FLIR Systems, Inc.
SYSTEMS AND METHODS FOR REDUCING LOW-FREQUENCY NON-UNIFORMITY IN IMAGES

Abstract:

Various techniques are disclosed for separating and removing low-frequency shadow or shading (also referred to herein as "non-uniformity") from images that have been corrupted by the non-uniformity. A non-uniformity estimate that approximates the non-uniformity effect on the corrupted image may be generated by iteratively adding new blotches of non-uniformity data represented by two-dimensional (2D) functions, such as 2D Gaussian functions, to the non-uniformity estimate and applying filters to smoothen the 2D functions. In each iteration of the non-uniformity estimate generation process, a new non-uniformity update candidate that minimizes a cost function is identified. The corrupted image is processed based on the non-uniformity estimate to generate a corrected image.