JPS55145489A - Ultrasonic video device - Google Patents

Abstract

PURPOSE:To reduce the noise component and thus improve the S/N ratio, by collecting continuously the images of the same target through plural number of frames and then integrating these images in terms of the time. CONSTITUTION:The picture data matrix supplied through terminal 21 at time point n is referred to as Xn, and the picture data matrix stored in picture memory 26 is Yn respectively. Thus subtractor 22 calculates Xn-Yn, and digit shifter 23 shifts Xn-Yn by k-bit digit to obtain (Xn-Yn)/2<k>. Adder 25 adds Yn to (Xn-Yn)/2<k> to calculate new picture image Yn+1. Here Xi is attenuated by time constant 2<k> and based on the process of n. Now picture row Xi reproduced sequentially with standstill of the target is added to target image S which is reproducible, and the weighted average of past noise picture row Ni is added to image S for Xi=S+Ni on which random noise picture row Ni piled. And the latter can be lowered down for its value as k becomes larger, thus the S/N ratio can be increased.