关键词: 图像增强, 小波变换, 双树复小波变换, 方向选择性

Abstract:

In traditional image enhancement methods, such as histogram equalization, wavelet transform, etc, these methods achieve good performance, however, there still exist some drawbacks. The noise is amplified during the image enhancement processing. In this paper, an image enhancement method based on the 2D dualtree wavelet transform is proposed, aiming at the exsiting problem in traditional image enhancement methods.The 2D dualtree complex wavelet transform can describe the directional information of images better.The enhancement algorithm divides coefficients into three classes: strong, weak edge and noise point.The enhancement function will process the coefficients of each class respectively. The enhancement method adopted in this paper can suppress noise effectively. In this paper, the effect of parameters on the enhancement function is discussed taking PSNR as the evaluation standard, in order to optimize parameter selection.The experimental results show that the proposed method receives better performance.

Key words: image enhancement；wavelet transform；dualtree complex wavelet transform；directional selectivity