| pubmed-article:803986 | pubmed:abstractText | The use of an ultrasonic delay line and mechanical arm as a means of checking the registration of contact B-scanners is described. The principle of operation is applicable to any make of equipment. The amount of misregistration can be assessed, and discontinuities or departures from the normal can be demonstrated in the transducer position sensing system. As an added benefit it is a rapid means of checking both picture size and the accuracy of electronic markers. | lld:pubmed |
