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Sylvia Pont; An ecologically valid description of the light field. Journal of Vision 2011;11(11):345. doi: 10.1167/11.11.345.
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© ARVO (1962-2015); The Authors (2016-present)
Situational awareness is composed of several (interrelated) generic frameworks. The luminosity framework is an awareness of the luminous environment or light field. That one indeed perceives the luminous environment is evident from the fact that observers have implicit expectations concerning the appearance of objects as they are introduced into the scene [Koenderink et al., Perception 36, 2007; Pont et al., ECVP, 2010]. Currently, in state of the art computer graphics and in perception research, one often takes recourse to brute force methods to describe luminous environments, e.g. using spherical harmonic approximations (a sort of Fourier analysis of its directional frequency components as represented on a sphere). Although the relationship between these computationally very efficient mathematical components and the constituents of the luminosity framework should certainly be addressed, I propose to investigate the luminosity framework from a different starting point by using a combination of the concepts “flow”, “scale”, “zones” and “texture” of the luminous environment. Since these concepts were actually formulated to describe the visual appearance of the luminous environment, they seem to be more suitable parameters than the mathematically elegant but perceptually alien spherical harmonics. The “flow” describes the average direction and how it changes through space. The “flow” was defined mathematically as the average flux transport as a function of position in 3D space. In former research we measured it as the set of first order spherical harmonic components and visualized it using light tubes. The “scale” is a term used to describe the diffuseness of the luminous environment. The concept of “zones” refers to regions of different types of luminance, of which one or several may exist in a single scene. The “texture” concerns a statistical summary of the fine structure of the luminous environment. Applications of this novel description of the light field will be discussed.
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