The Invariance Properties of Chromatic Characteristics

[[abstract]]An approach to analyzing the degrees of invariance of chromatic characteristics is proposed in this paper. In many vision applications, it is desirable that the chromatic characteristics of objects in images taken under different lighting conditions could remain constant. However, the invariance properties of chromatic characteristics are subject to the lighting conditions. In order to be able to apply to dynamic scenes, we consider three fundamental lighting sources: diffuse, ambient, and directed lightings. Any illumination condition can be approximated as a combination of the three lighting sources. The proposed degree of chromatic invariance is defined based on the chromatic characteristic behaviors under different illumination conditions. A lot of image samples under different illumination conditions are utilized, and from experimental results, we conclude that chromatic characteristics {H, C, Cλ} are most stable and suitable for the vision applications.