Authors:
Ruri Oya
;
Ryo Matsuoka
and
Takahiro Okabe
Affiliation:
Department of Artificial Intelligence, Kyushu Institute of Technology, Japan
Keyword(s):
Light Source Separation, Alternating Current, Flicker, NMF, ICA.
Abstract:
Artificial light sources powered by an electric grid change their intensities in response to the grid’s alternating current (AC). Their flickers are usually too fast to notice with our naked eyes, but can be captured by using cameras with short exposure time settings. In this paper, we propose a method for light source separation under AC illumination on the basis of Blind Source Separation (BSS). Specifically, we show that light source separation results in matrix factorization, since the input images of a scene illuminated by multiple AC light sources are represented by the linear combinations of the basis images, each of which is the image of the scene illuminated by only one of the light sources, with the coefficients, each of which is the intensity of the light source. Then, we make use of Non-negative Matrix Factorization (NMF), because both the pixel values of the basis images and the intensities of the light sources are non-negative. We experimentally confirmed that our metho
d using NMF works better than Independent Component Analysis (ICA), and studied the performance of our method under various conditions: varying exposure times and noise levels.
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