Any machine vision lens (either telecentric or not) shows some amount of distortion. In addition to barrel or pincushion distortion, changes in the view angle or misaligned components will affect the image symmetry and generate the so called thin prism or keystone effect. Imaging and metrology applications often require to minimize distortion, which can be software-corrected by analyzing the image of a precision pattern whose geometrical features are well known. For this reason Opto Engineering offers chrome-on-glass patterns optimized for software calibration, featuring extremely high geometrical accuracy thanks to photolithography techniques. The range of available chessboard patterns is compatible with most Opto Engineering telecentric lenses.