| 摘要 |
PURPOSE:To correct the delay quantity with high accuracy even in the case a strong reflecting body is present in a living body by providing a means for eliminating the low frequency component of a measured propagation time difference distribution. CONSTITUTION:When a propagation time counting part 14 receives a receiving signal obtained by each vibrator of a probe 10 through a reception delay part 12, its propagation time is counted and the difference of a propagation medium in a living body is derived as a propagation time difference distribution curve. Subsequently, a low frequency eliminating part 15 derives a low frequency component by using a moving average method from the distribution curve derived by the measuring part 14, eliminates this low frequency component, and also, outputs a delay time correcting signal from which the low frequency component included in the distribution curve is eliminated, to a delay control part 16. Then, the delay control part 16 controls a delay time in a transmission delay part 13 and the reception delay part 12, based on the delay time correcting signal and a delay time signal from a CPU 17. In such a manner, even in the case a strong reflecting body, etc., are present in the living body, the focus of an ultrasonic beam can be stopped and a distinct ultrasonic image having no distortion can be obtained. |
