Adaptation to the Amplitude Spectrum Slope of Natural Scenes in Modified Reality

Within the spectrum of a natural image, the amplitude of modulation decreases with spatial frequency. The speed of such an amplitude decrease, or the amplitude spectrum slope, of an image affects the perceived aesthetic value. Additionally, a human observer would consider a symmetric image more appealing than they would an asymmetric one. We investigated how these two factors jointly affect aesthetic preferences by manipulating both the amplitude spectrum slope and the symmetric level of images to assess their effects on aesthetic preference on a 6-point Likert scale. Our results showed that the preference ratings increased with the symmetry level but had an inverted U-shaped relation to amplitude spectrum slope. In addition, a strong interaction existed between symmetry level and amplitude spectrum slope on preference rating, in that symmetry can amplify the amplitude spectrum slope’s effects. A quadratic function of the spectrum slope can describe such effects. That is, preference is an inverted U-shaped function of spectrum slope whose intercept is determined by the number of symmetry axes. The modulation depth of the quadratic function manifests the interaction between the two factors.

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Center-surround effects in human discrimination of amplitude spectrum slope

Journal of Vision ◽

10.1167/7.9.967 ◽

2010 ◽

Vol 7 (9) ◽

pp. 967-967

Author(s):

A. Johnson ◽

B. Hansen ◽

D. Ellemberg

Keyword(s):

Amplitude Spectrum ◽

Spectrum Slope

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Benefits of a trans-saccadic masks: Preventing the desensitization effects of amplitude spectrum slope discrimination when using physical masks

Journal of Vision ◽

10.1167/11.11.1195 ◽

2011 ◽

Vol 11 (11) ◽

pp. 1195-1195

Author(s):

B. Richard ◽

A. Johnson

Keyword(s):

Amplitude Spectrum ◽

Spectrum Slope

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Immersion in Modified Reality: Sensitivity to the Slope (α) of the Amplitude Spectrum is Dependent on the α of Recently Viewed Environments

10.1101/2021.08.19.456985 ◽

2021 ◽

Author(s):

Bruno Richard ◽

Patrick Shafto

Keyword(s):

Visual System ◽

Visual Processing ◽

A Priori ◽

Amplitude Spectrum ◽

Natural Scenes ◽

Experimental Conditions ◽

Head Mounted Display ◽

Statistical Regularities ◽

Observer Model

Scenes contain many statistical regularities that, if accounted for by the visual system, could greatly benefit visual processing. One such statistic to consider is the orientation-averaged slope (α) of the amplitude spectrum of natural scenes. Human observers are differently sensitive to αs, and they may utilize this statistic when processing natural scenes. Here, we explore whether discrimination sensitivity to α is associated with the recently viewed environment. Observers were immersed, using a Head-Mounted Display, in an environment that was either unaltered or had its average α steepened or shallowed. Discrimination thresholds were affected by the average shift in α: a steeper environment decreased thresholds for very steep reference αs while a shallower environment decreased thresholds for shallow values. We modelled these data with a Bayesian observer model and explored how different prior shapes may influence the ability of the model to fit observer thresholds. We explore three potential prior shapes: unimodal, bimodal and trimodal modified-PERT distributions and found the bimodal prior to best-capture observer thresholds for all experimental conditions. Notably, the prior modes' position was shifted following adaptation, which suggests that a priori expectations for α are sufficiently malleable to account for changes in the average α of the recently viewed scenes.

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Color constancy in natural scenes explained by global image statistics

Visual Neuroscience ◽

10.1017/s0952523806233455 ◽

2006 ◽

Vol 23 (3-4) ◽

pp. 341-349 ◽

Cited By ~ 26

Author(s):

DAVID H. FOSTER ◽

KINJIRO AMANO ◽

SÉRGIO M.C. NASCIMENTO

Keyword(s):

Imaging System ◽

Amplitude Spectrum ◽

Color Constancy ◽

Discrimination Performance ◽

Color Temperature ◽

Test Surface ◽

Psychophysical Experiment ◽

Natural Scenes ◽

Image Statistics ◽

The Mean

To what extent do observers' judgments of surface color with natural scenes depend on global image statistics? To address this question, a psychophysical experiment was performed in which images of natural scenes under two successive daylights were presented on a computer-controlled high-resolution color monitor. Observers reported whether there was a change in reflectance of a test surface in the scene. The scenes were obtained with a hyperspectral imaging system and included variously trees, shrubs, grasses, ferns, flowers, rocks, and buildings. Discrimination performance, quantified on a scale of 0 to 1 with a color-constancy index, varied from 0.69 to 0.97 over 21 scenes and two illuminant changes, from a correlated color temperature of 25,000 K to 6700 K and from 4000 K to 6700 K. The best account of these effects was provided by receptor-based rather than colorimetric properties of the images. Thus, in a linear regression, 43% of the variance in constancy index was explained by the log of the mean relative deviation in spatial cone-excitation ratios evaluated globally across the two images of a scene. A further 20% was explained by including the mean chroma of the first image and its difference from that of the second image and a further 7% by the mean difference in hue. Together, all four global color properties accounted for 70% of the variance and provided a good fit to the effects of scene and of illuminant change on color constancy, and, additionally, of changing test-surface position. By contrast, a spatial-frequency analysis of the images showed that the gradient of the luminance amplitude spectrum accounted for only 5% of the variance.

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Aesthetic Judgement of Orientation in Modern Art

i-Perception ◽

10.1068/i0447aap ◽

2012 ◽

Vol 3 (1) ◽

pp. 18-24 ◽

Cited By ~ 6

Author(s):

George Mather

Keyword(s):

Modern Art ◽

Amplitude Spectrum ◽

Fourier Amplitude ◽

Physical Measure ◽

Aesthetic Judgement ◽

Correct Orientation ◽

Perfect Performance ◽

Fourier Amplitude Spectrum ◽

The Impact ◽

Spectrum Slope

When creating an artwork, the artist makes a decision regarding the orientation at which the work is to be hung based on their aesthetic judgement and the message conveyed by the piece. Is the impact or aesthetic appeal of a work diminished when it is hung at an incorrect orientation? To investigate this question, Experiment 1 asked whether naïve observers can appreciate the correct orientation (as defined by the artist) of 40 modern artworks, some of which are entirely abstract. Eighteen participants were shown 40 paintings in a series of trials. Each trial presented all four cardinal orientations on a computer screen, and the participant was asked to select the orientation that was most attractive or meaningful. Results showed that the correct orientation was selected in 48% of trials on average, significantly above the 25% chance level, but well below perfect performance. A second experiment investigated the extent to which the 40 paintings contained recognisable content, which may have mediated orientation judgements. Recognition rates varied from 0% for seven of the paintings to 100% for five paintings. Orientation judgements in Experiment 1 correlated significantly with “meaningful” content judgements in Experiment 2: 42% of the variance in orientation judgements in Experiment 1 was shared with recognition of meaningful content in Experiment 2. For the seven paintings in which no meaningful content at all was detected, 41% of the variance in orientation judgements was shared with variance in a physical measure of image content, Fourier amplitude spectrum slope. For some paintings, orientation judgements were quite consistent, despite a lack of meaningful content. The origin of these orientation judgements remains to be identified.

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