Ultrasound imaging is a widely used method for medical applications. It is noninvasive, real-time and relatively inexpensive. However, compared to o ther medical imaging methods, it suffers from low signal to noise ratio, the presence of speck le, signal dropouts, and a low contrast. The speckle appears as a multiplicative, locally correlate d noise caused by destructive interference of signals reflected from scatterers within o ne resolution cell. This phenomenon degrades the resolution of images and makes difficult the d etection of their features. Hence, the development of effective noise reduction filte rs for echographic.