Contrast enhancement method of medical ultrasonic images based on preserving brightness

Objective: To explore contrast enhancement method of medical ultrasonic images based on preserving brightness. Methods: Based on improving of traditional histogram equalization, the proposed method adopts the minimum mean brightness error bi-histogram equalization and an effective intersected point. Results: We propose a method of local histogram equalization-brightness preserving tri-bidirectional histogram equalization. Conclusion: Simulation results showed that comparing to other methods of histogram enhancement, this method prevails in its finely restrain fulsome enhancement of black background, preserving original image's detail and brightness, and enhancing the contrast.