With the current trend of digital convergence in mobile phones, mobile manufacturers are researching how to develop a mobile beam projector to cope with the limitations of a small screen size and to offer a better feeling of movement while watching movies or satellite broadcasting. However, mobile beam projectors may project an image on arbitrary surfaces, such as colored walls and papers, not only on a white screen as is mainly used in an office environment. Thus, a color correction method for the projected image is proposed to achieve good image quality irrespective of the surface color. Initially, luminance values of the original image in the YCbCr color space are changed to prevent unnatural luminance reproduction of the projected image, depending on the contrast and luminance of the surface image captured with a mobile camera. Next, the chromaticity values for the captured surface and white screen images are calculated using a ratio of the sum of three RGB values compared to one another. Then, their chromaticity ratios are multiplied by the converted image through an inverse YCbCr matrix to reduce the influence of modulating the color tone of the projected image due to spatially different reflectances on the surface. By projecting the compensation image on a texture pattern or single color surface, the image quality of the projected image can be improved, compared to that of the projected image on a white screen.
Chang-Hwan Son, Yeong-Ho Ha, "Color Correction of Images Projected on a Colored Screen for Mobile Beam Projector" in Journal of Imaging Science and Technology, 2008, pp 30505-1 - 30505-11, https://doi.org/10.2352/J.ImagingSci.Technol.(2008)52:3(030505)