Digital image correlation (DIC) is a method for measuring the surface displacements and displacement gradients in materials under deformation. The method has also been applied to the calculation of image distortion for scanning probe microscopy (SPM). The traditional DIC method directly uses the intensity values of compared images but does not take out-of-plane nonlinearity error into account. However, in SPM measurements, the recorded z-direction value is a sum of the real surface height of the sample and any longitudinal deformation of the piezoelectric tube. In order to improve the calculation accuracy of the displacement fields, an improved DIC method is performed here. Two new parameters related to out-of-plane error are introduced in the mathematical modeling. The in-plane displacements between two compared images are then calculated pixel by pixel, with the z-direction error accounted for. This method is tested by applying it to two pairs of atomic force microscopy (AFM) images along the fast and slow scan directions.

This content is only available via PDF.
You do not currently have access to this content.