Calibration Accuracy

The accuracy of the calibration depends on a number of factors, including the following:

The part of object being inspected; smooth edges are optimal, while rough, burred edges will reduce accuracy.
The quality of the printed/manufactured calibration grid; a calibration grid that is printed on a standard ink jet or laser printer will limit accuracy.
The quality of the lens; high quality lenses with telecentric properties will provide the best results and require the least amount of correction.
How the In-Sight vision system is mounted; if the vision system is mounted in an area that vibrates, the vision system may move over time.
The quality of the image; if the image has too much Gain, the pixels will jitter, and if the image is over-exposed, accuracy will be reduced. For more information, see AcquireImage.
The accuracy of the Vision Tools. The Edge tools are accurate to .25 (1/4) pixels, while the PatMax tools are accurate to .025 (1/40) pixels.

Accuracy is severely degraded when these problems are allowed to aggregate; these problems tend to be additive and very rarely do they cancel each other out. Accuracy to .10 (1/10) pixels is possible when the part being inspected is flat and has extremely well defined edges. The only way to determine the accuracy of your system is to test it.