An efficient algorithm to remove low frequency Doppler signals in digital Doppler systems

In color flow imaging, a high flow map rate in combination with a reasonable width of the map and good velocity resolution is essential to properly appreciate the time-dependent phenomena. The velocity resolution depends on the length of the signal segment considered in combination with the settling time of the high pass filter used to eliminate transients and low frequency artifacts. The latter can be reduced by appropriate processing. This paper presents an algorithm to suppress low frequency Doppler signals effectively and efficiently, while all the data points within the segment considered contribute equally to the average Doppler frequency computed. The algorithm is applied to computer generated Doppler signals to evaluate their time and frequency behavior. It is concluded that the proposed scheme functions adequately under various signal conditions.