| 摘要 |
PROBLEM TO BE SOLVED: To reduce the deterioration of spatial resolution in a distance direction when reducing a speckle according to frequency compound method in an ultrasonograph. SOLUTION: A plurality of narrow-band signal components are extracted from received signals by mutually different narrow-band pass filters, and wide- band signal components are extracted from received signals by wide-band pass filters. The respective signal components are weightedly added. Besides a plurality of the narrow bands, the wide band including them is set so that the ultrasonograph can cope with the deterioration of the time dissolution in the distance direction. It is preferable that the frequency characteristic of the band pass filter is sequentially variable according to the depth of echo. |
