基于小波变换的血管内超声图像血流斑点噪声抑制研究

血管内超声成像已经越来越广泛地应用到冠心病的诊断和介入治疗中.为了提高图像分辨率必须增加超声频率,使得血流斑点噪声也显著增强,降低了管腔和管壁的对比度,增加了识别管壁与周围组织的难度,给病情的诊断和治疗带来了不便.本研究结合小波变换域软阈值滤波法和半软阈值滤波法,并设计了一种局部阈值来实现血流斑点噪声抑制.实验结果表明该方法在抑制斑点噪声的同时保留了图像的边缘,增强了管腔和管壁的哪对比度,有助于识别管壁和周围组织.

A Blood Speckle Reduction Method Based on Wavelet Transform of Intravascular Ultrasound

Intravascular ultrasound (IVUS) has been applied into the diagnosis of coronary heart disease and the relevant intervention therapy more and more widely. However, the frequency of ultrasound must be increased in order to improve the resolution of images, which makes the blood speckle noise increase significantly,decreases the contrast of lumen and arterial wall structure, increases the difficulty to discriminate arterial wall from structures, and makes it inconvenient to diagnose and treat illness. In this paper a wavelet shrinkage method based on local threshold is introduced to reduce blood speckle noise. Results show that the method can remove the speckle noise, keep the edges of image, increase the contrast, and thus is helpful to the identification of the arterial wall and the tissues around.