Color flow imaging system utilizing a time domain adaptive wall filter

In a vibratory energy imaging system which includes a receiver that demodulates an echo signal received from a vibratory energy transducer to produce a baseband echo signal, a color flow processor which comprises:

• a first autocorrelation estimator coupled to receive the baseband echo signal and to produce an output signal .phi.(T) indicative of the mean frequency of said baseband echo signal;
• a complex mixer coupled to receive the output signal .phi.(T) and the baseband echo signal and to shift the frequency of the baseband echo signal by an amount indicated by the output signal .phi.(T);
• a high pass filter coupled to receive the frequency shifted baseband echo signal from said complex mixer and to filter out signal components therein having a frequency near zero;
• a second autocorrelation estimator coupled to receive the filtered, frequency shifted baseband echo signal from the high pass filter and to produce an output signal .phi."(T) which is indicative of the mean frequency thereof;
• and
• chrominance control means coupled to receive the output signal .phi."(T) from said second autocorrelation estimator and to control color of a display in response to said second autocorrelation estimator output signal.