Dr Andrew Schofield BEng PhD

Dr Andrew Schofield

School of Psychology
Senior Lecturer
Deputy Director of Education (Quality Assurance), College of Life and Environmental Sciences

Contact details

Address
School of Psychology
University of Birmingham
Edgbaston
Birmingham
B15 2TT
UK

Andrew Schofield's primary research is on functional aspects of the visual perception with an emphasis on textures, surfaces and shape. He also has interests in the effects of ageing on visual perception and the role of cortical hyper-excitability in abnormal visual functioning. He also builds computational models of human vision and designs computer vision algorithms.

Qualifications

BEng, PGDip, PhD

Biography

With a first degree in Electronics, a PhD in Communication and Neuroscience and a PG-Diploma in Psychology Andrew Schofield is a multidisciplinary thinker whose work on visual perception crosses the boundaries between Psychology and Computer Science. After receiving his PhD Andrew completed a Research Fellowship in image processing at Brunel and then worked for a year in the Civil Service before returning to academia as a Research Fellow in Psychology at Birmingham in 1996. He was appointed Lecturer in 1999 and Senior Lecturer in 2006. He is a past-chair of the Applied Vision Association and currently leads the EPSRC Network Visual Image Interpretation in Humans and Machines.

Teaching

Andrew Schofield is a tutor and project supervisor for the School's BSc programme, as well as a project and placement supervisor at MSc/MA level. He also teaches on the following topics: 

  • Visual perception and illusions
  • Minds, brains and models

Postgraduate supervision

  • Alice Cruickshank (graduated)
  • Peng Sun (graduated)
  • Dicle Dovencioglu (graduated)
  • Giacommo Mazzilli (graduated)
  • Austyn Tempesta
  • Krishnakumar Perumal

Research

My primary research is at the interface between Psychology and Computer Science; understanding human vision and designing new computer vision algorithms. I believe that our understanding of human visual perception can best be enhanced by constructing functional and biologically plausible models that replicate human performance. Unless such models are implemented in software we cannot be sure that they offer correct simulations. Further, if our knowledge of the visual system is to have impact – in the engineering domain – we must seek to solve engineering problems using the techniques developed. 

Most recently my EPSRC work on texture perception (second-order vision) led to a new model for how humans separate changes in lighting from materials changes within a scene (layer decomposition). This led to another EPSRC project in which we designed a computer vision system based on the human model to perform the same task. This research strand best exemplifies my desire to transfer our understanding of human vision to computer vision applications. The need for such knowledge transfer has been highlighted as part of the EPSRC Shaping Capability exercise. I am also interested in how humans extract the shape of a surface from the pattern of illumination across it (shape-from-shading), how such judgments are affected by illumination and more importantly by our often flawed assessment of the dominant lighting direction in scenes. 

I have recently become interested in dysfunctional visual perception as can occur with ageing and in developmental conditions such as dyslexia and autism. The elderly and those with autism both show deficits for processing the kinds of visual texture that aid the discrimination of lighting and martial changes. This observation has led to a pilot study (with Mark Hollands and Harriet Allen) to look at the functional deficits that arise from this neural loss in an older adult population. So far we have found that older adults are less able to detect material changes among lighting changes than young controls. We have also found that young controls use such cues subconsciously to direct foot trajectories when climbing steps whereas older adults fail to make the foot height adjustments. 

Via joint PhD supervision I am currently pursuing and interest in reading specifically the effect of Visual Stress / Cortical Hyper-excitability on reading speed. This project will involve EEG time-frequency and ERP analysis and will hopefully lead to a computational mode of how spreading cortical hyper-excitability might produce hallucinatory perceptions including colours, blur and illusory motion that disrupt reading. 

Collaborators / co-workers
Mark Georgeson, Harriet Allen, Mark Hollands, Xiaoyue Jiang, Jeremy Wyatt, Frederick Kingdom, Tim Ledgeway,.

Links relating to my research

Other activities

  • Past Chair of the Applied Vision Association
  • Lead for EPSRC Network on Visual Image Interpretation in Humans and Machines
  • Deputy Director of Education (QA) College of Life and Environmental Sciences

Publications

Schofield, A.J., Curzon-Jones, B. & Hollands, M.A. (2017) Reduced sensitivity for visual textures affects judgments of shape-from-shading and step-climbing behaviour in older adults, Experimental Brain Research, 235: 573-583. doi:10.1007/s00221-016-4816-0

Georgeson, MA & Schofield, AJ 2016, 'Binocular functional architecture for detection of contrast-modulated gratings' Vision Research, vol 128, pp. 68-82. DOI: 10.1016/j.visres.2016.09.005

Schofield A.J., & Kingdom, F.A.A., (2014) Texture variations suppress suprathreshold brightness and colour variations. PLoS One, 9,12 e114803 (DOI: 10.1371/journal.pone.0114803)

Mazzilli, G., & Schofield, A.J., (2013) A cue-free methods to probe human shape from shading. Perception, 42, 9, 932-940.

Dovencioglu, D.N., Ban H., Schofield A.J., Welchman, A.E. (2013) Perceptual integration for qualitatively different 3D cues in the human brain, Journal of Cognitive Neuroscience, 25, 9, 1527-1541. 9

Observations on Shape-from-Shading in Humans
Schofield, A., Sun, P. & Mazzilli, G. 2013 Shape Perception in Human and Computer Vision: An Interdisciplinary Perspective. Dickinson, S. & Pizlo, Z. (eds.). London: Springer, p. 119 132 p. (Advances in Computer Vision and Pattern Recognition)

Dovencioglu, D.N., Welchman, A.E., Schofield A.J., (2013) Perceptual learning of second order cues for layer decomposition. Vision Research, 77, 1-9

Sun P., & Schofield A.J. (2012) Two operational modes in the perception of shape-from-shading revealed by the effects of edge information in slant settings. Journal of Vision, 12 (1): 12. doi:10.1167/12.1.12

Schofield, A.J., Rock, P.B., & Georgeson, M.A. (2011) Sun and sky: Does human vision assume a mixture of point and diffuse illumination when interpreting shape-from-shading? Vision Research, 51, (21-22), 2317-2330.

Jiang X., Schofield A.J., & Wyatt J.L. (2011), Shadow Detection based on Colour Segmentation and Estimated Illumination. Proceeding of the 22nd British Machine Vision Conference 2011 (BMVC2011), Jesse Hoey, Stephen McKenna and Emanuele Trucco, editors, BMVA Press, September 2011. doi:10.5244/C.25

Sun, P., Schofield A.J., (2011) The efficacy of local luminance amplitude in disambiguating the origin of luminance signals depends on carrier frequency: Further evidence for the active role of second-order vision in layer decomposition, Vision Research, 51, 496–507

Jiang, X., Schofield, A.J., Wyatt, J.L., (2010) Correlation-Based Intrinsic Image Extraction from a Single Image, in K. Daniilidis, P. Maragos, N. Paragios (Eds.) ECCV 2010, Part IV, LNCS 6314, pp. 58–71, Springer-Verlag, Berlin.

Schofield A.J., Rock, P.B., Sun P., Jiang, X, Georgeson M.A., (2010) What is second-order vision for? Discriminating illumination versus material changes, Journal of Vision 10(9): 2; doi:10.1167/10.9.2.

Rothtein, P., Schofield, A, Funes, M.J., Humphreys, G.W., (2010) Effects of spatial frequency bands on perceptual decision: It is not the stimuli but the comparison. Journal of Vision 10(10): 25; doi:10.1167/10.10.25

Georgeson, M.A., Yates, T.A., & Schofield, A.J., (2009). Depth propagation and surface construction in 3-D vision. Vision Research, 49, 84-95.

Georgeson, M.A., Yates, T.A., & Schofield A.J., (2008). Discriminating depth in corrugated stereo surfaces: Facilitation by a pedestal is explained by removal of uncertainty. Vision Research, 48, 2321-2328.

Riddoch, M. J., Humphreys, G., Akhtar, N., Allen, H., Bracewell, R.M., Schofield, A. (2008). A tale of two agnosias: Distinctions between form and integrative agnosia, Cognitive Neuropsychology, 25, 56-92.

Schofield, A. J., Ledgeway, T., & Hutchinson, C. V. (2007). Asymmetric transfer of the dynamic motion aftereffect between first- and second-order cues and among different second-order cues. Journal of Vision, 7(8):1, 1-12 

Schofield, A.J., Hesse, G., Rock, P.B., Georgeson, M.A. (2006) Local luminance amplitude modulates the interpretation of shape-from-shading in textured surfaces. Vision Research, 46, 3462-3482

Schofield, A.J., Bishop, N.J., and Allan, J. (2006) Oscillatory motion induces change blindness. Acta Psychologica, 121,  249-274

Cruickshank, A.G, and Schofield A.J. (2005) Transfer of tilt after-effects between second-order cues. Spatial Vision, 18,  379-398

Schofield, A.J, and Yates, T.A. (2005) Interactions between orientation and contrast modulations suggest limited cross-cue linkage. Perception, 34, 769-792

Schofield, A.J, and Georgeson, M.A. (2003) Sensitivity to contrast modulations: the spatial frequency dependence of second-order vision, Vision Research 43, 243-259

Georgeson, M.A, and Schofield, A.J. (2002) Shading and Texture: separate information channels with a common adaptation mechanism?, Spatial Vision, 16, 59-76.

Schofield, A.J, and Georgeson, M.A. (2000) The temporal properties of first- and second-order vision, Vision Research, 40, 2475-2487

Schofield, A.J. (2000) What does second-order vision see in an image', Perception, 29, 1071-1086

Schofield, A.J. and Georgeson, M.A. (1999), Sensitivity to modulations of luminance and contrast in visual white noise: separate mechanisms with similar behaviour, Vision research, Vol 39, 2697-2716.

Expertise

Human visual perception – how we see things: optical illusions, 3D vision, the perception of texture

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