Alexander Muryy

Alexander Muryy
University of Reading · School of Psychology and Clinical Language Sciences

PhD

About

40
Publications
3,590
Reads
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296
Citations
Citations since 2016
17 Research Items
200 Citations
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2016201720182019202020212022010203040
2016201720182019202020212022010203040
2016201720182019202020212022010203040
Additional affiliations
June 2016 - present
University of Reading
Position
  • PostDoc Position
Description
  • Human navigation in 3D environments. We use virtual reality as a tool to study the representation of space in human mind.
December 2013 - June 2016
University of Southampton
Position
  • PostDoc Position
Description
  • Natural scenes statistics. We are creating a database of aligned measurements (range, luminance, stereo) in natural scenes. The statistical analysis of these measurements will help us understand priors in human visual perception.
September 2010 - December 2013
University of Birmingham
Position
  • PostDoc Position
Description
  • Project: specular stereo. Computations and modelling of stereo disparity fields generated by 3D mirror objects, psycho-physical experiments on depth perception and material perception.

Publications

Publications (40)
Article
Full-text available
Recovering 3D scenes from 2D images is an under-constrained task; optimal estimation depends upon knowledge of the underlying scene statistics. Here we introduce the Southampton-York Natural Scenes dataset (SYNS: https://syns.soton.ac.uk), which provides comprehensive scene statistics useful for understanding biological vision and for improving mac...
Article
Full-text available
Visually identifying glossy surfaces can be crucial for survival (e.g. ice patches on a road), yet estimating gloss is computationally challenging for both human and machine vision. Here, we demonstrate that human gloss perception exploits some surprisingly simple binocular fusion signals, which are likely available early in the visual cortex. In p...
Article
Full-text available
Because specular reflection is view-dependent, shiny surfaces behave radically differently from matte, textured surfaces when viewed with two eyes. As a result, specular reflections pose substantial problems for binocular stereopsis. Here we use a combination of computer graphics and geometrical analysis to characterize the key respects in which sp...
Article
Full-text available
Binocular stereopsis is a powerful visual depth cue. To exploit it, the brain matches features from the two eyes' views and measures their interocular disparity. This works well for matte surfaces because disparities indicate true surface locations. However, specular (glossy) surfaces are problematic because highlights and reflections are displaced...
Article
Full-text available
We present a method for measurement and reconstruction of light fields in finite spaces. Using a custom-made device called a plenopter, we can measure spatially and directionally varying radiance distribution functions from a real-world scene up to their second-order spherical harmonics approximations. Interpolating between measurement points, we c...
Article
Full-text available
The way people choose routes through unfamiliar environments provides clues about the underlying representation they use. One way to test the nature of observers’ representation is to manipulate the structure of the scene as they move through it and measure which aspects of performance are significantly affected and which are not. We recorded the r...
Article
Full-text available
Neuroscientists postulate 3D representations in the brain in a variety of different coordinate frames (e.g. ‘head-centred’, ‘hand-centred’ and ‘world-based’). Recent advances in reinforcement learning demonstrate a quite different approach that may provide a more promising model for biological representations underlying spatial perception and navig...
Preprint
Full-text available
The way people choose routes through unfamiliar environments provides clues about the underlying representation they use. One way to test the nature of observers' representation is to manipulate the structure of the scene as they move through it and measure which aspects of performance are significantly affected and which are not. We recorded the r...
Preprint
Full-text available
Neuroscientists postulate 3D representations in the brain in a variety of different coordinate frames (e.g. 'head-centred', 'hand-centred' and 'world-based'). Recent advances in reinforcement learning demonstrate a quite different approach that may provide a more promising model for biological representations underlying spatial perception and navig...
Article
Full-text available
There have been suggestions that human navigation may depend on representations that have no metric, Euclidean interpretation but that hypothesis remains contentious. An alternative is that observers build a consistent 3D representation of space. Using immersive virtual reality, we measured the ability of observers to point to targets in mazes that...
Article
Full-text available
Scientific Reports 6 : Article number: 35805 10.1038/srep35805 ; published online: 26 October 2016 ; updated: 13 March 2017 A glitch in the authors’ reference-management software led to extensive errors in the reference list and in-text citations.
Article
The Southampton-York Natural Scenes (SYNS) dataset consists of LiDAR range and image data captured from a variety of natural and built environments. One of our goals is to use the dataset to relate the ecological statistics of 3D surfaces to human perception of surface attitude. A local planar fit at a 3D point in the dataset can be estimated from...
Article
Full-text available
The visual impression of an object's surface reflectance ('gloss') relies on a range of visual cues, both monocular and binocular. While previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here we used human functiona...
Conference Paper
Humans are adept at estimating 3D scene geometry from a stereo image pair, or even from a single image. Computer vision algorithms are less good. Gaining traction on this problem requires a dataset that contains good quality images and ground truth data, and represents the complex and diverse scenes that we encounter. To this end we have developed...
Article
The University of Southampton (UK) and York University (Canada) have collaborated to build the Southampton-York Natural Scenes (SYNS) public dataset. Our goal is to provide a resource that can be used to relate properties of the human visual system to the statistics of natural scenes. At each scene a 3D point cloud was captured with a Leica P20 LiD...
Article
We are interested in the relationship between human vision and the environment in which it operates. To this end, the University of Southampton (UK) and York University (Canada) have collaborated to build the Southampton-York Natural Scenes (SYNS) public dataset. To represent the diverse environments that humans experience, we sampled scenes from 1...
Article
Underestimation of slant is a well-known bias in human surface attitude perception. Does this frontoparallel bias have a rational basis? If we consider a single tilt axis, and assume a world in which surfaces are uniformly distributed across slant, then a frontoparallel bias is predicted: surfaces with smaller slants project to larger regions of th...
Conference Paper
Surface gloss information conveyed by image cues (i.e., highlights) has been shown to be processed in ventral and dorsal areas. In this study we used fMRI to distinguish the brain areas that selectively process 2D and 3D cues about surface gloss. We performed one experiment using 2D images of random objects with glossy surfaces where diffuse highli...
Conference Paper
Specular (shiny) surfaces appear more realistic if highlights have binocular disparities that are physically correct. But which specific binocular cues does the visual system use to identify specular reflections? We computationally analyzed the disparity fields generated by irregularly shaped matte and specular objects and found several differences...
Poster
Full-text available
Specular (shiny) surfaces appear more realistic if highlights have binocular disparities that are physically correct. But which specific binocular cues does the visual system use to identify specular reflections? We computationally analyzed the disparity fields generated by irregularly shaped matte and specular objects and found several differences...
Article
The disparity fields created by matte surfaces match the surface's true depth profile. However, for specular surfaces the disparities are shifted away from the surface, tracing out virtual ('adanaclastic') surfaces in depth. Previous studies (Blake & Bülthoff, 1990, Nature, 343, 165; Wendt et al, 2008, doi:10.1167/8.1.14) showed that surfaces appea...
Conference Paper
When viewing a specular object, such as a highly polished kettle, the retinal image consists of a distorted version of the surrounding environment. If viewing binocularly, a given environmental feature is generally reflected to the left and right eyes from different surface locations, leading to a pattern of disparities that does not coincide with...
Article
Full-text available
Light fields [J. Math. Phys. 18, 51 (1936); The Photic Field (MIT, 1981)] of natural scenes are highly complex and vary within a scene from point to point. However, in many applications complex lighting can be successfully replaced by its low-order approximation [J. Opt. Soc. Am. A 18, 2448 (2001); Appl. Opt. 46, 7308 (2007)]. The purpose of this r...
Article
We present a method for measurement and reconstruction of second order approximations of light fields in closed spaces. We visualized their structure using light tubes and rendered objects at several points along a tube.
Article
Full-text available
The structure of light fields of natural scenes is highly complex due to high frequencies in the radiance distribution function. However it is the low-order properties of light that determine the appearance of common matte materials. We describe the local light field in terms of spherical harmonics and analyze the qualitative properties and physica...
Conference Paper
Light fields [Gershun 1939] of natural scenes are highly complex and vary within a scene from point to point. However, in many applications complex lighting can be successfully replaced by its low order approximation [Ramamoorthi and Hanrahan 2001]. The purpose of this research was to investigate the spatial behavior of light fields in natural scen...
Article
Regularities of the reflection of optical rays upon reflection from a plane-parallel crystalline plate are established. It is shown that in general four rays are formed in the direction of the reflected rays. On a screen, these rays create points lying at the vertices of a parallelogram. © 2005 Optical Society of America
Article
This paper shows that there are directions in which the ordinary and extraordinary rays coincide in a plane-parallel plate fabricated from an optical uniaxial crystal. Such directions of coincidence are important in creating optical phase plates or light filters with oblique incidence of rays of small cross section onto a plate when holographic gra...
Article
This paper shows that large angles of separation of rays with orthogonal polarizations can be achieved by deflecting the extraordinary ray to a side face of a crystal. When the rays are normally incident on the prism, the separation angle equals 40° for HgS, 18° for TeO2, and 10° for LiNbO3. As the angle of incidence of the rays on the prism varies...
Article
The aim of our studies is to understand the physical structure and human perception of natural light fields. The light field depends on the primary illumination, the scattering properties of the environment and the scene geometry. We present our newly developed methods to describe, measure and visualize visually complete descriptions of the light f...
Article
Full-text available
This thesis focuses on the properties of light fields with respect to object appearance. More specifically, our interest was mainly directed to the structure and spatial variation of light fields in natural scenes. We approached the structure of light fields by means of spherical harmonics which allows one to divide the complicated spherical functi...

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