Medical image colorization

Colorization is a term used to describe a computerized process for adding colour to black and white pictures, movies or TV programs. This process involves replacing a scalar value that represents pixels' intensity or luminance by a vector in a three dimensional colour space with luminance, saturation and hue or simply RGB. The colorization process is also used to convert the grey scale to colour on medical images. Colour increases the visual appeal of an image and it also makes a medical visualization more attractive. Changes in colour are more easily perceived then changes in shades of grey and therefore this procedure makes the interpretation and understanding of the image easier. Since the mapping between intensity and colour has no inherently "correct" solution, human interaction and/or external information usually plays a large role. In this paper we present a novel colorization method that takes advantage of the morphological distance transformation and image structures to automatically propagate the colour scribbled by the user within the grey scale image. The effectiveness of the algorithm allows the user to work interactively and obtain the desired results promptly after providing the colour. In the paper we show that the proposed method allows for high quality colorization results for still images without precise segmentation.