# Optimizing Tile Size

In general, increasing the number of tiles visible in the calibration image (by reducing the size of the tiles on the calibration plate), improves the accuracy of the calibration, although the improvements are smaller the greater the number of tiles that are present. In most cases, since the only negative effect of increasing the number of tiles is that it takes longer to compute the calibration, you should size your tiles so that there are several hundred tiles visible in the image.

Also, since accuracy improves when the vertex points are spread evenly across the entire image, make sure that the calibration image is completely filled with tiles, as shown in the following figure:

Note: If you are only interested in measuring objects or positions in part of the input image, you should only include tiles that cover that part of the image. Attempting to correct distortion in parts of the image that are not of interest to your application can reduce the accuracy of the calibration in the parts of the image that you are interested in, and can slow your application.