Color Calibration based on Mosaic Stitching of a Color Target as an Alternative to a Single-shot Approach

Abstract

Color targets come in different designs, sizes and surface finishes. A high quality color target such as the Next Generation Target (NGT) 1 , designed for the Library of Congress, has a glossy finish that makes it sensitive to the light-setup geometry. When the NGT color target is to be captured orthogonally, i.e. both the camera and the light share the same plane and lie on the normal of the target's surface, even with cross-polarization in place it is not possible to completely eliminate the high reflections caused by the camera/light geometry -unlike for less glossy color targets such as the X-Rite SG CC-not even if the camera/light setup were to be tilted at different angles. We are demonstrating in this paper that it is possible, however, to deploy a mosaic approach to capture the NGT color target at a tilted angle, masking out the reflections, and composing a rectified mosaic image out of only the clear parts of the target. The resultant ICC color correction profile for the mosaic image is proved to be viable to put in use and it satisfies all the necessary metrics for ISO level "A" when it comes to color calibration and color accuracy.