This article uses multispectral techniques to investigate color processing in two individuals possessing photopigment genotypes allowing potential human tetrachromacy. In our investigations we measure spectral reflectances from empirically reproduced color sensations of potential tetrachromat observers, and investigate color processing basis functions underlying the observed set of tetrachromat spectra. Our investigations provide new empirical and quantitative methods for estimating trichromat individual's personalized spectral sensitivities, and, as shown in one potential tetrachromat examined, permit estimation of cone response sensitivities for cases that may not conform to the kind of standard dimensional solutions typically associated with trichromat models.
Color imaging is such a ubiquitous capability in daily life that a general preference for color over black-and-white images is often simply assumed. However, tactical reconnaissance applications that involve visual detection and identification have historically relied on spatial information alone. In addition, realtime transmission over narrow communication channels often restricts the amount of image data, requiring tradeoffs in spectral vs. spatial content. For these reasons, an assessment of the discrimination differences between color and monochrome systems is of significant interest to optimize the visual detection and identification of objects of interest. We demonstrate the amount of visual image "utility" difference provided by color systems through a series of subjective experiments that pair spatially degraded color images with a reference monochrome sample. The quality comparisons show a performance improvement in intelligence value equivalent to that achieved from a spatial improvement of about a factor of two (approximately 1.0 NIIRS). Observers were also asked to perform specific detection tasks with both types of systems and their performance and confidence results were measured. On average, a 25 percent accuracy improvement and a 30 percent corresponding confidence improvement were measured for the color presentation vs. the same image presented in black-and-white (monochrome).
This paper presents multispectral imaging as an alternative to conventional color imaging that showed deficiencies. Thermal infrared images have useful signatures are insensitive to different illuminations and viewing directions. Multispectral imaging by the information fusion of the visible images and thermal infrared images provides rich data information that can be used in face recognition. Comparatively to traditional face recognition, multispectral imaging can separate illumination and reflectance information of facial images. The use of fusion of visible and thermal images in face recognition shows better performance than traditional imagery.
Fourier optics system have already been recognized as an efficient solution to measure rapidly multispectral bidirectional reflectance distribution function (BRDF) of any kind of surface with very high angular resolution. This capacity is useful to study complex BRDF behaviors in particular for anisotropic surfaces. Measurement of the BRDF polarization dependence is useful to understand better the scattering processes involved in the different types of samples. In the proposed paper we show that polarimetric spectral BRDF (pBRDF) measurements are also possible using such instruments. We evaluate the accuracy of the system using black glass surface. Examples of pBRDF measurements on different types of samples (color shifting paints, car paints and gloss reference samples) are presented.
We demonstrate the sufficiency of using as few as five LEDs of distinct spectra for color-accurate multispectral lighting reproduction and solve for the optimal set of five from 11 such commercially available LEDs. We leverage published spectral reflectance, illuminant, and camera spectral sensitivity datasets to show that two approaches of lighting reproduction, matching illuminant spectra directly and matching material color appearance observed by one or more cameras or a human observer, yield the same LED selections. Our proposed optimal set of five LEDs includes red, green, and blue with narrow emission spectra, along with white and amber with broader spectra.