Verification of rendering quality from measured BTFs

Meseth, Jan; Müller, G.; Klein, Reinhard; Röder, Florian; Arnold, Michael

doi:10.1145/1140491.1140517

Cited by 18 publications

(12 citation statements)

References 34 publications

(35 reference statements)

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“…Meseth et al [23] evaluated the rendering quality obtained by using BTFs instead of simple 2D textures. A perception-based metric for single-level BTFs was derived in [24], in order to achieve higher compression rates.…”

Section: Previous Workmentioning

confidence: 99%

Effects of Approximate Filtering on the Appearance of Bidirectional Texture Functions

Jarabo

Dorsey

et al. 2014

IEEE Trans. Visual. Comput. Graphics

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Abstract-The BTF data structure was a breakthrough for appearance modeling in computer graphics. More research is needed though to make BTFs practical in rendering applications. We present the first systematic study of the effects of approximate filtering on the appearance of BTFs, by exploring the spatial, angular and temporal domains over a varied set of stimuli. We perform our initial experiments on simple geometry and lighting, and verify our observations on more complex settings. We consider multi-dimensional filtering versus conventional mipmapping, and find that multi-dimensional filtering produces superior results. We examine the trade off between under-and oversampling, and find that different filtering strategies can be applied in each domain, while maintaining visual equivalence with respect to a ground truth. For example, we find that preserving contrast is more important in static than dynamic images, indicating greater levels of spatial filtering are possible for animations. We find that filtering can be performed more aggressively in the angular domain than in the spatial. Additionally, we find that high-level visual descriptors of the BTF are linked to the perceptual performance of pre-filtered approximations. In turn, some of these high-level descriptors correlate with low level statistics of the BTF. We show six different practical applications of applying our findings to improving filtering, rendering and compression strategies.

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Section: Previous Workmentioning

confidence: 99%

Effects of Approximate Filtering on the Appearance of Bidirectional Texture Functions

Jarabo

Dorsey

et al. 2014

IEEE Trans. Visual. Comput. Graphics

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“…The first published psychophysical experiment using BTF data was conducted in [68], where the authors compared environmentally lit renderings of BTF [71], flat textures modulated by the Phong BRDF model, and photographs of a car interior scene. The image sets from these three techniques were the subject of a psychophysical study with the group of 22 participants.…”

Section: Modeling Quality Criteriamentioning

confidence: 99%

Bidirectional Texture Function Modeling: A State of the Art Survey

Filip

Haindl

2009

IEEE Trans. Pattern Anal. Mach. Intell.

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Abstract-An ever-growing number of real-world computer vision applications require classification, segmentation, retrieval, or realistic rendering of genuine materials. However, the appearance of real materials dramatically changes with illumination and viewing variations. Thus, the only reliable representation of material visual properties requires capturing of its reflectance in as wide range of light and camera position combinations as possible. This is a principle of the recent most advanced texture representation, the Bidirectional Texture Function (BTF). Multispectral BTF is a seven-dimensional function that depends on view and illumination directions as well as on planar texture coordinates. BTF is typically obtained by measurement of thousands of images covering many combinations of illumination and viewing angles. However, the large size of such measurements has prohibited their practical exploitation in any sensible application until recently. During the last few years, the first BTF measurement, compression, modeling, and rendering methods have emerged. In this paper, we categorize, critically survey, and psychophysically compare such approaches, which were published in this newly arising and important computer vision and graphics area.

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“…Several papers investigate influences of light position, material reflectance, view position, or surface shape [Fleming et al 2003], [Lawson et al 2003 [Meseth et al 2006] shows a study comparing performance of material photographs, BTF rendering, and flat textures modulated by BRDFs for the same illumination condition. Different BTF compression and modelling methods are perceptually compared in a recent survey [Filip and Haindl 2009].…”

Section: Prior Work 21 Psychovisual Analysismentioning

confidence: 99%

On uniform resampling and gaze analysis of bidirectional texture functions

Filip

Chantler²,

Haindl

2009

ACM Trans. Appl. Percept.

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The use of illumination and view dependent texture information is recently the best way to capture the appearance of real-world materials accurately. One example is the Bidirectional Texture Function. The main disadvantage of these data is their massive size. In this paper we employ perceptually-based methods to allow more efficient handling of these data. In the first step we analyse different uniform resampling by means of a psychophysical study with eleven subjects, comparing original data with rendering of a uniformly resampled version over the hemisphere of illumination and view dependent textural measurements. We have found that down-sampling in view and illumination azimuthal angles is less apparent than in elevation angles and that illumination directions can be down-sampled more than view directions without loss of visual accuracy. In the second step we analysed subjects gaze fixation during the experiment. The gaze analysis confirmed resuls from the experiment and revealed that subjects were fixating at locations aligned with direction of main gradient in rendered stimuli. As this gradient was mostly aligned with illumination gradient we conclude that subjects were observing materials mainly in direction of illumination gradient. Our results provide interesting insights in human perception of real materials and show promising consequences for development of more efficient compression and rendering algorithms using these kind of massive data.

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Verification of rendering quality from measured BTFs

Cited by 18 publications

References 34 publications

Effects of Approximate Filtering on the Appearance of Bidirectional Texture Functions

Effects of Approximate Filtering on the Appearance of Bidirectional Texture Functions

Bidirectional Texture Function Modeling: A State of the Art Survey

On uniform resampling and gaze analysis of bidirectional texture functions

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