Removing non-uniform illumination effects from deep-sea floor images

The deep-sea floor images are acquired under non-uniform illumination, the effects of which bring up many difficulties for image segmentation. The paper compares three methods of removing non-uniform illumination effects. The effectiveness and robustness are evaluated on three test images with high-, moderate- and low-density grains, respectively. The results show that local filtering algorithm does not remove the non-uniform illumination effects completely. The image subtracting algorithm will lose some of the dynamic range of the original data. The enhanced image stretching algorithm is the most effective one.