Image data computing apparatus

An image data computing apparatus for computing three-dimensional image data on the basis of detection data obtained by transmitting an ultrasonic wave from transmission means toward points to be measured, which exist in a three-dimensional space, and detecting the ultrasonic wave reflected from the points to be measured by use of a two-dimensional sensor array including a plurality of sensors, said apparatus comprising:

• a line memory having a plurality of lines for storing the detection data obtained on the basis of output signals of said plurality of sensors respectively for a predetermined time period;
• storage means for storing as a table therein transfer time period data determined by relations between distances from the transmission means to the respective sensors through the respective points to be measured and transfer velocities of the ultrasonic wave in corresponding paths, and weighting factors for the detection data;
• and
• computation means for reading the detection data stored in said line memory in accordance with the transfer time period data stored in said storage means for the respective points to be measured, and for computing image data at the respective points to be measured by adding the read detection data after multiplying them by the weighting factors stored in said storage means for the respective points to be measured.