PURPOSE: To obtain a better Doppler color image by enabling highly accurate computation of a speed without increasing the scale of a signal processing.
CONSTITUTION: A received signal of a reflected ultrasonic wave obtained from an ultrasonic probe 1 is detected in orthogonal phase with mixers 4 and 5. Cutoff frequency of highpass filters 15 and 16 is heightened by a control signal A which is evaluated that more clutter components exist with an amplitude evaluating section 14 from the intensity of I and Q signals obtained to remove a low frequency clutter component. Outputs from the highpass filters 15 and 16 are converted to speed information with a speed computing section 17 and written into a scanconverter 20 to be displayed at a display section 21 as Doppler color image.
HAGIWARA TAKASHI
NISHIGAKI MORIO
