Fast edge-preserving noise reduction for ultrasound images

Edge-preserving noise reduction is an essential operation for computer-aided ultrasound image processing and understanding. This paper describes a novel filter which is a two-dimensional extension of the one-dimensional Savitzky-Golay filter. The new filter, referred to as the two-dimensional weighted Savitzky-Golay filter, is based on the least squares polynomial surface fitting to image intensities. The performance of the proposed filter has been compared with that of the commonly used median filter in reducing speckle noise in ultrasound images. Experimental results indicate that the new filter can achieve, at least, the same level of noise reduction and edge preservation as that of the median filter, but with far less computation rims. Since its complexity scales linearly with the problem size, the new filter is suitable for filtering problems with large windows. In addition, it also shows to be less sensitive to the size of the filtering window compared to the median filter.