Directional Savitzky-Golay filters for real-time speckle reduction and coherence enhancement of medical ultrasound images

This paper describes a new filter developed for real-time speckle reduction and coherence enhancement of medical ultrasound images. The new filter, referred to as the directional Savitzky-Golay (DSG) filter, is a two-dimensional weighted Savitzky-Golay filter enhanced with a mechanism for adjusting its smoothing direction to conform to the anisotropic properties of each local region in the image. The performance of the new filter is compared with that of the adaptive speckle reduction filter and the adaptive weighted median filter in reducing speckle noise and enhancing coherence of an ultrasound thyroid image.