at the reverted edit for its wider relevance.
MrOllie has kindly pointed out that there may be potential self-promotion in my recent edit (which he has reverted since). So I suggest that this review article be referenced instead: https://www.nature.com/articles/s42254-020-0174-8 .
References