A novel shadow removal algorithm using Niblack segmentation in satellite images

Shadow is formed by the interaction of light with object. Effect of shadow is very crucial in the case of satellite image processing. Roads, buildings, trees etc are detected for various applications. But the interference of shadow makes mismatching of these objects. Several algorithms are being developed to detect and reconstruct the shadow region. This paper presents a Shadow detection technique based on Niblack segmentation. Niblack segmentation gives better shadow regions compared to Otsu's thresholding method and Sauvola based thresholding. Reconstruction of the shadow region is done by the Bayesian classifier. This classifier generate a training vector and reconstruct non shadow region from shadow region. Posterior probability is determined to reconstruct the non shadow image intensity level. This algorithm is successfully tested with VHSR images.