ANALYSIS OF B-SCAN SPECKLE REDUCTION BY RESOLUTION LIMITED FILTERING

Much of the signal energy due to speckle in ultrasound images is shown to be of higher spatial frequency than the intrinsic pulse shape limited resolution in B-scan ultrasound images. A significant increase in signal to noise ratio can therefore be obtained by resolution limited spatial filtering which selectively removes energy of higher spatial frequency than the pulse envelope reso-lution limit. The concept is illustrated by resolution limited filtering ECG gated B-scan echocardio-graphic images. Signal to noise improvement is illustrated by comparing time-motion displays gen-erated from both processed and unprocessed images. Key words: B-scan, filtering; resolution; speckle; ultrasound I