September 2017
Volume 17, Issue 10
Open Access
Vision Sciences Society Annual Meeting Abstract  |   August 2017
Manipulations of local, but not global, luminance gradients affect judgements of depth magnitude
Author Affiliations
  • Paul Hibbard
    Department of Psychology, University of Essex
  • Ross Goutcher
    Psychology, University of Stirling
  • Naveed Khan
    Department of Psychology, University of Essex
  • Rebecca Hornsey
    Department of Psychology, University of Essex
Journal of Vision August 2017, Vol.17, 1045. doi:
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      Paul Hibbard, Ross Goutcher, Naveed Khan, Rebecca Hornsey; Manipulations of local, but not global, luminance gradients affect judgements of depth magnitude. Journal of Vision 2017;17(10):1045. doi:

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      © ARVO (1962-2015); The Authors (2016-present)

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In local image neighbourhoods, points in the scene that are closer to the observer tend to be brighter (Potetz and Lee, 2003). When images are manipulated to exaggerate or reduce this, the quality of the resulting 3D experience can be enhanced or diminished (Cooper and Norcia, 2014). We assessed whether this affected the magnitude of depth perceived and whether this was a local or a global effect. We created scenes using a collection of scanned 3D objects, rendered stereoscopically, and manipulated the luminance of individual pixels to enhance or reduce the relationship between distance and luminance, either globally or locally. In the global enhancement condition, the mean luminance of each object was increased or decreased depending on whether it was nearer or further away than the mean object distance, in proportion to its distance from the mean. In the global reduction condition, the luminance of nearer objects was reduced, and that of further objects increased. In the local conditions, similar manipulations were made to the luminance of individual pixels on each object, depending on their position in depth relative to other pixels belonging to that object. On each trial, two dots were overlaid on the scene, either on different objects (global condition) or on the same object (local condition). The observer's task was to set the length of an onscreen ruler to match the 3D distance between the two points. The luminance manipulation had no effect in the global condition. In the local condition, greater depth was perceived in the enhanced condition, for both stereoscopic and non-stereoscopic viewing. These results show that the manipulation of the statistical relationship between distance and luminance influences perceived depth. Consistent with the statistics of natural scenes, this effect is local, and did not affect perceived depth in the global condition.

Meeting abstract presented at VSS 2017


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