Real-Time Advanced Contrast Enhancement Algorithm

The image quality enhancement based on digital signal processing (DSP) has been addressed as one of the crucial issues in digital display technology and market. Since real-time digital imaging should be controlled in limited speed and bits, colored motion pictures with digital display generally generate many problems such as limited operating speed of algorithm and gamut range of expressed color compared to analog cathode ray tube (CRT) display. Especially, the contrast enhancement with limited values sometimes may result in overpassing contrast limit. The changes of hue and saturation cause a damage of color nature of original image. Moreover, the abruptly changed gain during contrast enhancement causes the flickering problem as time passes. This paper introduces the image contrast enhancement algorithm named Advanced Contrast Enhancement (ACE) with adaptive and recursive method which operates at 135MHz, SXGA, keeps the color tone of original image, and prevents gain from an abrupt change. The chip with ACE algorithm will be useful not only for general imaging but also for special treatment such as medical imaging to detect problems in human body pictures such as X-ray picture, ultrasound, and CT in real-time.