Estimation of illumination characteristics

Estimation of illumination characteristics

The description of the relation between the one-parameter subgroups of a group and the differential operators in the Lie-algebra of the group is one of the major topics in Lie-theory. We use this framework to derive a partial differential equation which describes the relation between the time-change of the spectral characteristics of the illumination source and the change of the color pixels in...

Rank-Based Illumination Estimation

A new two-stage illumination estimation method based on the concept of rank is presented. The method first estimates the illuminant locally in subwindows using a ranking of digital counts in each color channel and then combines local subwindow estimates again based on a ranking of the local estimates. The proposed method unifies the MaxRGB and Grayworld methods. Despite its simplicity, the perf...

Realtime Estimation of Illumination Images Using Illumination Eigenspace

An illumination irnagc, which is a part of intrinsic images, represents the effect of a lighting condition of thc sccnc. To propcrly handlc illumination cffccts such as cast-shadows in the input image, image manipulation using thc illumination imagc is only natural, since it describes variation of lighting effects from a rcflcctancc imagc which can bc considered as an image under the standard i...

Global Illumination via Density Estimation

Removing Outliers in Illumination Estimation

A method of outlier detection is proposed as a way of improving illumination-estimation performance in general, and for scenes with multiple sources of illumination in particular. Based on random sample consensus (RANSAC), the proposed method (i) makes estimates of the illumination chromaticity from multiple, randomly sampled sub-images of the input image; (ii) fits a model to the estimates; (i...