Because the conventional ultrasonic B-mode imaging device is scanning a measured plane by a pencil beam pulse, a multi-directional information can not be detected at the same time. This paper presents an instantaneous measurement technique which is able to image the echo-tomogram by transmitting an ultrasonic fan beam pulse and processing the echo signal backscattered from the object. We measured the cross section image of the copper wires, the vinyl seet and the sponge cube in the water vessel, and discussed on the method to alter for the better by the computer simulation. The results show that spot objects can be detected perfectly and that the probe with lengthening aperture and high frequency is effective to image a plane object and a volumic object better.
