Measuring accurately-does your calibration technique get the job done?

When measuring it is important to understand all of the factors which affect accuracy. Using a vision system to measure is no different. Proper selection of the system components is not enough. It is true that most vision systems have the internal capability to extract measurements using sub-pixel techniques, but it is important not to think your system is actually that accurate if you fail to compensate for system induced distortions. The author considers simple calibration, X and Y scaling, perspective and distortion, robust calibration, multiple camera set-ups, multiple camera calibration, and three-dimensional calibration