Auxiliary control unit for video based instrumentation systems - allows geometrical coordinates to be selected and displayed

摘要

The auxiliary unit is for use with closed-circuit television instrumentation systems. It consists of an electronic switch between a camera and a monitor by which the black level or white level of certain scanning lines can be controlled. A line counter with pre-selector input via an analogue-digital converter is coupled to an OR-gate. A further counter with output to the gate, has an X coordinate input. With the two counters, the X and Y coordinates (line and row) can be displayed as black or white lines on the monitor. A sample-and-hold circuit registers the instantaneous luminance signal from the camera when the output signals from the counters are present at the same time. Measurement of distance between two items of differing contrast is possible via a comparator and position counter.