An Adaptive and Nonlinear Technique for Color Image Enhancement
Zhiguo Chang · Jisuanji fangzhen · 2008
In image processing and pattern recognition, extremely bright or dark regions may exist in images, which will result in not only the degradation of visual effect but also loss of some features of the images. This paper presents a novel color image enhancement algorithm based on an adaptive and nonlinear technique, which consists of five stages: converting color images to grayscale images; intensity transforming based on a specifically designed nonlinear transfer function; obtaining intensity information of neighborhood by a convolution process with a Gaussian kernel; enhancing contrast according to the information of neighborhood; restoring the color by a linear function. Finally, this algorithm is tested by SNoW-based face detector. The experiments show that the application of this image enhancement algorithm can effectively improve the hit rate of the face detection.