1. A method of processing ultrasound image data to reduce acoustic speckle noise and enhance selected portions of the image, the image being formed from a plurality of pixels arranged in a spatial array and said data representing an intensity level in each pixel, the method comprising weighting the data representative of preselected ones of less than all of the pixels of an asymmetric portion of said spatial array with predetermined coefficient values, said preselected pixels and said coefficient values being selected to enhance the leading edges of spots in the image which have a size greater than a predetermined size corresponding to an average size of acoustic speckle and which have a predetermined location in the asymmetric portion; combining the weighted data to produce a transformed intensity value; repeating said weighting and said combining for a plurality of different asymmetric portions of the spatial array; forming another array of pixels by using each transformed intensity value as a value of a pixel of said other array which corresponds to a central pixel of the corresponding asymmetric portion; and displaying said other array as an image.