Dimensional measurements on images from a video camera or cassette recorder using a BBC microcomputer.

We have developed a system that enables a BBC microcomputer to make dimensional measurements on images from a video camera or cassette recorder without a framestore. The RGB output of the computer is synchronized to the output of the camera or recorder and the two displayed simultaneously on the same monitor. Measurements can be made directly from the displayed image using points indicated by the computer graphics cursor via its keyboard. Distances can be measured with a precision of about 0.4%. The system is very versatile but is especially useful for measuring the freeze-frame output from a Philips standard videotape.