Check my chart: a robust color chart tracker for colorimetric camera calibration

We present an algorithm to detect and track color calibration charts in images robustly. A model of the calibration chart describes the geometry of the chart regions by polygons along with the related reference colors. A homography maps the model into the image and an optimizer adapts the mapping parameters to align the model regions to the chart in the image. We propose a cost function that evaluates the quality of model alignment based on color statistics and an efficient method to extract color statistics in polygonal image regions using the integral image. The algorithm measures the colors of the chart in the image and determines correction parameters. Without loss of generality, we describe the method using the X-Rite ColorChecker Classic as a typical chart. Experiments show the robustness to noise and blur and the real-time capability of the system.