In this paper, we show that a color image model we recently proposed explains the existence of color lines and predicts that they will have a slope of one. We present experimental results verifying this on several image datasets by showing that images segmented into blocks are often well-described by lines of slope one, that pixels with similar local averages fall on a line of slope one, and that, when all the pixels are normalized to have a local average of zero, they all fall on a line of slope one. We also discuss the image formation models that lead to this prediction and address some of the difficulties previously encountered in using image formation models to explain color lines.
Megan M. Fuller, Jae S. Lim, "Explanation of Color Lines Based on a Simple Color Image Model" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Color Imaging XXIII: Displaying, Processing, Hardcopy, and Applications, 2018, pp 296-1 - 296-5, https://doi.org/10.2352/ISSN.2470-1173.2018.16.COLOR-296