# Effect of Non-Uniform Scale Degrees of Freedom

Enabling the non-uniform scale degrees of freedom in PatMax reduces the accuracy level to that of the PatQuick algorithm.

The x- and y-scale degrees of freedom allow you to specify variations from training to run-time objects that are called non-uniform scale variations, and provide alternative ways of specifying variations in aspect ratio from trained patterns to runtime objects. As with all generalized degrees of freedom, non-uniform scale variation can be specified using either nominal or zone parameters. Whenever a non-uniform scale zone is enabled, PatMax accuracy is limited to the lower accuracy of the PatQuick algorithm. Using non-uniform scale nominal values other than the default 1.0 results in no loss of accuracy.

If the aspect ratio of your objects truly varies, you may have no choice but to use a non-uniform scale zone and accept the lower accuracy. In some applications, however, aspect ratio does not vary from object to object, but is nevertheless different from the trained pattern. Do not use non-uniform scale zones to get PatMax to find the correct aspect ratio, because accuracy will be limited to the lower accuracy of the PatQuick algorithm. Instead use non-uniform scale nominal values, a calibrated coordinate space, or pattern coordinates to specify the fixed variation in aspect ratio from training to run-time.