The role of texture in shape from shading: are humans biased towards seeing relief textures?

Andrew J. Schofield, Gillian Hesse, Mark A. Georgeson, P.B. Rock

Research output: Contribution to conferencePaper

Abstract

When a textured surface is modulated in depth and illuminated, the level of illumination varies across the surface, producing coarse-scale luminance modulations (LM) and amplitude modulation (AM) of the fine-scale texture. If the surface has an albedo texture (reflectance variation) then the LM and AM components are always in-phase, but if the surface has a relief texture the phase relation between LM and AM varies with the direction and nature of the illuminant. We showed observers sinusoidal luminance and amplitude modulations of a binary noise texture, in various phase relationships, in a paired-comparisons design. In the first experiment, the combinations under test were presented in different temporal intervals. Observers indicated which interval contained the more depthy stimulus. LM and AM in-phase were seen as more depthy than LM alone which was in turn more depthy than LM and AM in anti-phase, but the differences were weak. In the second experiment the combinations under test were presented in a single interval on opposite obliques of a plaid pattern. Observers were asked to indicate the more depthy oblique. Observers produced the same depth rankings as before, but now the effects were more robust and significant. Intermediate LM/AM phase relationships were also tested: phase differences less than 90 deg were seen as more depthy than LM-only, while those greater than 90 deg were seen as less depthy. We conjecture that the visual system construes phase offsets between LM and AM as indicating relief texture and thus perceives these combinations as depthy even when their phase relationship is other than zero. However, when different LM/AM pairs are combined in a plaid, the signals on the obliques are unlikely to indicate corrugations of the same texture, and in this case the out-of-phase pairing is seen as flat. [Supported by the Engineering and Physical Sciences Research Council (EPSRC)].
Original languageEnglish
Publication statusPublished - 2005
EventTwenty-eighth European Conference on Visual Perception - A Corunña, Spain
Duration: 22 Aug 200526 Aug 2005

Conference

ConferenceTwenty-eighth European Conference on Visual Perception
CountrySpain
CityA Corunña
Period22/08/0526/08/05

Fingerprint

shading
relief
texture
physical science
ranking
albedo
reflectance
experiment
engineering

Bibliographical note

Abstract published in ECVP 2005 Abstract Supplement, Perception, 34 (Suppl. S), p.56, ISSN: 0001-4966.

Keywords

  • textured surface
  • depth modulation
  • illumination
  • coarse-scale luminance modulations
  • amplitude modulation

Cite this

Schofield, A. J., Hesse, G., Georgeson, M. A., & Rock, P. B. (2005). The role of texture in shape from shading: are humans biased towards seeing relief textures?. Paper presented at Twenty-eighth European Conference on Visual Perception, A Corunña, Spain.
Schofield, Andrew J. ; Hesse, Gillian ; Georgeson, Mark A. ; Rock, P.B. / The role of texture in shape from shading: are humans biased towards seeing relief textures?. Paper presented at Twenty-eighth European Conference on Visual Perception, A Corunña, Spain.
@conference{9207af0e9c5b4336a9bb52d2eccd9ab8,
title = "The role of texture in shape from shading: are humans biased towards seeing relief textures?",
abstract = "When a textured surface is modulated in depth and illuminated, the level of illumination varies across the surface, producing coarse-scale luminance modulations (LM) and amplitude modulation (AM) of the fine-scale texture. If the surface has an albedo texture (reflectance variation) then the LM and AM components are always in-phase, but if the surface has a relief texture the phase relation between LM and AM varies with the direction and nature of the illuminant. We showed observers sinusoidal luminance and amplitude modulations of a binary noise texture, in various phase relationships, in a paired-comparisons design. In the first experiment, the combinations under test were presented in different temporal intervals. Observers indicated which interval contained the more depthy stimulus. LM and AM in-phase were seen as more depthy than LM alone which was in turn more depthy than LM and AM in anti-phase, but the differences were weak. In the second experiment the combinations under test were presented in a single interval on opposite obliques of a plaid pattern. Observers were asked to indicate the more depthy oblique. Observers produced the same depth rankings as before, but now the effects were more robust and significant. Intermediate LM/AM phase relationships were also tested: phase differences less than 90 deg were seen as more depthy than LM-only, while those greater than 90 deg were seen as less depthy. We conjecture that the visual system construes phase offsets between LM and AM as indicating relief texture and thus perceives these combinations as depthy even when their phase relationship is other than zero. However, when different LM/AM pairs are combined in a plaid, the signals on the obliques are unlikely to indicate corrugations of the same texture, and in this case the out-of-phase pairing is seen as flat. [Supported by the Engineering and Physical Sciences Research Council (EPSRC)].",
keywords = "textured surface, depth modulation, illumination, coarse-scale luminance modulations, amplitude modulation",
author = "Schofield, {Andrew J.} and Gillian Hesse and Georgeson, {Mark A.} and P.B. Rock",
note = "Abstract published in ECVP 2005 Abstract Supplement, Perception, 34 (Suppl. S), p.56, ISSN: 0001-4966.; Twenty-eighth European Conference on Visual Perception ; Conference date: 22-08-2005 Through 26-08-2005",
year = "2005",
language = "English",

}

Schofield, AJ, Hesse, G, Georgeson, MA & Rock, PB 2005, 'The role of texture in shape from shading: are humans biased towards seeing relief textures?' Paper presented at Twenty-eighth European Conference on Visual Perception, A Corunña, Spain, 22/08/05 - 26/08/05, .

The role of texture in shape from shading: are humans biased towards seeing relief textures? / Schofield, Andrew J.; Hesse, Gillian; Georgeson, Mark A.; Rock, P.B.

2005. Paper presented at Twenty-eighth European Conference on Visual Perception, A Corunña, Spain.

Research output: Contribution to conferencePaper

TY - CONF

T1 - The role of texture in shape from shading: are humans biased towards seeing relief textures?

AU - Schofield, Andrew J.

AU - Hesse, Gillian

AU - Georgeson, Mark A.

AU - Rock, P.B.

N1 - Abstract published in ECVP 2005 Abstract Supplement, Perception, 34 (Suppl. S), p.56, ISSN: 0001-4966.

PY - 2005

Y1 - 2005

N2 - When a textured surface is modulated in depth and illuminated, the level of illumination varies across the surface, producing coarse-scale luminance modulations (LM) and amplitude modulation (AM) of the fine-scale texture. If the surface has an albedo texture (reflectance variation) then the LM and AM components are always in-phase, but if the surface has a relief texture the phase relation between LM and AM varies with the direction and nature of the illuminant. We showed observers sinusoidal luminance and amplitude modulations of a binary noise texture, in various phase relationships, in a paired-comparisons design. In the first experiment, the combinations under test were presented in different temporal intervals. Observers indicated which interval contained the more depthy stimulus. LM and AM in-phase were seen as more depthy than LM alone which was in turn more depthy than LM and AM in anti-phase, but the differences were weak. In the second experiment the combinations under test were presented in a single interval on opposite obliques of a plaid pattern. Observers were asked to indicate the more depthy oblique. Observers produced the same depth rankings as before, but now the effects were more robust and significant. Intermediate LM/AM phase relationships were also tested: phase differences less than 90 deg were seen as more depthy than LM-only, while those greater than 90 deg were seen as less depthy. We conjecture that the visual system construes phase offsets between LM and AM as indicating relief texture and thus perceives these combinations as depthy even when their phase relationship is other than zero. However, when different LM/AM pairs are combined in a plaid, the signals on the obliques are unlikely to indicate corrugations of the same texture, and in this case the out-of-phase pairing is seen as flat. [Supported by the Engineering and Physical Sciences Research Council (EPSRC)].

AB - When a textured surface is modulated in depth and illuminated, the level of illumination varies across the surface, producing coarse-scale luminance modulations (LM) and amplitude modulation (AM) of the fine-scale texture. If the surface has an albedo texture (reflectance variation) then the LM and AM components are always in-phase, but if the surface has a relief texture the phase relation between LM and AM varies with the direction and nature of the illuminant. We showed observers sinusoidal luminance and amplitude modulations of a binary noise texture, in various phase relationships, in a paired-comparisons design. In the first experiment, the combinations under test were presented in different temporal intervals. Observers indicated which interval contained the more depthy stimulus. LM and AM in-phase were seen as more depthy than LM alone which was in turn more depthy than LM and AM in anti-phase, but the differences were weak. In the second experiment the combinations under test were presented in a single interval on opposite obliques of a plaid pattern. Observers were asked to indicate the more depthy oblique. Observers produced the same depth rankings as before, but now the effects were more robust and significant. Intermediate LM/AM phase relationships were also tested: phase differences less than 90 deg were seen as more depthy than LM-only, while those greater than 90 deg were seen as less depthy. We conjecture that the visual system construes phase offsets between LM and AM as indicating relief texture and thus perceives these combinations as depthy even when their phase relationship is other than zero. However, when different LM/AM pairs are combined in a plaid, the signals on the obliques are unlikely to indicate corrugations of the same texture, and in this case the out-of-phase pairing is seen as flat. [Supported by the Engineering and Physical Sciences Research Council (EPSRC)].

KW - textured surface

KW - depth modulation

KW - illumination

KW - coarse-scale luminance modulations

KW - amplitude modulation

M3 - Paper

ER -

Schofield AJ, Hesse G, Georgeson MA, Rock PB. The role of texture in shape from shading: are humans biased towards seeing relief textures?. 2005. Paper presented at Twenty-eighth European Conference on Visual Perception, A Corunña, Spain.