ULTRASONOGRAPH WITH ZOOM DISPLAY FUNCTION

PROBLEM TO BE SOLVED: To quickly cope with a change in a display form of a zoom display by obtaining a zoom image from inputted ultrasonic data on polar coordinates by using a zoom transformation table by shifting a standard transformation table on the basis of a zoom rate. SOLUTION: A standard conversion table 63 for performing rectangular coordinate-polar coordinate transformation from a transformation tale storage part 61 existing in an input storage part 51 of an external memory 50 is read in an internal storage part 65 of a DSP 60. Ultrasonic input data is read in the internal storage part 65 of the DSP 60 from an image storage part 5 existing in the input storage part 51 of the external memory 50. Polar coordinates corresponding to rectangular coordinates are obtained by the standard transformation table 63 to perform four-point interpolation on an image value corresponding to polar coordinates by a four-point interpolative operation part 66 by using the ultrasonic input data. A zoom transformation table 73 having a zoom rate, for example, two times is determined by performing an interpolative operation on a interpolative point, and an image value of the rectangular coordinates is determined by performing four-point interpolation from a determined polar coordinate value.