Psychophysical estimates of the number of spectral-reflectance basis functions needed to reproduce natural scenes

Nascimento, Sérgio M. C.; Foster, David H.; Amano, Kinjiro

doi:10.1364/josaa.22.001017

Cited by 42 publications

(37 citation statements)

References 25 publications

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“…The link functions for the global and local models are different, but this has little effect here. Figure 8 shows performance by a normal human observer discriminating between images of natural colored scenes and approximations to those images synthesized with varying levels of fidelity [27]. The symbols are the proportion of correct responses out of 200 trials as a function of the number of components in the approximation in reverse order (replotted from unpublished source data summarized in [27]).…”

Section: Goldfish Horizontal-cell Feedback Currentmentioning

confidence: 99%

Nonparametric Estimates of Biological Transducer Functions

Foster¹,

Żychaluk

2007

IEEE Signal Process. Mag.

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Section: Goldfish Horizontal-cell Feedback Currentmentioning

confidence: 99%

Nonparametric Estimates of Biological Transducer Functions

Foster¹,

Żychaluk

2007

IEEE Signal Process. Mag.

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“…Nonuniformity of object colors (texture) and their environment seems to be the rule rather than the exception. [9][10][11] Therefore, a logical next step in color emotion studies is the extension from uniform color (UC) toward color texture (CT). So far, the role of texture in color emotion has received only little attention.…”

Section: Introductionmentioning

confidence: 99%

Texture affects color emotion

Lucassen

Gevers

Gijsenij

2010

Color Research & Application

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Several studies have recorded color emotions in subjects viewing uniform color (UC) samples. We conduct an experiment to measure and model how these color emotions change when texture is added to the color samples. Using a computer monitor, our subjects arrange samples along four scales: warm-cool, masculine-feminine, hard-soft, and heavy-light. Three sample types of increasing visual complexity are used: UC, grayscale textures, and color textures (CTs). To assess the intraobserver variability, the experiment is repeated after 1 week. Our results show that texture fully determines the responses on the Hard-Soft scale, and plays a role of decreasing weight for the masculine-feminine, heavy-light, and warm-cool scales. Using some 25,000 observer responses, we derive color emotion functions that predict the group-averaged scale responses from the samples' color and texture parameters. For UC samples, the accuracy of our functions is significantly higher (average R 2 ¼ 0.88) than that of previously reported functions applied to our data. The functions derived for CT samples have an accuracy of R 2 ¼ 0.80. We conclude that when textured samples are used in color emotion studies, the psychological responses may be strongly affected by texture.

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“…Using just three classes of broadly tuned cone photoreceptors, the primate visual system is able to distinguish the spectra of natural lights and objects sufficiently , while maintaining good spatial resolution, and providing the means to identify objects by their colors despite variations in ambient lights and surrounding scenes (Zaidi, 1998(Zaidi, , 2001. More classes of photoreceptors would improve the sampling of natural spectra (Nascimento, Foster, & Amano, 2005), but would seriously compromise spatial resolution. Generating narrow color tuning in functionally specialized cortical regions affords rapid interval decoding without losing these features.…”

Section: Evolution Of Neural Computations: Mantis Shrimp and Human Comentioning

confidence: 99%

Colour vision in mantis shrimps: understanding one of the most complex visual systems in the world

Thoen¹

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Stomatopods (commonly known as mantis shrimps) have one of the most complex visual systems in the animal kingdom with up to 20 different photoreceptor types and the ability to see both linear and circular polarized light. The eye of a stomatopod is divided into three different parts; a dorsal and a ventral hemisphere divided up by 6 distinct rows of specialised ommatidia (visual units) termed the midband. The midband contains a complex array of up to 12 spectral receptors with maximum sensitivities ranging from the ultraviolet (UV) to the far-red (300-700 nm), in addition to achromatic receptors of which several are sensitive to different forms of polarized light. The abundance of spectral receptors has puzzled researchers, as it seemed excessive even for an animal living in a spectrally rich environment such as the coral reef. Furthermore, theoretical analyses suggest that there is really no need to have more than 4-7 receptors to have satisfactory colour vision in the 300-400 nm spectral range. Our increasing knowledge of polarization sensitivity is rapidly expanding the theme of photoreceptor proliferation with up to six channels of polarization information from a combination of midband and hemisphere receptors.The aim of this thesis was to investigate how stomatopods process and analyse chromatic and polarization information using a complementary approach of behavioural, electrophysiological and neuroanatomical techniques. A comparison of spectral sensitivities across species in the superfamily Gonodactyloidea was carried out in Chapter 2. This study showed that their spectral sensitivities remain very similar between species, with narrow, steeply shaped sensitivity curves spread evenly throughout the spectrum, suggesting there is a benefit of having uniform sampling of all wavelengths. Behavioural experiments were performed to test stomatopod spectral discrimination in Chapter 3, and this was found to be surprisingly poor, both compared to other animals and to theoretical modelling. To investigate if the poor discrimination was due to the spectral shape of the stimuli, more natural-shaped stimuli (with step-shaped spectra instead of the conventional peakshaped spectra) were tested in similar experiments (Chapter 4). However, these experiments yielded similar results to the ones obtained in Chapter 3. The electrophysiological and behavioural results suggest that the stomatopod visual system may use a simpler, serial processing system unlike the "conventional" opponency system known from other animals and may be the reason for why the spectral and polarization space must be covered by several channels.While such as system may appear exceptional, there are similarities between this system and they way primates process colour, only at different steps in the processing pathway (Chapter 5). Using an interval-decoding scheme coupled with the narrow, binned spectral sensitivities of stomatopods could allow quick and precise colour judgements but at the cost of very fine discrimination. 3As very little wa...

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Psychophysical estimates of the number of spectral-reflectance basis functions needed to reproduce natural scenes

Cited by 42 publications

References 25 publications

Nonparametric Estimates of Biological Transducer Functions

Nonparametric Estimates of Biological Transducer Functions

Texture affects color emotion

Colour vision in mantis shrimps: understanding one of the most complex visual systems in the world

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