CIE 1960 UCS Diagram and the Müller Theory of Color Vision

Tribo-Induced Color Tuner toward Smart Lighting and Self-Powered Wireless Sensing

The color-tuning capability of solid-state lighting (SSL) systems are highly demanded for smart lighting according to the environmental conditions, as well as wireless sensing of the environmental information. In the meanwhile, state-of-the-art triboelectric nanogenerator (TENG)-based sensing systems rely on bulky and expensive devices, which require cable connections and additional power consumptions. This work aims at solving these challenges, through developing a tribo-induced color tuner that can be integrated into the vastly distributed commercial SSL system. This tribo-induced color tuner includes a concentric color conversion plate consisting of (Sr,Ca)AlSiN3:Eu phosphor and TiO2, a tribo-induced liquid lens, and a rotary freestanding sliding TENG. The color oscillation between purple and pink is achieved upon the tribo-charging by the TENG, which reveals the input mechanical motion signals. The signal can be conveniently sent by everywhere-existed lamps and processed by everyone-owned smartphone cameras or closed-circuit televisions. Through this approach, the function of wireless sensing is achieved without the need of preamplification, with no additional power supply required, as demonstrated for wireless sensing of the rotation speed. The smart lighting for underwater photographing is also demonstrated by the color-tunable SSL system with the best imaging quality achieved.

Robust Chromatic Adaptation Based Color Correction Technology for Underwater Images

Recovering correct or at least realistic colors of underwater scenes is a challenging issue for image processing due to the unknown imaging conditions including the optical water type, scene location, illumination, and camera settings. With the assumption that the illumination of the scene is uniform, a chromatic adaptation-based color correction technology is proposed in this paper to remove the color cast using a single underwater image without any other information. First, the underwater RGB image is first linearized to make its pixel values proportional to the light intensities arrived at the pixels. Second, the illumination is estimated in a uniform chromatic space based on the white-patch hypothesis. Third, the chromatic adaptation transform is implemented in the device-independent XYZ color space. Qualitative and quantitative evaluations both show that the proposed method outperforms the other test methods in terms of color restoration, especially for the images with severe color cast. The proposed method is simple yet effective and robust, which is helpful in obtaining the in-air images of underwater scenes.

Theory of wavelength discrimination in tritanopia

Many theories of color discrimination predict a discontinuity in the wavelength-discrimination function of a tritanope at the point in the spectrum at which the rate of change of the visual signal constrained to an equiluminant plane passes through zero (near 460 nm). The predicted discontinuity follows from the use of a first-order approximation for which the reciprocal of the slope of the response function that generates the visual signal is proportional to the discrimination limen. In view of the good discrimination shown by such observers elsewhere in the spectrum, however, such a singularity is impossible. I show that the inclusion of the higher-order terms produces a finite value in the 460-nm region that falls in the range of values from the literature that have been obtained experimentally.

The Abney effect: chromaticity coordinates of unique and other constant hues

We compared unique and other constant hue loci measured at a fixed retinal illuminance for the same observers. When expressed in Judd chromaticity coordinates, unique hue and constant hue data agreed. Unique blue loci were curved, and unique red and green loci were noncollinear. These data imply that unique hues are not a linear transformation of color matching functions. Linear models are only an approximation, even at a single luminance level.