噪聲是影響醫學圖像質量的最重要的因素之一。去除噪聲，增強圖像以提高圖像質量是醫學圖像處理的重要課題。傳統的圖像增強方法在改善圖像視覺效果的同時還存在噪聲過增強問題，不適于醫學圖像增強。針對這種情況，文章提出了基于二維離散小渡變換的醫學圖像增強算法。在多尺度分析基礎上，該算法對小渡分解得到的低頻子帶圖像采用兩步提升法進行對比度增強處理，而對小波分解得到的不同方向上的小波系數進行不同程度的去噪并增強。實驗結果表明，該方法在提高醫學圖像對比度改善圖像質量的同時有效地解決了傳統算法中難以克服的噪聲放大問題。處理后的圖像更利于醫生進行分析診斷和醫學影像的后續處理。
Noise is one of the most important factors，which affects the medical image quality Removing noise and enhancing image to improve the quality of image is the important item of medical image processing．Conventional image enhancement algorithms not only can improve the visual quality of image but also have shortcoming of noise over—enhancement．They are not suitable carrying on medical image processing．In order to solve this problem，this paper proposes a medical image enhancement based on two—dimensional discrete wavelet transform．On the basis of taking full advantage of multi scale wavelet analysis，the proposed algorithm improves the contrast of the approximations of the wavelet transform through two lifting steps，and shrinkages the coefficients of wavelet transform on the diferent degree and then enhances the coefficients．The results of experiment show that the proposed algorithm can raise the contrast of image and improve the quality of image，and resolve the problem of the noise magnified，which is hard to process in the conventional algorithms．Th e handled image is advantageous to the doctor to carry on analysis and follow—up processing of medical images．