Why human color vision cannot reliably detect cerebrospinal fluid xanthochromia

Background - Visual assessment of cerebrospinal fluid (CSF) for xanthochromia ( yellow color) is practiced by the majority of laboratories worldwide as a means of diagnosing intracranical bleeds.Methods - Colorimetric and spectrophotometric analysis of CSF samples for recognizing the presence of bilirubin either in low concentrations or in the presence of hemolysed blood.Results - The experiments provide the physiological and colorimetric basis for abandoning visual assessment of CSF for xanthochromia.Conclusion - We strongly recommend relying on spectrophotometry as the analytical method of choice

Digital Color Imaging

This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided

ジュンムラサキ キセキジョウ ニ メモラレタ ホショクシュハチョウ ノ シキドザヒョウ

One of the numerical color specification is represented in the CIE system by the dominant wavelength (DWL) and excitation purity respectively. The DWL usually is found at the intersection of the spectrum locus with a straight line drawn from illuminant point through the given color point. However, in the case of purples, a line drawn in this manner does not intersect the spectrum locus. The DWL is found at the intersection of the spectrum locus with a straight line drawn from the given color point through the illuminant point and extended, which is specified as a complementary wavelength (CDWL). lf the points defining the CDWL are prepared on the purple boundary in advance, it will be not necessary to extend a line from the illuminant point to the spectum locus. For that, authers obtained eight kinds of the numerical tables representing the trichromatic coefficients of the CDWL for ilhiminant A, B, C and D_ according to the CIE 1931 standard colorimetric system and the CIE 1964 supplementary standard colorimetric system

Colour constancy using von Kries transformations: colour constancy "goes to the Lab"

Colour constancy algorithms aim at correcting colour towards a correct perception within scenes. To achieve this goal they estimate a white point (the illuminant's colour), and correct the scene for its in uence. In contrast, colour management performs on input images colour transformations according to a pre-established input pro le (ICC pro le) for the given con- stellation of input device (camera) and conditions (illumination situation). The latter case presents a much more analytic approach (it is not based on an estimation), and is based on solid colour science and current industry best practises, but it is rather in exible towards cases with altered conditions or capturing devices. The idea as outlined in this paper is to take up the idea of working on visually linearised and device independent CIE colour spaces as used in colour management, and to try to apply them in the eld of colour constancy. For this purpose two of the most well known colour constancy algorithms White Patch Retinex and Grey World Assumption have been ported to also work on colours in the CIE LAB colour space. Barnard's popular benchmarking set of imagery was corrected with the original imple- mentations as a reference and the modi ed algorithms. The results appeared to be promising, but they also revealed strengths and weaknesses

Fractal Dimensions in Perceptual Color Space: A Comparison Study Using Jackson Pollock's Art

The fractal dimensions of color-specific paint patterns in various Jackson Pollock paintings are calculated using a filtering process which models perceptual response to color differences (\Lab color space). The advantage of the \Lab space filtering method over traditional RGB spaces is that the former is a perceptually-uniform (metric) space, leading to a more consistent definition of ``perceptually different'' colors. It is determined that the RGB filtering method underestimates the perceived fractal dimension of lighter colored patterns but not of darker ones, if the same selection criteria is applied to each. Implications of the findings to Fechner's 'Principle of the Aesthetic Middle' and Berlyne's work on perception of complexity are discussed.Comment: 21 pp LaTeX; two postscript figure