Shinichi Amemiya

Method of displaying stream lines of an inhomogeneous flowing medium and a device therefor

A method and device to display in real time a stream line of an inhomogeneous flowing medium such as blood flow in a heart, is disclosed. The object is scanned several times by ultrasonic beam pulses. Echoes appearing within a predetermined time interval at each point of the object are combined to produce an image of speckles formed by the flow. The process is repeated several times, to obtain the motion of the speckles. Differences between the images of spatially correlated speckles obtained within the time interval, produce the segments of the stream lines. Differences between successive frames or successive lines can be used to produce the speckle and several methods of scanning are disclosed to produce the differences between the images to produce the stream lines.

Ultrasonic continuous wave blood flowmeter using Doppler effect analysis

An ultrasonic continuous wave blood flowmeter using Doppler effect analysis includes a filter having a cut-off frequency determined in part by a manually selected zero shift value. A tranducing device, in the flowmeter includes a transmission element and a reception element, the transmission element transducing an electric transmission signal into an ultrasonic signal to irradiate a living body and the reception element transducing a reflected ultrasonic signal into an electric reception signal. A detecting circuit is operatively connected to the transducing device for orthogonally detecting the electric reception signal and outputting a Doppler detection signal. A filter circuit is operatively connected to the detecting circuit for cutting high frequency components of the Doppler detection signal based on the cut-off frequency and outputting an analog signal. A converting circuit is operatively connected to the filter circuit for converting the analog signal of the filter circuit to a digital signal based on a Doppler sampling frequency having a continuous wave. A transforming circuit is operatively connected to the converting circuit for analyzing the digital signal and obtaining a Doppler frequency spectrum based on a Fourier transform method. A control circuit is operatively connected to the filter circuit for controlling the cut-off frequency based on the Doppler sampling frequency and the zero shift value.