Dichromatic level-lines

Unlike edges, level lines are closed and less sensitive to external parameters. They provide a compact geometrical representation of images and they are, to some extent, robust to contrast changes. This paper proposes a novel and vectorial representation of color lines which does not require any color conversion. The topographic map is defined along each dominant color vector, from the body reflection, instead of the sole luminance direction in the RGB space. Experimental results show that this approach provides a better trade-off between compactness and quality. In addition, the lines extracted are quasi-invariant to illuminant changes.