An Automatic Stopping Criterion for Contrast Enhancement Using Multi-scale Top-Hat Transformation

Image contrast enhancement is frequently referred to as one of the most important issues in image processing because it is a necessary pre-processing step in many computer vision and image processing algorithms. Contrast enhancement is normally required to increase the quality of low contrast images by expanding the dynamic range of input gray level. However, image contrast enhancement without disturbing other parameters of the image is one of the difficult tasks in image processing. To efficiently enhance images, algorithms based on multi-scale top-hat morphological transform (MSTH) have been proposed. However, scale selection to stop the algorithm is very subjective and empirical. In order to automatically select the iterations number required by MSTH algorithm, an automatic stopping criterion based on the contrast improvement ratio revisited is proposed in this paper.