Engineering data compendium. Human perception and performance. User's guide

The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design and military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from the existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by systems designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is the first volume, the User's Guide, containing a description of the program and instructions for its use

An investigation and analysis of visual sensitivity under conditions of glare

Imperial Users onl

Methods for assessing the effects of spatial luminance patterns on perceived qualities of concert lighting

This paper presents experimental approaches for evaluating concert lighting from the viewpoints of audience members and performers in Cambridge King's College Chapel. We develop image zoning and abstraction techniques to quantify and interpret photometric data acquired under four different electric lighting conditions. Assessed by 78 participants, these lighting scenarios are compared across six different viewing positions using a set of structured questionnaires. Ordered logistic regression modelling shows that the ratios and functions describing uniformity, brightness and light patterns are common explanatory variables for predicting perceived visual clarity, visual uniformity, brightness and spatial intimacy. Uniformity-related attributes are observed to be among the strongest variables for all these perceived qualities, except for visual clarity, which is better explained by acuity-related measures. These experimental results confirm the applicability of our approaches, highlighting the importance of combining multiple methods and integrating complex architectural situations into the process of understanding luminous appearance. Cambridge Trus

Chromatic assimilation: spread light or neural mechanism?

AbstractChromatic assimilation is the shift in color appearance of a test field toward the appearance of nearby light. Possible explanations of chromatic assimilation include wavelength independent spread light, wavelength-dependent chromatic aberration and neural summation. This study evaluated these explanations by measuring chromatic assimilation from a concentric-ring pattern into an equal-energy-white background, as a function of the inducing rings’ width, separation, chromaticity and luminance. The measurements showed, in the s direction, that assimilation was observed with different inducing-ring widths and separations when the inducing luminance was lower or higher than the test luminance. In general, the thinner the inducing rings and the smaller their separation, the stronger the assimilation in s. In the l direction, either assimilation or contrast was observed, depending on the ring width, separation and luminance. Overall, the measured assimilation could not be accounted for by the joint contributions from wavelength-independent spread light and wavelength-dependent chromatic aberration. Spatial averaging of neural signals explained the assimilation in s reasonably well, but there were clear deviations from neural spatial averaging for the l direction

The photometric evaluation of flashing light sources in relation to their conspicuity

Imperial Users onl

The Venetian blind effect, binocular luster, and binocular rivalry

When one views a square-wave grating and changes the average luminance or contrast of the monocular images relative to each other, at least three perceptual phenomena occur. These are the Venetian blind effect, or a perceived rotation of the bars around individual vertical axes; binocular luster, or a perceived shimmering; and binocular rivalry, or an alternating perception between the views of the two eyes. In this paper, it is shown that increasing the dichoptic luminance modulation leads to these three phenomena in sequence, while increasing dichoptic contrast modulation generally only leads to perceived rotation. It is also shown that average luminance and contrast are not the deciding factors in when the three perceptual phenomena occur. Perception of luster and rivalry occur when the light bars in the grating dichoptically straddle the background luminance, with little impact of the dark bars, as demonstrated when light bars or dark bars are presented in isolation. Also when presented in isolation, perceived rotation ceases when the bars dichoptically straddle the background luminance. The deciding factor is shown not to be the adaptation level of the participant and instead to be this relation of the monocular images to the background. The patterns for perceived rotation versus binocular luster and binocular rivalry suggest separate mechanisms in the visual system. Possible mechanisms are suggested, and experimental manipulations are proposed that would discriminate between them