“Color2Gray: salience-preserving color removal” by Gooch, Olsen, Tumblin and Gooch

  • ©Amy Gooch, Sven C. Olsen, Jack Tumblin, and Bruce Gooch




    Color2Gray: salience-preserving color removal



    Visually important image features often disappear when color images are converted to grayscale. The algorithm introduced here reduces such losses by attempting to preserve the salient features of the color image. The Color2Gray algorithm is a 3-step process: 1) convert RGB inputs to a perceptually uniform CIE L*a*b* color space, 2) use chrominance and luminance differences to create grayscale target differences between nearby image pixels, and 3) solve an optimization problem designed to selectively modulate the grayscale representation as a function of the chroma variation of the source image. The Color2Gray results offer viewers salient information missing from previous grayscale image creation methods.


    1. Adobe Photoshop, 2004. Photoshop: Converting color images to black and white. http://www.adobe.com/tips/phs8colorbw/main.html.Google Scholar
    2. Brown. R., 2004. Photoshop tips: Seeing in black & white. http: //www.russellbrown.com/tips_tech.html.Google Scholar
    3. Fattal. R., Lischinski, D., and Werman, M. 2002. Gradient domain high dynamic range compression. ACM Transactions on Graphics 21, 3 (July), 249–256. Google ScholarDigital Library
    4. Healey, C. G., and Enns, J. T. 1996. A perceptual colour segmentation algorithm. Tech. Rep. TR-96-09, UBC CS. Google ScholarDigital Library
    5. Heckbert. P. S. 1982. Color Image Quantization for Frame Buffer Display. In Proceedings of SIGGRAPH, 297–307. Google ScholarDigital Library
    6. Levin, A., Lischinski, D., and Weiss. Y. 2004. Colorization using optimization. In ACM Transactions on Graphics. Google ScholarDigital Library
    7. Livingstone, M., Ed. 2002. Vision and Art: The Biology of Seeing. Harry N. Abrams, Inc., Publishers.Google Scholar
    8. Lotto, R. B., and Purves. D. 1999. The effects of color on brightness. Nature Neurosci. 2, 11, 1010–1014.Google ScholarCross Ref
    9. Pérez, P., Gangnet. M., and Blake. A. 2003. Poisson image editing. ACM Transactions on Graphics 22, 3 (July), 313–318. Google ScholarDigital Library
    10. Power, J. L., West, B. S., Stollnitz. E. J., and Salesin, D. H. 1996. Reproducing color images as duotones. In Proceedings of SIGGRAPH, ACM Press, 237–248. Google ScholarDigital Library
    11. Rasche, K., Geist, R., and Westall. J. 2005. Detail preserving reproduction of color images for monochromats and dichromats. IEEE Comput. Graph. Appl. 25, 3. Google ScholarDigital Library
    12. Rasche, K., Geist, R., and Westall, J. 2005. Re-coloring images for gamuts of lower dimension. Eurographics/Computer Graphics Forum 24, 3.Google ScholarCross Ref
    13. Shewchuk, J. R. 1994. An introduction to the conjugate gradient method without the agonizing pain. Tech. rep., Pittsburgh, PA. Google ScholarDigital Library
    14. Teschioni, A., Regazzoni, C. S., and Stringa, E. 1997. A Markovian approach to color image restoration based on space filling curves. In International Conference on Image Processing Proceedings, vol. 2, 462–465.Google Scholar
    15. Volk, C., 2000. Adobe Photoshop Tip of the Week Tutorial. http://www.carlvolk.com/photoshop21.htm.Google Scholar
    16. Wyszecki, G., and Stiles, W. S., Eds. 2000. Color Science: Concepts and Methods, Quantitative Data and Formulae. Wiley-Interscience.Google Scholar

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