| 摘要 |
PURPOSE:To reduce image strain and improves S/N by changing the cutoff frequency of the interpoltive function in dependence upon the magnitude of the power of resolution relative to the sampling period. CONSTITUTION:The ultrasonic waves are transmitted from an ultrasonic probe 1 into an object, the received signals are received at 3, added at 4, detected at 5 and taken in at a buffer memory 7A through an A/D converter. In the memory 7A, polar coordinate addresses of echo data are converted into rectiangular coordinate addresses and, in a register group 7B, echo data of picture element units and converted address data are taken from the memory 7A. In a subtractor 7C, differential data from sample lattice points are given as addresses to a ROM7D. The coefficient data showing optimum filter characterstics are selected. The echo data are multiplied in a multiplication unit 7E and the echo data are added by adders 7F, 7G. These added data are processed by a normalizing arithmetic unit 7H and written into a frame memory 71 so as to be displayed in the display system. |
