Computerized Enhancement of Ultrasonic Echograms

In the area of pulsed ultrasonics, there has been an effort to improve the resolution of compound scan (C‐scan) echograms. Most of the effort has been directed toward reduction of the transducer's beamwidth with such developments as composite transducers or focused transducers with variable focal distances. Problems of image saturation and artifact generation have received relatively little attention. This study reports on a method of generating without image saturation, a C‐scan echogram whose resolution is independent of the transducer's large beamwidth. Normal C‐scan information is recorded on analog magnetic tape and temporally expanded for construction of the target's positional likelihood distribution using a digital computer. Targets possessing vertical symmetry in the region scanned by the ultrasonic beam are used in a water bath to investigate the system resolution. After the likelihood distribution is constructed, it may be plotted, or numerical methods can be used to plot the processed echogram...