Contrast enhancement of medical ultrasonic images based on exact histogram specification

Objective: To employ an improved Exact Histogram Specification for contrast enhancement of medical ultrasonic images. Methods: An effective point of segmentation based on the characteristic of ultrasonic images was proposed, which divides the original image into background and foreground. The foreground was then enhanced with Local Exact Histogram Specification. Results: This method is capable of stretching local greylevel into a larger range. Thus the contrast of the original image can be enhanced; the over-enhancement of the black background of ultrasonic images can be reduced; and the detail information of the original image can be retained. Conclusion: The improved algorithm prevails in preserving original image's detail. Thus, the proposed method gains efficiency for medical ultrasonic images.