Digital cameras are used under a wide spectrum of illuminants and should adjust the white point according to the illuminant used (white balance correction). The white balance correction makes "white" object be reproduced as "white" but the reproduction of chromatic objects will not necessarily be appropriate (color constancy error). Three types of sensor models were used for the simulation. The error was reduced by a primary conversion that made overlaps and widths of the channels smaller. Thus two new metrics that evaluated the overlaps and the widths were defined and used to optimize the conversion to a color space suitable for white-balancing and it was shown that the color constancy errors were reduced. It was also shown that the color constancy error was small for the sensor model whose overlaps between channels were small and channel widths were narrow. The narrower widths and smaller overlaps of RGB channels gave less accurate colorimetric reproduction but less noisy images. In view of consumer digital cameras, the narrower widths and smaller overlaps of RGB channels is suitable because it can give less noisy images and consistent color reproduction with simple white balance processing.

Date Published: 24 January 2012
PDF: 6 pages
Proc. SPIE 8299, Digital Photography VIII, 82990N (24 January 2012); doi: 10.1117/12.907512

Published in SPIE Proceedings Vol. 8299:
Digital Photography VIII
Sebastiano Battiato; Brian G. Rodricks; Nitin Sampat; Francisco H. Imai; Feng Xiao, Editor(s)