Vision calibration targets are precision test samples or patterns that are printed or etched on a substrate of glass or other material for dimensional calibration and depth-of-field determinations of machine vision systems, cameras, or microscopes. Vision calibration targets are used to measure various machine vision system field parameters, such as magnification, distortion, and anamorphism, which is the distortion of an image in a specific way so that it is only visible when viewed under specific circumstances.
Vision calibration targets include different designs to test different machines. Machine vision calibration is done with round dot pattern targets and chrome-on-glass reticules, or grids. These grids are used to inspect and calibrate laser image setting equipment, clinical instruments, and semiconductor processing systems. Round dot pattern vision calibration targets are less sensitive to the limitations of resolution and provide effective measurements. Reticles are high contrast targets that are either back- or front-lit, which makes them useful in all kinds of microscopy applications. Calibrating visions systems is vital to maintaining the quality of images and may reveal problems with different components of the machine vision system, such as resolution or the depth field.
Vision calibration targets are developed for electro-optical targeting systems in weaponry or cameras used in combat or surveillance applications. Vision calibration targets used in these applications may include using cross-hair patterns to accurately aim or focus the electro-optical device. Cross hairs are two strands of wire at right angles to each other in the eyepiece of the instrument used for sighting the target.
Vision calibration targets are used in automated or robotic equipment, medical diagnostic equipment, and manufacturing monitoring equipment. A vision calibration target can be used in two-dimensional and three-dimensional vision systems. Calibration images may also be part of a computer program used to calibrate cameras. Vision calibration targets for digital cameras including panels for white balancing, exposure, and light meter calibration.