The lightness of a test stimulus depends in a complex manner on the context in which it is viewed. To predict lightness, it is necessary to leverage measurements of a feasible number of contextual configurations into predictions for a wider range of configurations. Here we pursue this goal, using the idea that lightness results from the visual system's attempt to provide stable information abou...

An anchoring theory of lightness perception comprehensively explains many characteristics of human visual system such as lightness constancy and its spectacular failures which are important in the perception of images. We present a novel approach to tone mapping of high dynamic range (HDR) images which is inspired by the anchoring theory. The key concept of this method is the decomposition of a...

In the present experiment we addressed the question of how the visual system determines surface lightness from luminances in the retinal image. We measured the perceived lightness of target surfaces that were embedded in custom-made checkerboards. The checkerboards consisted of 10 by 10 checks of 10 different reflectance values that were arranged randomly across the board. They were rendered un...

The coplanar ratio principle proposes that when the luminance range in an image is larger than the canonical reflectance range of 30:1, the lightness of a target surface depends on the luminance ratio between that target and its adjacent coplanar neighbor (Gilchrist, 1980). This conclusion is based on experiments in which changes in the perceived target depth produced large changes in its perce...

Two psychophysical experiments were conducted to analyze the role of color attributes in simple tasks involving color matching and discrimination. In Experiment I observers made color matches using three different adjustment control methods. The results showed that the Lightness, Chroma, Hue (LCH) and the Lightness, redness/greenness, blueness/yellowness ({L, r/g, y/b}) adjustment controls elic...

When viewing images, the relative luminance of the surround has a profound impact on the apparent contrast of the image. For this reason, photographic transparencies intended for projection in a darkened room are produced with an objective contrast substantially higher than that necessary for optimum reproduction as prints viewed in an illuminated surround. The dark surround causes the image el...

Using a paired comparison paradigm, various gamut mapping algorithms were evaluated using simple rendered images and artificial gamut boundaries. The test images consisted of simple rendered spheres floating in front of a gray background. Using CIELAB as our device-independent color space, cut-off values for lightness and chroma, based on the statistics of the images, were chosen to reduce the ...