Apparatus for recording echo pulses

An apparatus for recording projection pictures of internal inhomogeneities in otherwise homogenous objects having a substantially plane or slightly curved surface on projection planes perpendicular to each other, the apparatus recording projection pictures by ultrasonic inspection according to the pulse-echo method, said apparatus comprising:

• ultrasonic inspection means having at least one ultrasonic angle probe for emitting and receiving ultrasonic sound pulses, said ultrasonic angle probe being freely movable in a two dimensional scanning movement over the surface of the object;
• position signal producing means for producing position signals containing information on the position of said ultrasonic angle probe and the direction of the projection of the ultrasonic sound pulses on the surface of the object;
• coordinate signal producing means responsive to echo pulses received from reflecting points in the object for producing, on the basis of the position signals and the transit time of the ultrasonic sound pulses, coordinate signals containing information on the spatial coordinates of the reflecting points in the object causing the echo pulses;
• memory means for storing echo pulse amplitudes, said memory means having a storage area for each of the perpendicular projection planes, said storage area having at least one storage position for each projection on the projection plane of reflecting points in the object;
• and
• recording means connected to said coordinate signal producing means for recording an echo pulse amplitude in each of said storage positions of said memory means, wherein said recording means records the echo pulse amplitude in at least one of said storage positions determined by the coordinate signals from said coordinate signal producing means if the echo pulse amplitude is higher than the last echo pulse amplitude recorded in said storage position.