Summary
International Technical Conference on Circuits/Systems, Computers and Communications
2008
Session Number:P1
Session:
Number:P1-65
Auto White Balance Using Chromatic Coordinates of Detected Human Faces
Jung-Wook Lee, Kyu-Ik Sohng,
pp.-
Publication Date:2008/7/7
Online ISSN:2188-5079
Summary:
This paper proposes auto white balance algorithm for the picture that is taken for people. General white balance algorithms bring neutral region into focus. But, other objects can be basis if its spectral reflectance is known. In this paper the basis for white balance is human face. For experiment, first, transper characteristic of image sensor is analyzed and camera output RGB on average face chromaticity under standard illumination is caculated. Second, Output rate for the image is adjusted to make RGB rate for the face photo area taken under unknown ilumination RGB rate that is already caculated. Input tristimulus XYZ can be calculated from camera outpu RGB by camera transfer matrix. And input tristimulus XYZ is transformed to standard color space (sRGB) using sRGB transfer matrix. For display, RGB data is encoded as eight-bit data after gamma correction. Algorithm is applied to average face color that is light skin color of Macbeth color chart and average color of various face colors that are actually measured.