A time domain technique for implementing an adaptive wall filter improves imaging of low-velocity blood flow by removing signals associated with slowly moving tissue. Adaptive wall filtering is performed by estimating wall velocity and bandwidth, and then filtering the basebanded data with a complex...http://www.google.de/patents/US5445156?utm_source=gb-gplus-sharePatent US5445156 - Method for adaptively filtering doppler signals using a complex time domain filter
