Ultrasonic tomography device

For producing a tomographic ultrasonic sectional image a plurality of B scans have to be superposed which were obtained from different angular directions. These different aspect angles are implemented by means of four linear ultrasonic transducer arrays (2i) which are arranged around an object under examination (6) in the shape of a square and are driven one after the other in terms of time. Before the superposition can take place the B scans which are present in each case in relative coordinates (xi, yi) have to be recalculated (converted) into the stationary coordinate system (x, y) of a monitor (10). According to the invention, for this coordinate transformation an analog calculation circuit (20) is provided with two analog multiplexers (22 and 28) as well as two operational amplifiers (42 and 44) by means of which the relative coordinates (xi, yi) are optionally reversed and inverted. The picture is shown on a monitor (10) which has separate inputs for brightness (z) and the horizontal (line) deflection (x) and vertical deflection (y). As a result, the time needed for calculating the coordinate transformation becomes virtually negligible and the real-time graphical presentation of tomographic ultrasonic sectional images becomes possible.