Colour statistics of natural and man‐made surfaces

Abstract

The reflectance spectra of natural and man‐made surfaces are highly constrained. Statistical analyses have been conducted that confirm that the surface reflectance spectra form a set of band‐limited functions with a frequency limit of approximately 0.02 cycles/nm. The reflectance spectra can be represented by a linear‐model framework and are adequately described by 6‐12 basis functions. However, the spectral properties of surfaces are not so constrained as to allow the human visual system to recover the surface properties from cone excitations. Furthermore, trichromatic colour devices such as scanners and cameras can only capture illumination‐specific colour information.

Perceptual Limits on Low-Dimensional Models of Munsell Reflectance Spectra

“…Some representations of its spectra have been shown to include natural spectra, such as those from flowers, flower clusters, leaves, and berries (Jaaskelainen et al 1990). Previous studies of the Munsell set have found that the number of basis functions needed to approximate its spectra ranges from 3 to 8, depending on the criterion of fit and whether part or all of the set was used (Cohen 1964;Maloney 1986;Parkkinen et al 1989;Jaaskelainen et al 1990;Usui et al 1992;Vrhel et al 1994;Lenz et al 1996;Owens et al 2000;Westland et al 2000;Romney and Indow 2003). In all these studies, however, the adequacy of the approximation was based on theoretical criteria, rather than on psychophysical measurement.…”

Spectral characteristics of computer screen photoassisted classification

“…10,11,16 The intensities measured in this way contain the spectral information that would allow the reconstruction, but also the spectral characteristics of the platform embedded in the signature. of the intensity vectors containing the spectral features of the substances, instead of performing a formal spectral reconstruction.…”

Group theory and geometric psychology

“…Since the pioneering contributions of Cohen (1964) and Maloney (1986), attempts at measuring the statistics of natural reflectance spectra have been performed in several laboratories (Parkkinen et al 1989;Westland et al 2000). Two crucial questions have been raised: how many basis functions are practically necessary to fully capture the variability of natural reflectances, and how does the abstract space defined by such bases relate to the coding of colour signals by the cones and the chromatically-opponent channels in the visual system?…”