Despeckling Method for Medical Images Based on Wavelet and Trilateral Filter

In this chapter, an integrated despeckling approach for medical ultrasound images based on wavelet and trilateral filter is presented. Firstly, a dynamic additive model is developed to account for the medical ultrasound signal with speckle noise. Secondly, in accordance with the statistical property of the additive model, an adaptive wavelet shrinkage algorithm is applied to the noisy medical signal. Particularly, the algorithm is significant to the high-frequency component of the speckle noise in the wavelet domain. Thirdly, but most importantly, the low-frequency component of the speckle noise is suppressed by a trilateral filter. It simultaneously reduces the speckle and impulse noise in real set data. Finally, a lot of experiments are conducted on both synthetic images and real clinical ultrasound images for authenticity. Compared with other existing methods, experimental results show that the proposed algorithm demonstrates an excellent de-noising performance, offers great flexibility and substantially sharpens the desirable edge.