Entropy-Based Local Histogram Equalization for Medical Ultrasound Image Enhancement

Local histogram equalization (LHE) has been widely used in image enhancement. In medical ultrasound image the region of interest usually surrounds by large area of dark background, which contains little information but consume lots of computational resource. Direct application of LHE will not only be time-consuming but also affect the global visibility due to background distortion. Based on the characteristics of medical ultrasound image, this paper proposes an entropy-based LHE algorithm by using local entropy value of a sub-block to decide whether LHE is applied on the center pixel of this sub-block. The method can accelerate the speed of processing and reduce the background distortion considerably.