Invariant Image Improvement by sRGB colour space sharpening

Finlayson, Graham D., Drew, Mark S. and Lu, Cheng (2005) Invariant Image Improvement by sRGB colour space sharpening. In: 10th Congress of the International Colour Association AIC Colour 05, 2005-05-08 - 2005-05-13.

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Reasoning from image formation, we have shown that there exists a greyscale image – the invariant image – that depends only on the reflectances in the scene. Since illumination dependence is removed, one aspect of the invariant image is that shadows are effectively removed. Moreover, given either a calibration, or clean data with good noise statistics, this invariant is easily found. However, we found that the performance was much poorer on ordinary images that include the typical nonlinear processing in cameras. The contribution of this paper is that we can find a good invariant notwithstanding input image nonlinearities. Our strategy is to follow standard colorimetric procedure and convert image RGBs to the appropriate colour space for our method. We do this by converting first to the linear sRGB colour space and then concatenating conversion to XYZ tristimulus values by a spectral sharpening transform. We handle a suite of images which were intractable to the original method and are now able to find a shadow-free intrinsic reflectance image.

Item Type: Conference or Workshop Item (Poster)
Faculty \ School: Faculty of Science > School of Computing Sciences
UEA Research Groups: Faculty of Science > Research Groups > Colour and Imaging Lab
Faculty of Science > Research Groups > Interactive Graphics and Audio
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Depositing User: Vishal Gautam
Date Deposited: 20 Jul 2011 11:45
Last Modified: 20 Jun 2023 14:32

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