.

Professor Mark Georgeson B.A., M.A., D.Phil.

Professor of Vision Sciences
School of Life and Health Sciences
Aston University
Birmingham B4 7ET
UK
email: M.A.Georgeson@aston.ac.uk

telephone: +44 (0) 121 204 4119

georgema-1.jpg
 

Research Theme

Vision, Hearing and Language

Research Centre

Centre for Research in Vision and Hearing(CRVH)

What I do

Experimental research & computational modelling of the mechanisms and processes of human visual perception, recently funded by project grants from the BBSRC and EPSRC (awarded jointly with Prof. Tim Meese)
Committee of the Applied Vision Association (AVA)
Editorial boards of Perception (1998- ) and Journal of Vision (2003- ).

Publications profile

Link to my Google Scholar profile

Downloads

Research Publications
Lab Notes & Software for Visual Psychophysics
News & Views
EPSRC grant S07261/01: Final report & manuscripts
Vision Science Demos :::  The motion aftereffect without motion [2011]

Brief CV

Mark Georgeson was educated at Preston Catholic College and Cambridge University where he studied Mathematics and Experimental Psychology (B.A. 1970). He worked on a variety of topics in spatial vision at Sussex University (D.Phil. 1975), then took up a lectureship at the University of Bristol (1976), moved on to Aston University (Birmingham, UK) as Reader in Vision Sciences (1991), then to Birmingham University as Professor of Psychology (1995). In 2001, he moved back to Aston as Professor of Vision Sciences. He has published about 80 papers on research topics in human vision, especially on spatio-temporal filtering operations and coding processes in spatial vision, motion perception and binocular vision. He is co-author (with Bruce & Green) of the widely used textbook Visual Perception: Physiology, Psychology & Ecology (1996, 2003). With Prof. Tim Meese, he is funded by research grants from UK research councils (EPSRC, BBSRC) to study spatial vision and binocular vision, and was previously funded by the Wolfson Foundation and the Wellcome Trust amongst others. He is active in the UK Applied Vision Association (Chairman 2005-8), was on the editorial board of  Vision Research (2000-2008) and Ophthalmic & Physiological Optics (2007-2010), and is currently active on the editorial boards of Perception (1998- ) and Journal of Vision (2003- ).

Visual Perception Text Book

Bruce V, Green P R, Georgeson M A (1996) Visual Perception: Physiology, Psychology and Ecology, 3rd edition. Hove & London: Psychology Press. pp.448.

Bruce V, Green P R, Georgeson M A (2003) Visual Perception: Physiology, Psychology and Ecology, 4th edition. Hove & London: Psychology Press.         http://www.psypress.com/visual-perception-9781841692388

Online Research Seminar (2008)

Four decades of spatial frequency channels: a scale-space view of spatial vision
An invited talk to the Craik Club, University of Cambridge, April 2008
http://www.crsltd.com/georgeson

Journal Papers & Book Chapters

Click on numbered hyperlinks for PDF download

Most recent

  • 84. Wallis SA, Baker DH, Meese TS, Georgeson MA (2013). The slope of the psychometric function and non-stationarity of thresholds in spatiotemporal contrast vision.  Vision Research 76, 1-10.

  • 83. Wallis SA, Georgeson MA (2012)  Mach bands and multiscale models of spatial vision: the role of 1st, 2nd and 3rd derivative operators in encoding bars and edges.  Journal of Vision, 12(13):18, 1-25.  http://www.journalofvision.org/12/13/18

     

  • 82. Baker DH, Wallis SA, Georgeson MA, Meese TS (2012).  The Effect of Interocular Phase Difference on Perceived Contrast.  PloS ONE, 7(4), 1-6.   Download PDF

  • 81. Baker DH, Wallis SA, Georgeson MA, Meese TS (2012). Nonlinearities in the binocular combination of luminance and contrast. Vision Research 56, 1-9.

  • 80.  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, 2317-2330.

  • 79. Elliott SL,  Georgeson MA, Webster, MA (2011). Response normalization and blur adaptation: data and multi-scale model. Journal of Vision 11(2):7, 1-18.  http://journalofvision.org/11/2/7/

  • 78. 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, 1-18.  http://journalofvision.org/10/9/2/

     

2000s

  • 77. Wallis S A, Georgeson M A  (2009). Mach Edges: local features predicted by 3rd derivative spatial filtering. Vision Research 49, 1886-1893.
  • 76. Georgeson M A, Yates T A, Schofield A J  (2009). Depth propagation and surface construction in 3-D vision. Vision Research 49, 84-95.
  • 75. 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.
  • 74. Georgeson MA, May KA, Freeman TCA, Hesse GS (2007) From filters to features: scale-space analysis of edge and blur coding in human vision. Journal of Vision, 7(13):7, 1-21. http://journalofvision.org/7/13/7/ + Supplementary figures
  • 73. May KA, Georgeson MA (2007b) Added luminance ramp alters perceived edge blur and contrast: a critical test for derivative-based models of edge coding. Vision Research, 47, 1721-1731.
  • 72. May KA, Georgeson MA (2007a) Blurred edges look faint, and faint edges look sharp: the effect of a gradient threshold in a multi-scale edge coding model. Vision Research, 47, 1705-1720.
  • 71. Baker DH, Meese TS & Georgeson MA (2007). Binocular interaction: Contrast matching and contrast discrimination are predicted by the same model. Spatial Vision 20(5), 397-413.
  • 70. Meese TS, Georgeson MA & Baker DH. (2006). Binocular contrast vision at and above threshold. Journal of Vision, 6(11), 1224-1243. http://journalofvision.org/6/11/7/
  • 69. Schofield AJ, Hesse G, Rock P & Georgeson MA (2006) Local luminance amplitude modulates the interpretation of shape-from-shading in textured surfaces. Vision Research, 46, 3462-3482.
  • 68. Georgeson M A , Meese T S (2006) Fixed or variable noise in contrast discrimination? The jury's still out… Vision Research, 46, 4294-4303.
  • 67. Meese, T. S. & Georgeson, M. A. (2005). Carving up the patchwise transform: Towards a filter combination model for spatial vision. Advances in Psychology Research, Volume 34, pp 51-88, Nova Science Publishers, New York.
  • 66. Georgeson M A, Lampard J, Georgeson J M (2005) Kits, colours and confusion: a pilot study of vision and football. Perception 34, 633-637.
    65. Hesse G S, Georgeson M A (2005) Edges and Bars: where do people see features in 1-D images? Vision Research. 45, 507-525.

  • 64. Cooper ACG, Humphreys GW, Hulleman J, Praamstra P & Georgeson MA (2004) Trans-cranial magnetic stimulation (TMS) to right parietal cortex modifies attentional blink. Experimental Brain Research 155, 24-29.

  • 63. Hammett S T, Georgeson M A, Barbieri-Hesse, GS (2003) Motion, flash and flicker: a unified spatio-temporal model of edge sharpening Perception 32, 1221-1232.

  • 62. Hammett S T, Georgeson M A, Bedingham S, Barbieri-Hesse, GS (2003) Motion sharpening and contrast: gain control precedes compressive non-linearity ? Vision Research 43, 1187-1199
  • 61. Schofield A J, Georgeson M A (2003). Sensitivity to contrast modulation: the spatial frequency dependence of second order vision. Vision Research. 43, 243 - 259.
  • 60. Georgeson M A, Schofield A J (2002). Shading & Texture: separate information channels with a common adaptation mechanism? Spatial Vision. 16, 59-76.
  • 59. Webster M A, Georgeson M A, Webster S M (2002) Neural adjustment to image blur. Nature Neuroscience, 5(9), 839-840.
  • 58. Georgeson M A, Hammett S T (2002) Seeing blur: ‘motion sharpening’ without motion. Proc Roy Soc B 269, 1429-1434.
  • 57. Schofield A J, Georgeson M A (2000). The temporal properties of first- and second-order vision. Vision Research. 40, 2475-2487.
  • 56. Georgeson M A, Scott-Samuel N E (2000) Spatial resolution and receptive field height of motion sensors in human vision. Vision Research. 40, 745-758.

1990s

  • 55. Scott-Samuel N E, Georgeson M A (1999) Feature matching and segmentation in motion perception. Proceedings of the Royal Society B 266, 2289-2294.
  • 54. Georgeson M A, Scott-Samuel N E (1999). Motion contrast: a new metric for direction discrimination. Vision Research. 39, 4393-4402.
  • 53. Georgeson M A, Meese T S (1999). Adaptive filtering in spatial vision: evidence from feature-marking in plaids. Perception 28, 687-702.
  • 52. Scott-Samuel N E, Georgeson M A (1999) Does early non-linearity account for second-order motion? Vision Research. 39, 2853-2865.
  • 51. Schofield A J, Georgeson M A (1999). Sensitivity to modulations of luminance and contrast in visual white noise: separate mechanisms with similar behaviour. Vision Research. 39, 2697-2716.
  • 50. Hammett S T, Georgeson M A, Gorea A (1998) Motion blur and motion sharpening: temporal smear and local contrast non-linearity. Vision Research 38, 2099-2108.
  • 49. Georgeson M A (1998) Edge-finding in human vision: a multi-stage model based on the perceived structure of plaids. Image & Vision Computing 16, No. 6-7, 389-405.
  • 48. Georgeson M A, Meese T S (1997). Perception of stationary plaids: the role of spatial filters in edge localisation. Vision Research. 38, 3255-3271.
  • 47. Georgeson M A, Freeman T C A (1997) Perceived location of bars and edges in 1-D images: Computational models and Human Vision. Vision Research. 37, 127-142.
  • 46. Georgeson M A, Meese T S (1996). Perceived structure of plaids implies variable combination of oriented filters in edge-finding. In Rogowitz B E and Allebach J P (eds.) Human Vision and Electronic Imaging, Proc. SPIE, 2657, 175-189.
  • 45. Meese T S, Georgeson M A (1996b) Spatial filter combination in human pattern vision: channel interactions revealed by adaptation. Perception 25, 255-277.
  • 44. Meese T S, Georgeson M A (1996a) The tilt aftereffect in plaids & gratings: channel codes, local signs and 'patchwise transforms'.Vision Research. 36, 1421-1438.
  • 43. Georgeson M A, Freeman T C A & Scott-Samuel, N E (1996) Sub-pixel accuracy: psychophysical validation of an algorithm for fine positioning and movement of dots on visual displays. Vision Research. 36, 605-612.
  • 42. Georgeson M A (1994) 'From filters to features: Location, Orientation, Contrast and Blur'. In Higher Order Processing in the Visual System (Ciba Foundation Symposium 184), pp 147-165. Wiley, Chichester.
  • 41. Georgeson M A & Shackleton T M (1994) 'Perceived contrast of gratings and plaids: non-linear summation across oriented filters' Vision Research 34, 1061-1075.
  • 40. Georgeson M A (1992) 'Human vision combines oriented filters to compute edges' Proceedings of the Royal Society B 249, 235-245.
  • 39. Greenlee M W, Georgeson M A, Magnussen S & Harris J P (1992) 'The decay of adaptation to spatial contrast: a response to David Rose' Vision Research 32, 1785-1788.
  • 38. Georgeson M A & Shackleton T M (1992) 'No evidence for dichoptic motion sensing: a reply to Carney & Shadlen' Vision Research 32, 193-198.
  • 37. Georgeson M A (1991b) 'Over the limit: encoding contrast above threshold in human vision' in "Vision and Visual Dysfunction, Vol 5: Limits of visual perception", ed. JJ Kulikowski, V Walsh, I J Murray. Macmillan, London. Pp 109-119.
  • 36. Georgeson M A (1991a) 'Contrast over-constancy'. J. Opt. Soc. Am. A 8, 579-586.
  • 35. Greenlee M W, Georgeson M A, Magnussen S & Harris J P (1991) 'The time-course of adaptation to spatial contrast' Vision Research 31, 223-236.
  • 34. Georgeson M A & Harris M G (1990) 'The temporal range of motion sensing and motion perception' Vision Research 30, 615-619.

1980s

  • 33. Georgeson M A & Shackleton T M (1989) 'Monocular motion sensing, binocular motion perception'. Vision Research 29, 1511-1523.
  • 32. Georgeson M A (1988) 'Spatial phase dependence and the role of motion detection in monocular and dichoptic forward masking'. Vision Res. 28, 1193-1205.
  • 31. Swanson W H, Georgeson M A & Wilson H R (1988) 'Comparison of contrast transfer functions at suprathreshold contrasts'. Vision Res. 28, 457-459.
  • 30. Georgeson M A & Georgeson J M (1987) 'Facilitation and masking of briefly presented gratings; time-course and contrast dependence'. Vision Res. 27, 369-379.
  • 29. Georgeson M A (1987) 'Temporal properties of spatial contrast vision'. Vision Res. 27, 765-780.
  • 28. Harris M G & Georgeson M A (1986) 'Sustained and transient temporal integration functions depend on spatial frequency, not grating area'. Vision Res. 26, 1779-1782.
  • 27. Georgeson M A (1985c) 'Inferring cortical organization from subjective visual patterns' in "Models of the Visual Cortex", eds. D Rose & V Dobson. Wiley, London.
  • 26. Georgeson M A (1985b) 'Apparent spatial frequency and contrast of gratings: separate effects of contrast and duration'. Vision Res. 25, 1721-1727.
  • 25. Georgeson M A (1985a) 'The effect of spatial adaptation on perceived contrast'. Spatial Vision 1, 103-112.
  • 24. Georgeson M A & Turner R S E (1985) 'Afterimages of sinusoidal, square-wave and compound gratings'. Vision Res. 25, 1709-1720.
  • 23. Georgeson M A & Georgeson J M (1985) 'On seeing temporal gaps between gratings: a criterion problem for measurement of visible persistence'. Vision Res. 25, 1729-1733.
  • 22. Georgeson M A (1984) 'Eye movements, afterimages and monocular rivalry'. Vision Res. 24, 1311-1319.
  • 21. Georgeson M A & Turner R S E (1984) 'Stability of phase recognition in complex spatial waveforms'. Vision Res. 24, 851-858.
  • 20. Georgeson M A & Harris M G (1984) 'Spatial selectivity of contrast adaptation: models and data'. Vision Res. 24, 729-741.
  • 19. Georgeson M A & Harris M G (1981) 'Size constancy does not fail below half a degree'. Nature 289, 826.
  • 18. Georgeson M A & Reddin S K (1981) 'Adaptation to gratings: equal spatial selectivity for light and dark bar width'. Vision Res. 21, 419-421
  • 17. Georgeson M A (1980c) 'The perceived spatial frequency, contrast and orientation of illusory gratings'. Perception 9, 695-712.
  • 16. Georgeson M A (1980b) 'Spatial frequency analysis in early visual processing'. Phil. Trans. Roy. Soc. B290, 11-22. Also in "The Psychology of Vision", eds. C Longuet-Higgins & N S Sutherland; Royal society, 1980.
  • 15. Georgeson M A (1980a) 'The graph-paper effect: subjective stereoscopic patterns induced by moving gratings'. Perception 9, 503-522.
  • 14. Georgeson M A & Phillips R (1980) 'Angular selectivity of monocular rivalry: experiment and computer simulation'. Vision Res. 20, 1007-1013.

1970s

  • 13. Georgeson M A (1979b) 'Spatial frequency analysis and human vision' in "Tutorial Essays in Psychology, Vol. II", ed. N S Sutherland. L. Erlbaum Associates, Hillsdale N.J.
  • 12. Georgeson M A (1979a) 'Random-dot stereograms of real objects: observations on stereo faces and moulds'. Perception 8, 585-588.
  • 11. Georgeson M A & Harris M G (1978) 'Apparent foveo-fugal drift of counterphase gratings'. Perception 7, 527-536.
  • 10. Sullivan G D & Georgeson M A (1977) 'The missing fundamental illusion: variation of spatio-temporal characteristics with dark adaptation'. Vision Res. 17, 977-981.
  • 9. Georgeson M A (1976b) 'Psychophysical hallucinations of orientation and spatial frequency'. Perception 5, 99-111.
  • 8. Georgeson M A (1976a) 'Antagonism between channels for pattern and movement in human vision'. Nature 259, 413-415.
  • 7. Georgeson M A & Sullivan G D (1975) 'Contrast constancy: deblurring in human vision by spatial frequency channels'. J. Physiol. 252, 627-656.
  • 6. Georgeson M A (1974) 'Is texture-density contrast and adaptation or an inhibition ?' Nature 249, 85-86.
  • 5. Georgeson M A & Blakemore C B (1973) 'Apparent depth and the Muller-Lyer illusion'. Perception 2, 225-234.
  • 4. Georgeson M A (1973) 'Spatial frequency selectivity of a visual tilt illusion'. Nature 245, 43-45.
  • 3. Sullivan G D, Georgeson M A & Oatley K (1972) 'Channels for spatial frequency selection and the detection of single bars by the human visual system'. Vision Res. 12, 383-394.
  • 2. Blakemore C B, Carpenter R H S & Georgeson M A (1971) 'Lateral thinking about lateral inhibition'. Nature New Biology 234, 418-419.
  • 1. Blakemore C B, Carpenter R H S & Georgeson M A (1970) 'Lateral inhibition between orientation detectors in the human visual system'. Nature 228, 37-39

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Lab Notes for Visual Psychophysics

Calibration & Visual display issues

1. Gamma correction and CRT calibration (2006)
2. On making visual noise (1999, 2003)
3. Measuring the crosstalk in stereo goggles (2005)

Signal Detection Theory

4. Lecture Notes: Signal Detection Theory - Introduction (1999-2006)
5. Lecture Notes: Signal Detection Theory & Psychophysics (2006)
6. Research Seminar: Using psychophysics to study perception (2007)
[ A talk on Signal Detection Theory and the single-interval psychometric function]
7. Download Excel file for SDT calculations: Yes-No and 2AFC (2006)
Note: This file is supplied 'as is', for information & guidance only.
I cannot undertake to support its use, nor can I guarantee
that it is appropriate for your application

Useful links & free software

PsychToolbox - free Matlab software for visual psychophysics on Mac & PC
Psignifit
- free software for fitting psychometric functions to data
CRS Ltd
- commercial equipment & software for vision research
NIH Image
- free software for digital image-processing

News & Views

1. Perception & Action - You ain't seen nothin' yet (Perception 1997)
2. Visual aftereffects - cortical neurons change their tune (Current Biology 2004)

EPSRC grant S07261/01: Final report & manuscripts 2007

Project: Mechanisms of shading & texture analysis in perception of 3-D surfaces

Final report – Summary of work on the project
R1. Depth propagation & Surface contruction: Georgeson et al (2007)
R2. Depth facilitation & Uncertainty: Georgeson et al (2007)
R3. Is there a sun? Probing the default illuminant for human shape-from-shading: Schofield et al (2007)
R4. Analysis of shading versus material changes in images: Schofield et al (2007)
R5. Technical Report: Greyscale CRT calibration for psychophysics: Georgeson (2007)

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Vision Science Demos

The motion aftereffect (MAE) is well known. Staring for a few seconds at motion in one direction (eg clockwise) will make a stationary test pattern appear to move the opposite way (eg anti-clockwise). The effect is compelling, and involves a temporary change in the responsiveness of motion-detecting cells in the visual parts of the brain. It is used by vision scientists as a research tool, to study how visual motion perception works.

Much less well-known is the finding that adapting to flickering images that are not moving can also produce an MAE - the 'motion aftereffect without motion' (Anstis, 1990, Perception 19, 301-306).  Recently I discovered how to generalize this effect to produce motion in any arbitrary test image, in any direction.  The effect most probably involves adapting cells in the retina, not the brain, that sense the way local image brightness changes over time. These cells then feed into the computation of motion by the brain.

Four videos of this effect are given below. Enjoy!

Motion aftereffect without motion - on a test image that isn't there

Presented at VSS conference demo night, Naples, Florida, May 2011
Instructions for the Demos
Click play (>). Fix your gaze steadily & carefully on the central letter (A, becomes T, then B)
1. Adapt for 4 sec; the image is flickering but not moving.
2. Test: stationary patterns; do they seem to move? In what way? 
3. Blank frames: there's no test image at all, but do you see moving images?

[ If not sure, try again...all four demos are different. Try to keep your gaze fixed on the letter(s) ]

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Last update: 8th Apr 2013, 6.38 p.m.

 

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