Statistical correlates of perceived gloss in natural images (original) (raw)

Effects of head motion and stereo viewing on perceived glossiness

Journal of Vision, 2010

Many of the previous studies on glossiness perception have focused on glossiness from a single stimulus image. However, the essence of glossiness perception should be the estimation of the surface reflectance properties, which can be estimated computationally from luminance obtained at multiple viewpoints. Thus, the human visual system could also compute glossiness based on retinal images at different eye locations, which are caused by the observer's head motion and stereo viewing. We found that perceived glossiness is strongly enhanced by temporal changes of the retinal image caused by the observer's head motion and image differences between the two eyes in stereo viewing. These findings suggest that the human visual system utilizes rational methods for the perception of surface glossiness. Our data also suggest that the combination of multiple retinal images plays an important role in glossiness perception, just as it is assumed to do in 3D shape perception (i.e., 3D shape perception from binocular disparity and that from motion parallax).

Image Statistics and the Fine Lines of Material Perception

i-Perception, 2016

We experience vivid percepts of objects and materials despite complexities in the way images are structured by the interaction of light with surface properties (3D shape, albedo, and gloss or specularity). Although the perception of gloss (and lightness) has been argued to depend on image statistics (e.g., sub-band skew), studies have shown that perceived gloss depends critically on the structure of luminance variations in images. Here, we found that separately adapting observers to either positive or negative skew generated declines in perceived gloss, contrary to the predictions of theories involving image statistics. We also found similar declines in perceived gloss following adaptation to contours geometrically correlated with sharp specular edges. We further found this aftereffect was stronger when contour adaptors were aligned with specular edges compared with adaptation to the same contours rotated by 90. These findings support the view that the perception of gloss depends critically on the visual system's ability to encode specular edge structure and not image skew.

Highlight shapes and perception of gloss for real and photographed objects

Journal of Vision, 2016

Gloss perception strongly depends on the threedimensional shape and the illumination of the object under consideration. In this study we investigated the influence of the spatial structure of the illumination on gloss perception. A diffuse light box in combination with differently shaped masks was used to produce a set of six simple and complex highlight shapes. The geometry of the simple highlight shapes was inspired by conventional artistic practice (e.g., ring flash for photography, window shape for painting and disk or square for cartoons). In the box we placed spherical stimuli that were painted in six degrees of glossiness. This resulted in a stimulus set of six highlight shapes and six gloss levels, a total of 36 stimuli. We performed three experiments of which two took place using digital photographs on a computer monitor and one with the real spheres in the light box. The observers had to perform a comparison task in which they chose which of two stimuli was glossiest and a rating task in which they rated the glossiness. The results show that, perhaps surprisingly, more complex highlight shapes were perceived to produce a less glossy appearance than simple highlight shapes such as a disk or square. These findings were confirmed for both viewing conditions, on a computer display and in a real setting. The results show that variations in the spatial structure of ''rather simple'' illumination of the ''extended source'' type highlight influences perceived glossiness.

Glossiness perception can be mediated independently of cortical processing of colour or texture

Cortex, 2012

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Image Contrast Measure as a Gloss Material Descriptor

Lecture Notes in Computer Science, 2017

Bidirectional reflectance distribution function provides a physical description of material appearance. In particular, it helps to describe the gloss. We suggest that, at least, one attribute of gloss: Contrast gloss (luster), may be described directly from an image by using local image contrast measurement. In this article, we investigate the relation between image contrast measures, gloss perception and bidirectional reflectance distribution function based on the Ward's α model parameter. Although more investigation is required to provide stronger conclusions, it seems that image related contrast measures may provide an indication of gloss perception.

Human cortical areas involved in perception of surface glossiness

NeuroImage, 2014

Glossiness is the visual appearance of an object's surface as defined by its surface reflectance properties. Despite its ecological importance, little is known about the neural substrates underlying its perception. In this study, we performed the first human neuroimaging experiments that directly investigated where the processing of glossiness resides in the visual cortex. First, we investigated the cortical regions that were more activated by observing high glossiness compared with low glossiness, where the effects of simple luminance and luminance contrast were dissociated by controlling the illumination conditions (Experiment 1). As cortical regions that may be related to the processing of glossiness, V2, V3, hV4, VO-1, VO-2, collateral sulcus (CoS), LO-1, and V3A/B were identified, which also showed significant correlation with the perceived level of glossiness. This result is consistent with the recent monkey studies that identified selective neural response to glossiness in the ventral visual pathway, except for V3A/B in the dorsal visual pathway, whose involvement in the processing of glossiness could be specific to the human visual system. Second, we investigated the cortical regions that were modulated by selective attention to glossiness (Experiment 2). The visual areas that showed higher activation to attention to glossiness than that to either form or orientation were identified as right hV4, right VO-2, and right V3A/B, which were commonly identified in Experiment 1. The results indicate that these commonly identified visual areas in the human visual cortex may play important roles in glossiness perception.

Quantification of gloss perception as a function of stimulus duration

2007

The mechanism and temporal characteristics of gloss perception are not entirely clear. In addition, the formulation for predicting gloss perception from photometric values has not been established. In the present study, we conducted an experiment to measure several temporal characteristics of gloss perception in order to clarify the mechanism. All stimuli were rendered as computer graphics with Phong and Lambert models to provide gloss perception to human observers. We measured perceptual glossiness with a magnitude estimation method and perceptual diffuse/specular reflectance of test stimuli with a matching method under several stimulus conditions, such as reflectance coefficients and stimulus duration. The results showed that the perceptual specular component and perceptual glossiness increase with decreasing stimulus duration. Finally, we proposed a formulation to predict perceptual glossiness as a function of stimulus duration.

Contextual effects in human gloss perception

Electronic Imaging, 2018

The well-known simultaneous contrast effect describes how surrounding surfaces influence lightness perception. Similar contextual effects are ubiquitous in the lightness literature. Contextual effects in gloss perception however, have not yet been studied intensively. Here, we describe two distinct studies that investigate the role of spatial interactions between different glossy materials. In a first study we produced real surfaces that contain two different materials and compared perceived gloss in two conditions: in isolation and in context with a second material. Our results provide strong evidence that the context largely influences perceived gloss. Gloss ratings of identical materials differed depending on the presentation mode. In a second study we wished to quantify the strength of these contextual effects using Maximum likelihood conjoint measurement. We used glossy versions of the simultaneous contrast display and again found strong influences of albedo and gloss of the surroundings on perceived gloss and lightness. Both studies hint towards a profound influence of the context on perceived gloss. Investigating spatial interactions between materials within a scene has largely been studied in the lightness literature but only received moderate attention in the gloss literature. Our results provide confirmatory evidence that perceived gloss is shaped by other materials in the scene.

How Mesoscale and Microscale Roughness Affect Perceived Gloss

2012

We have studied how perceived gloss varies with the change of both mesoscale and microscale roughness on 3D surface textures. The mesoscale roughness was changed by varying the roll-off factor (β) of 1/f β fractal noise surfaces. The microscale roughness was changed by varying the microscale roughness parameter α in the microfacet reflection model. An HDR real-world environment map was used to provide complex illumination and a physicallybased path tracer was used for rendering the stimuli. Each simulated surface was rotated about its vertical axis to generate an animated stimulus. Eight observers took part in a 2AFC experiment, and the results were tested against conjoint measurement models. We found that the perceived gloss changes non-monotonically with β (an asymmetric bell curve), and monotonically with α. Although both β and α significantly affect perceived gloss, the additive model is inadequate to describe their interactive and nonlinear influence, which is at variance with previous results .

The Role of Subsurface Scattering in Glossiness Perception

ACM Transactions on Applied Perception (TAP), 2021

This study investigates the potential impact of subsurface light transport on gloss perception for the purposes of broadening our understanding of visual appearance in computer graphics applications. Gloss is an important attribute for characterizing material appearance. We hypothesize that subsurface scattering of light impacts the glossiness perception. However, gloss has been traditionally studied as a surface-related quality and the findings in the state-of-the-art are usually based on fully opaque materials, although the visual cues of glossiness can be impacted by light transmission as well. To address this gap and to test our hypothesis, we conducted psychophysical experiments and found that subjects are able to tell the difference in terms of gloss between stimuli that differ in subsurface light transport but have identical surface qualities and object shape. This gives us a clear indication that subsurface light transport contributes to a glossy appearance. Furthermore, we ...