Mixing Apple microcomputer graphics for ultrasound scan measurement.

A modern microcomputer with high-resolution graphics can provide an inexpensive method for measurement on video images from a real-time ultrasound scanner. The problem which has to be overcome to allow the computer graphics to be superimposed on the ultrasound video image and permit subsequent analysis is that of synchronization. The video signals must be synchronized before they can be mixed, but neither microcomputers nor ultrasound scanners provide facilities for external synchronization of their video output. A mixer has been designed which uses a buffer memory and allows the graphics of an Apple II microcomputer to be synchronized and mixed with an external video image; we used a Hitachi EUB22 real-time ultrasound scanner. The resulting combination is a versatile instrument which permits a wide range of measurements on ultrasonic images.