Moving Basis Decomposition for Precomputed Light Transport

2021 ◽  
Vol 40 (4) ◽  
pp. 127-137
Author(s):  
Ari Silvennoinen ◽  
Peter‐Pike Sloan

2020 ◽  
Vol 2020 (14) ◽  
pp. 357-1-357-6
Author(s):  
Luisa F. Polanía ◽  
Raja Bala ◽  
Ankur Purwar ◽  
Paul Matts ◽  
Martin Maltz

Human skin is made up of two primary chromophores: melanin, the pigment in the epidermis giving skin its color; and hemoglobin, the pigment in the red blood cells of the vascular network within the dermis. The relative concentrations of these chromophores provide a vital indicator for skin health and appearance. We present a technique to automatically estimate chromophore maps from RGB images of human faces captured with mobile devices such as smartphones. The ultimate goal is to provide a diagnostic aid for individuals to monitor and improve the quality of their facial skin. A previous method approaches the problem as one of blind source separation, and applies Independent Component Analysis (ICA) in camera RGB space to estimate the chromophores. We extend this technique in two important ways. First we observe that models for light transport in skin call for source separation to be performed in log spectral reflectance coordinates rather than in RGB. Thus we transform camera RGB to a spectral reflectance space prior to applying ICA. This process involves the use of a linear camera model and Principal Component Analysis to represent skin spectral reflectance as a lowdimensional manifold. The camera model requires knowledge of the incident illuminant, which we obtain via a novel technique that uses the human lip as a calibration object. Second, we address an inherent limitation with ICA that the ordering of the separated signals is random and ambiguous. We incorporate a domain-specific prior model for human chromophore spectra as a constraint in solving ICA. Results on a dataset of mobile camera images show high quality and unambiguous recovery of chromophores.



2015 ◽  
Vol 91 (5) ◽  
Author(s):  
A. S. Sheremet ◽  
D. F. Kornovan ◽  
L. V. Gerasimov ◽  
B. Gouraud ◽  
J. Laurat ◽  
...  


2020 ◽  
Vol 39 (3) ◽  
pp. 1-14 ◽  
Author(s):  
Damien Rioux-Lavoie ◽  
Joey Litalien ◽  
Adrien Gruson ◽  
Toshiya Hachisuka ◽  
Derek Nowrouzezahrai


2021 ◽  
Vol 126 (22) ◽  
Author(s):  
Xingda Lu ◽  
Wanxia Cao ◽  
Wei Yi ◽  
Heng Shen ◽  
Yanhong Xiao




2012 ◽  
Vol 31 (4) ◽  
pp. 1-11 ◽  
Author(s):  
Matthew O'Toole ◽  
Ramesh Raskar ◽  
Kiriakos N. Kutulakos


2014 ◽  
Vol 33 (4) ◽  
pp. 1-11 ◽  
Author(s):  
Jiří Vorba ◽  
Ondřej Karlík ◽  
Martin Šik ◽  
Tobias Ritschel ◽  
Jaroslav Křivánek


2010 ◽  
Vol 03 (02) ◽  
pp. 91-102 ◽  
Author(s):  
TING LI ◽  
HUI GONG ◽  
QINGMING LUO

The Monte Carlo code MCML (Monte Carlo modeling of light transport in multi-layered tissue) has been the gold standard for simulations of light transport in multi-layer tissue, but it is ineffective in the presence of three-dimensional (3D) heterogeneity. New techniques have been attempted to resolve this problem, such as MCLS, which is derived from MCML, and tMCimg, which draws upon image datasets. Nevertheless, these approaches are insufficient because of their low precision or simplistic modeling. We report on the development of a novel model for photon migration in voxelized media (MCVM) with 3D heterogeneity. Voxel crossing detection and refractive-index-unmatched boundaries were considered to improve the precision and eliminate dependence on refractive-index-matched tissue. Using a semi-infinite homogeneous medium, steady-state and time-resolved simulations of MCVM agreed well with MCML, with high precision (~100%) for the total diffuse reflectance and total fractional absorption compared to those of tMCimg (< 70%). Based on a refractive-index-matched heterogeneous skin model, the results of MCVM were found to coincide with those of MCLS. Finally, MCVM was applied to a two-layered sphere with multi-inclusions, which is an example of a 3D heterogeneous media with refractive-index-unmatched boundaries. MCVM provided a reliable model for simulation of photon migration in voxelized 3D heterogeneous media, and it was developed to be a flexible and simple software tool that delivers high-precision results.



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