Quaternion-Based Albedo Recovery for Shape Reconstruction

A new quaternion based method is presented which recovers albedo for shape reconstruction from three color images for three directions of white light source. In the conventional approaches, red, green and blue components are considered separately so there is a loss of information. The albedo maps recovered are not accurate enough to recover shape. Property of quaternion is that a color can then be processed as a unit, rather than as three separate channels. Using this three color band components from three input images are combined to form a quaternion. First, the albedo maps are derived from product matrix formed by the input images and illumination matrix. By using the recovered albedo, surface normal of the image is obtained. Comparison of recovered albedo with the conventional Color photometric stereo (CPS) is done by an accuracy parameter to analyze the performance of the proposed work. Key-Words: Color photometric stereo, Quaternion, Optical polarization filters, Illumination matrix, Jacobi transformation, Hermitian matrix.