Integrated digital image correlation for the evaluation and correction of optical distortions

Abstract

Optical aberrations are one of the biases affecting images. Their correction can be performed as a transformation of the image. In this paper, it is proposed to use digital image correlation to calculate the distortion fields. A correlation calculation is performed between a known numerical pattern and a picture of the same pattern printed or etched on a plate. This new procedure is applied to determine the distortion fields of a camera lens. First, a parametric description of the distortion field is used to reduce the degrees of freedom required to describe optical distortions. Second, a non-parametric model based upon splines is used. The distortion fields found by both methods are compared. A resolution analysis is performed for two different procedures (removing the lens between pictures or not). The standard displacement resolution is found to be of the order of 10-2 pixel in the first case, and 2.5×10−3 pixel in the second case.