# Expected and Maximum Deformation Rate

Different instances of a trained pattern can exhibit different amounts of deformation. The PatFlex algorithm expresses the degree of pattern deformation as the pattern's deformation rate. A pattern's deformation rate is a value in the range 0.0 through 1.0. A value of 0.0 indicates no deformation, while a value of 1.0 indicates a highly deformed pattern.

The deformation rate represents the percentage of variance between the undeformed location of a control point in the run-time image and the found location of the control point. The following figure provides a visual guide for estimating pattern deformation.

You specify two deformation rate values: the expected deformation that can be accommodated (specified at training time) and the maximum deformation rate for a particular input image (specified at run time).