Colour Adjustment and Specular Removal for Non-uniform Shape from Shading

Surface colour changes and specular reflections are two major problems in 3D modelling using shape-from-shading (SFS). This paper proposes to pre-process the input image for a typical SFS algorithm, so that the resultant image has no colour changes and specular reflection. First, a chromaticity-based specular reflection removal algorithm is applied to achieve a pure diffuse (Lambertian) reflected image. Then, a novel chromaticity-based colour adjustment approach is proposed to generate an image without surface colour changes. The standard SFS algorithms can then be applied successfully onto the processed images to produce plausible 3D models. In experiments, the proposed approach was tested on standard SFS datasets with complex surface colours. The experimental results show it´s promising to facilitate SFS algorithms to handle SFS problems with more complex surface properties and illumination conditions.