Contrast Enhancing Colour to Grey

  • Ali Alsam
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5575)


A spatial algorithm to convert colour images to greyscale is presented. The method is very fast and results in increased local and global contrast. At each image pixel, three weights are calculated. These are defined as the difference between the blurred luminance image and the colour channels: red, green and blue. The higher the difference the more weight is given to that channel in the conversion. The method is multi-resolution and allows the user to enhance contrast at different scales. Results based on three colour images show that the method results in higher contrast than luminance and two spatial methods: Socolinsky and Wolff [1,2] and Alsam and Drew [3].


Colour Space Image Pixel Colour Channel Contrast Enhance White Image 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Socolinsky, D.A., Wolff, L.B.: A new visualization paradigm for multispectral imagery and data fusion. In: CVPR, pp. I:319–324 (1999)Google Scholar
  2. 2.
    Socolinsky, D.A., Wolff, L.B.: Multispectral image visualization through first-order fusion. IEEE Trans. Im. Proc. 11, 923–931 (2002)CrossRefGoogle Scholar
  3. 3.
    Alsam, A., Drew, M.S.: Fastcolour2grey. In: 16th Color Imaging Conference: Color, Science, Systems and Applications, Society for Imaging Science & Technology (IS&T)/Society for Information Display (SID) joint conference, Portland, Oregon, pp. 342–346 (2008)Google Scholar
  4. 4.
    Bala, R., Eschbach, R.: Spatial color-to-grayscale transform preserving chrominance edge information. In: 14th Color Imaging Conference: Color, Science, Systems and Applications, pp. 82–86 (2004)Google Scholar
  5. 5.
    Hunt, R.W.G.: The Reproduction of Colour, 5th edn. Fountain Press, England (1995)Google Scholar
  6. 6.
    Lillesand, T.M., Kiefer, R.W.: Remote Sensing and Image Interpretation, 2nd edn. Wiley, New York (1994)Google Scholar
  7. 7.
    Grundland, M., Dodgson, N.A.: Decolorize: Fast, contrast enhancing, color to grayscale conversion. Pattern Recognition 40(11), 2891–2896 (2007)Google Scholar
  8. 8.
    Di Zenzo, S.: A note on the gradient of a multi-image. Comp. Vision, Graphics, and Image Proc. 33, 116–125 (1986)CrossRefzbMATHGoogle Scholar
  9. 9.
    Connah, D., Finlayson, G.D., Bloj, M.: Seeing beyond luminance: A psychophysical comparison of techniques for converting colour images to greyscale. In: 15th Color Imaging Conference: Color, Science, Systems and Applications, pp. 336–341 (2007)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Ali Alsam
    • 1
  1. 1.Sør-Trøndelag University CollegeTrondheimNorway

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