Correction of axial and lateral chromatic aberration with false color filtering

In this paper, we propose a chromatic aberration (CA) correction algorithm based on a false color filtering technique. In general, CA produces color distortions called color fringes near the contrasting edges of captured images, and these distortions cause false color artifacts. In the proposed method, a false color filtering technique is used to filter out the false color components from the chroma-signals of the input image. The filtering process is performed with the adaptive weights obtained from both the gradient and color differences, and the weights are designed to reduce the various types of color fringes regardless of the colors of the artifacts. Moreover, as preprocessors of the filtering process, a transient improvement (TI) technique is applied to enhance the slow transitions of the red and blue channels that are blurred by the CA. The TI process improves the filtering performance by narrowing the false color regions before the filtering process when severe color fringes (typically purple fringes) occur widely. Last, the CA-corrected chroma-signal is combined with the TI chroma-signal to avoid incorrect color adjustment. The experimental results show that the proposed method substantially reduces the CA artifacts and provides natural-looking replacement colors, while it avoids incorrect color adjustment.