Visual perception

Decline (linear with increasing CoHb level) in maximal oxygen uptake of healthy young men undergoing strenuous exercise decrements in visual perception, manual dexterity, and performance of complex sensorimotor tasks... 

Experimental exposure studies have attempted to associate various neurological effects in humans with specific trichloroethylene exposure levels. Voluntary exposures of 1 hours resulted in complaints of drowsiness at 27 ppm and headache at 81 ppm (Nomiyama and Nomiyama 1977). These are very low exposure levels, but the results are questionable because of the use of only three test subjects per dose, lack of statistical analysis, sporadic occurrence of the effects, lack of clear dose-response relationships, and discrepancies between the text and summary table in the report. Therefore, this study is not presented in Table 2-1. No effects on visual perception, two-point discrimination, blood pressure, pulse rate, or respiration rate were observed at any vapor concentration in this study. Other neurobehavioral tests were not performed, and the subjects were not evaluated following exposure. 

On a practical basis, if we wish to set up this system, we would assemble a set of "color-chips". Each color-chip would be specified by two factors, H = hue, and V/C, which is value (grayness) modified by chroma (saturation). The actual number of layers in the Munsell Color Tree was determined by "minimum perceptual difference". That is, the minimum change that produces a visual perceptible difference. This arrangement specifies all light colors as well cis the dark ones. To use such a system, one would choose the color-chip closest to the hue and saturation of the test color and thus obtain values for H and V/C. However, it was soon discovered that the system was not perfect. Reasons for this include the facts that the hues defined by Munsell are not those of the primaries of the human eye. Furthermore, Munsell was somewhat subjective in his definitions of hues. 

It was soon determined that the 1931 CIE chromaticity diagram, and lumincmce function, Y, are not representative of equal visual spacing, that is, equal changes in Y do not represent equal changes in visual perception for all values of Y. Nor do equal increments of x and y represent the same visual effect for all locations on the chromaticity diagram. In other words, there is a minimum perceptual difference on both x and y (i.e.- Ax and Ay). But, the size of Ax and Ay is not the same at all parts of the chromaticity diagram. This is the same problem that Munsell encountered and is due to the fact that the human eye is... 

The effects of catechin, epicatechin, procyanidin B2, caffeic acid, / -coumaric acid, myricetrin, and quercetrin on the color intensity and stability of malvidin 3-glucoside at a molar ratio of 1 1 under conditions similar to red wine were evaluated. " Flavan 3-ols appeared to have the lowest protective effects and flavonols the highest strong color changes were visually perceptible. " In the complexation of malvin chloride and natural polyphenols, flavonol glycosides by far exerted the best protector effect. ... 

Sandman CA, McCanne TR, Kaiser DN and Diamond B (1982). Heartrate and cardiac phase influences on visual perception. Journal of Comparative Physiological Research, 91, 189-202. 

The effect of particle size, and hence dispersion, on the coloring properties of aluminum lake dyes has been studied through quantitative measurement of color in compressed formulations [47], It was found that reduction in the particle size for the input lake material resulted in an increase in color strength, and that particles of submicron size contributed greatly to the observed effects. Analysis of the formulations using the parameters of the 1931 CIE system could only lead to a qualitative estimation of the effects, but use of the 1976 CIEL m v system provided a superior evaluation of the trends. With the latter system, the effects of dispersion on hue, chroma, lightness, and total color differences were quantitatively related to human visual perception. 

Acidity Visual perception of poor vegetative plant growth and root, soil has orange, reddish, or purple color with iron or manganese spots, some farmers can taste the acidity, dense growth of Melastoma malabathricum... 

Bender-Gestalt Test. The Bender-Gestalt is a nonverbal performance test in which the individual copies a design shown on a card. It is often used to identify a problem of visual perception and/or motor performance or minimal brain dysfunction in children. 

Frostig Developmental Test of Visual Perception. The Frostig Developmental Test of Visual Perception (FROST) measures the development of perceptual skills in children from four to eight years of age or in older children with learning difficulties. It may be administered individually (requires 30-45 minutes) or to groups (requires 40-60 minutes). 

Johansson, G. 1973. Visual perception of biological motion and a model of its analysis. Perception Psychophysics, 14,201-211. 

Carrasco, A. and Siebert, K. J. (1999). Human visual perception of haze and relationships with instrumental measurements of turbidity. Thresholds, magnitude estimation and sensory descriptive analysis of haze in model systems. Food Qual. Pref. 10, 421 436. 

Fleet, C. F. and Siebert, K. J. (2006). Effect of viewing background on visual perception of turbidity. J. Sens. Stud. 21,34-53. 

Visual Perception of Effervescence in Champagne and Other Sparkling Beverages... 

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