Illumination Intensity, Object Geometry and Highlights Invariance in Multispectral Imaging

It is well-known that image pixel values of an object could vary if the lighting conditions change. Some common factors that produce changes in the pixels values are due to the viewing and the illumination direction, the surface orientation and the type of surface. For the last years, different works have addressed that problem, proposing invariant representations to the previous factors for colour images, mainly to shadows and highlights. However, there is a lack of studies about invariant representations for multispectral images, mainly in the case of invariants to highlights. In this paper, a new invariant representation to illumination intensity, object geometry and highlights for multispectral images is presented. The dichromatic reflection model is used as physical model of the colour formation process. Experiments with real images are also presented to show the performance of our approach.