Color correction for mobile panorama imaging

This paper presents a simple and efficient color and luminance compensation approach for image sequences for constructing panoramic images on mobile devices. In this approach, constant compensation coefficients for adjacent images are computed from the corresponding pixels in the overlapping areas of the adjacent images in the linearized RGB color space. A global adjustment for all compensation coefficients is performed so that the correction for each image is as small as possible. This can smooth color transition between adjacent images in the image sequence globally and reduce cumulative errors in the color correction process. The compensation coefficients, together with the global adjustment factor, are applied to correct color and luminance of source images in the image sequence before they are stitched into a panoramic image. Our algorithm is not sensitive to the quality of spatial registration since it does not need exact pixel correspondences between the overlapped images. The computation of compensation coefficients for each adjacent image takes the gamma correction factor into account, producing better results. Running the method separately on the three channels matches the color balance that may not match due to auto-white-balancing algorithm. A global adjustment for the compensation coefficients minimizes color transitions and reduces cumulative errors. The approach is integrated into a sequential image stitching procedure and implemented in a mobile panorama system, good results have been obtained for both indoor and outdoor scenes.