Colour image gradient regression reintegration

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Suppose we process an image and alter the image gradients in each colour channel R,G,B. Typically the two new x and y component fields p,q will be only an approximation of a gradient and hence will be nonintegrable. Thus one is faced with the problem of reintegrating the resulting pair back to image, rather than derivative of image, values. This can be done in a variety of ways, usually involving some form of Poisson solver. Here, in the case of image sequences or video, we introduce a new method of reintegration, based on regression from gradients of log-images. The strength of this idea is that not only are Poisson reintegration artifacts eliminated, but also we can carry out the regression applied to only thumbnail images. The novel approach here is to regress derivatives (using only thumbnails) and then replace reintegration itself by the much simpler use of the resulting regression coefficients on non-derivative, full-size images. We investigate the utility of the method by applying it to the intrinsic-image problem as a first test, and then also to the night-to-day problem as a second test. We find that the new algorithm performs well, and is fast. Moreover eliminating Poisson artifacts results in clearer, more sharp output images that can show far less ghosting.

Original languageEnglish
Title of host publicationCIC 2018 - 26th Color and Imaging Conference
Subtitle of host publicationColor Science and Engineering Systems, Technologies, and Applications, Technical Papers and Proceedings
PublisherSociety for Imaging Science and Technology
Pages225-230
Number of pages6
Volume2018-November
ISBN (Electronic)9780892083374
DOIs
Publication statusPublished - 12 Nov 2018
Event26th Color and Imaging Conference: Color Science and Engineering Systems, Technologies, and Applications, CIC 2018 - Vancouver, Canada
Duration: 12 Nov 201816 Nov 2018

Conference

Conference26th Color and Imaging Conference: Color Science and Engineering Systems, Technologies, and Applications, CIC 2018
CountryCanada
CityVancouver
Period12/11/1816/11/18

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