| 摘要 |
PURPOSE:To clear the contrast of an image, by mounting a means for displaying only impedance present in the certain range of the two-dimensional distribution of the acoustic impedance of a specimen. CONSTITUTION:Digital amount (e.g., 8 bit) output showing relative impedance is converted to an analogue signal by a D/A converter 610 and this analogue signal is obtained as a CRT luminance signal through an analogue SW630. This analogue signal is inputted to a window comparator 620 and, at the time of amplitude between the lower limit level X1 and upper limit level X2 of the relative impedance indicated by an operator, the analogue SW is turned ON by the output of the comparator 620. By this method, the signal within a range of X=X1-X2 id displayed on CRT as it is but, because the analogue SW is OFF, the other signal is not displayed to achieve the function of the selection of an impedance level. As a result, the contrast of an image can be cleared. |
