Color flow imaging system utilizing a time domain adaptive wall filter
First Claim
1. 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 φ
(T) indicative of the mean frequency of said baseband echo signal;
a complex mixer coupled to receive the output signal φ
(T) and the baseband echo signal and to shift the frequency of the baseband echo signal by an amount indicated by the output signal φ
(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 φ
"(T) which is indicative of the mean frequency thereof; and
chrominance control means coupled to receive the output signal φ
"(T) from said second autocorrelation estimator and to control color of a display in response to said second autocorrelation estimator output signal.
1 Assignment
0 Petitions
Accused Products
Abstract
An ultrasonic imaging system for displaying color flow images includes a receiver which demodulates ultrasonic echo signals received by a transducer array and dynamically focuses the baseband echo signals. A color flow processor includes a time domain adaptive wall filter which automatically adjusts to changes in frequency and bandwidth of the wall signal components in the focused baseband echo signals. The mean frequency of the resulting filtered baseband echo signals is used to indicate velocity of flowing reflectors and to control color in the displayed image.
76 Citations
17 Claims
-
1. 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 φ
(T) indicative of the mean frequency of said baseband echo signal;a complex mixer coupled to receive the output signal φ
(T) and the baseband echo signal and to shift the frequency of the baseband echo signal by an amount indicated by the output signal φ
(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 φ
"(T) which is indicative of the mean frequency thereof; andchrominance control means coupled to receive the output signal φ
"(T) from said second autocorrelation estimator and to control color of a display in response to said second autocorrelation estimator output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. 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 method of operating a color flow processor that controls a display system, said method comprising the steps of:
-
producing a signal φ
(T) indicative of the mean frequency of said baseband echo signal;shifting the frequency of the baseband echo signal by an amount indicated by the signal φ
(T);filtering signal components having a frequency near zero out of the frequency shifted baseband echo signal; and controlling color of a display in accordance with the mean frequency of the filtered, frequency shifted echo signal. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
-
Specification