噪聲是影響醫(yī)學(xué)圖像質(zhì)量的最重要的因素之一。去除噪聲，增強(qiáng)圖像以提高圖像質(zhì)量是醫(yī)學(xué)圖像處理的重要課題。傳統(tǒng)的圖像增強(qiáng)方法在改善圖像視覺效果的同時還存在噪聲過增強(qiáng)問題，不適于醫(yī)學(xué)圖像增強(qiáng)。針對這種情況，文章提出了基于二維離散小渡變換的醫(yī)學(xué)圖像增強(qiáng)算法。在多尺度分析基礎(chǔ)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(jìn)行對比度增強(qiáng)處理，而對小波分解得到的不同方向上的小波系數(shù)進(jìn)行不同程度的去噪并增強(qiáng)。實驗結(jié)果表明，該方法在提高醫(yī)學(xué)圖像對比度改善圖像質(zhì)量的同時有效地解決了傳統(tǒng)算法中難以克服的噪聲放大問題。處理后的圖像更利于醫(yī)生進(jìn)行分析診斷和醫(yī)學(xué)影像的后續(xù)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．