Noiseless no-flash photo creation by color transform of flash image
Keiichiro Shirai, Masayuki Okamoto, Masaaki Ikehara · 2011
In the dark place photographing, the increase of noise is one of the major problems to be addressed. Although using a flash is effective to reduce the noise, natural colors are faded away due to increase of specular lights. In this paper, we present a method that generates a no-flash like flash image by approximating colors of a flash image by those of a no-flash image. Our method is based on the ”color-line” feature of images, a linear distribution of colors in a local region is transformed by a set of transform matrices automatically. This method is able to deal correctly with the occluded regions where the colors are saturated by reflections or shadows and the color distribution is squashed.