What is a video micrometer?

If a pattern (such as a crosshair) is needed to be placed over the image in a digital system, the combination of an image capture board and image analysis software can be used. If the same effect is needed for an analog system, a video micrometer is typically used. It is a device capable of laying controlled lines or patterns on an analog video output signal that is transmitted to a video printer or monitor. The only other way to place crosshairs, guidelines, or complex patterns on the image is to use a glass reticle placed in the video lens or microscope. Since most video lenses do not have this ability, using an electronic device is a viable alternative solution. For microscopes, an eyepiece that can accept a reticle is used and a relay lens is then used to connect the scope to the camera. Since different video micrometers have different functions, care must be taken to select the model that has the necessary capabilities.