Isoline Based Image Colorization

Colorization is a process of adding colors to black and white images and videos. Each scalar pixel value is replaced by three values which describe, depending on color mode, e.g. The luminance and the chrominance or red-green-blue components. By introducing colors, the resulting image benefit greatly. Not only that it is more attractive for a viewer, but also the perception of hardly noticeable features increases, which is crucial e.g. In medical image analysis. In our paper we present a novel algorithm for grayscale image colorization. The idea is based on the concept of isolines on geographical maps. For each color indicated by a user with scribbles, we create distance maps which present the measure of distance between a pixel and the colored region. The resulting color is calculated as a weighted average of all colors indicated by the user in a form of scribbles. The method is computationally efficient and can be adjusted by several parameters to obtain optimal colorization results. We present several multimedia and biomedical images, colorized using our approach.