Removing shadows from a single real-world color image

In this paper, we propose a new algorithm to remove shadow from a single color image. We first project log-log chromaticity coordinates onto an angle of illumination-invariant direction to obtain an illumination independent grayscale image. Then color information is added back by comparing intensities in the original and illumination-invariant grayscale images, and taking both global tonality and pixel-wise color into account. Finally, the result color image without shadow is recovered. The proposed method simplifies the color restoration procedure and therefore requires much less computation. Experimental results show that the new method can produce shadow-free images with same quality as those shown in previous work.