Moving Basis Decomposition for Precomputed Light Transport

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

Skin Chromophore Estimation from Mobile Selfie Images using Constrained Independent Component Analysis

2020 ◽  
Vol 2020 (14) ◽  
pp. 357-1-357-6
Author(s):  
Luisa F. Polanía ◽  
Raja Bala ◽  
Ankur Purwar ◽  
Paul Matts ◽  
Martin Maltz
Keyword(s):  
Independent Component Analysis ◽  
Spectral Reflectance ◽  
Source Separation ◽  
Principal Component ◽  
Component Analysis ◽  
Previous Method ◽  
Independent Component ◽  
Light Transport ◽  
Camera Model ◽  
Constrained Independent Component Analysis

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.

scholarly journals Coherent control of light transport in a dense and disordered atomic ensemble

2015 ◽  
Vol 91 (5) ◽  
Author(s):  
A. S. Sheremet ◽  
D. F. Kornovan ◽  
L. V. Gerasimov ◽  
B. Gouraud ◽  
J. Laurat ◽  
...  
Keyword(s):  
Coherent Control ◽  
Light Transport ◽  
Atomic Ensemble

Delayed Rejection Metropolis Light Transport

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

scholarly journals Nonreciprocity and Quantum Correlations of Light Transport in Hot Atoms via Reservoir Engineering

2021 ◽  
Vol 126 (22) ◽  
Author(s):  
Xingda Lu ◽  
Wanxia Cao ◽  
Wei Yi ◽  
Heng Shen ◽  
Yanhong Xiao
Keyword(s):  
Quantum Correlations ◽  
Light Transport ◽  
Reservoir Engineering

Light transport in three-dimensional photonic crystals

Nano-Optics ◽  
2020 ◽  
pp. 197-226
Author(s):  
Rajesh V. Nair
Keyword(s):  
Photonic Crystals ◽  
Three Dimensional ◽  
Light Transport

scholarly journals Primal-dual coding to probe light transport

2012 ◽  
Vol 31 (4) ◽  
pp. 1-11 ◽  
Author(s):  
Matthew O'Toole ◽  
Ramesh Raskar ◽  
Kiriakos N. Kutulakos
Keyword(s):  
Light Transport ◽  
Dual Coding ◽  
Probe Light ◽  
Primal Dual

On-line learning of parametric mixture models for light transport simulation

2014 ◽  
Vol 33 (4) ◽  
pp. 1-11 ◽  
Author(s):  
Jiří Vorba ◽  
Ondřej Karlík ◽  
Martin Šik ◽  
Tobias Ritschel ◽  
Jaroslav Křivánek
Keyword(s):  
Mixture Models ◽  
Light Transport ◽  
Transport Simulation ◽  
On Line ◽  
On Line Learning ◽  
Light Transport Simulation

MCVM: MONTE CARLO MODELING OF PHOTON MIGRATION IN VOXELIZED MEDIA

2010 ◽  
Vol 03 (02) ◽  
pp. 91-102 ◽  
Author(s):  
TING LI ◽  
HUI GONG ◽  
QINGMING LUO
Keyword(s):  
Monte Carlo ◽  
Refractive Index ◽  
High Precision ◽  
Heterogeneous Media ◽  
Homogeneous Medium ◽  
Software Tool ◽  
Light Transport ◽  
Photon Migration ◽  
Monte Carlo Code ◽  
Monte Carlo Modeling

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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