| 摘要 |
PURPOSE:To detect structure properties of a local part of an object body quantitatively by calculating the linear analytic signal of an observation signal, calculating the instantaneous frequency of an image through the differential arithmetic of the phase of the linear analytic signal, and making it into an image. CONSTITUTION:The ultrasonic device of an observation signal detector 1 detects an ultrasonic image, which is digitized and stored in a two-dimensional memory 4. This observation signal is supplied to the 1st computing element 5 for primary Fourier transform and the result is stored in a two-dimensional memory 6 successively; and only its positive frequency component is read out and supplied to the 2nd computing element 7 for revese Fourier transform, and the result is stored in a two-dimensional memory 8. A divider 9 divides its imaginary part by the real part and the result is passed through a reverse tangent table 10 to obtain the instantaneous phase, which is stored in a two-dimensional memory 11. Two nearby picture elements in the time direction of the instantaneous phase are inputted to a difference calculator 12 successively to perform difference arithmetic and thus only the positive instantaneous frequency component of the ultrasonic image signal is obtained and stored in a two- dimensional memory 13. The value of the instantaneous frequency stored in the two- dimensional memory 13 is displayed on an output device 14. |
