Backward ray tracing for ultrasonic imaging

Focused ultrasonic beams frequently pass one or more media interfaces, strongly affecting the ultrasonic beamshape and focusing. A computer program, based on backward ray tracing was developed to compute the shape of a corrected focusing mirror. This shape is verified with another program; then the mirror is constructed by CNC (computerized numerical control) machining. The C/sup ++/ language gives a clear program structure with a toolkit of building blocks which can be applied to a wide range of problems. >