Notes � Parker, stereopsis

Greg Detre

Tuesday, 06 November, 2001

Prof. Andrew Parker

 

Tutorial plans

Fri week 7 @15.00 � stereopsis

after that, maybe motion (+ colour???)

Essay title

Which influence has been stronger: the influence of AI on the physiology of stereopsis, or the reverse?

Reading

Background

1. Rosenblith, W. (1961) Sensory Communication Collection of short articles (particularly Barlow, Attneave, Rushton, Reichardt).

either: CCC 153.6 RO

or:�������� RSL Openshelf Physiol. K 19c

2. Marr, D. (1982) Vision W.H. Freeman.

CCC

3. R.W. Rodieck (1998) The First Steps in Seeing Sinauer Associates, Inc.

too much hassle � not in Hooke or CCC

4. Zeki, S. (1995) A Vision of the Brain Blackwell Scientic.

got from Hooke

Fundamentals

Chapter 28 by Clay Reid (1999) in Fundamentals of Neuroscience, edited by M.J. Zigmond, pp 821-853.

CCC 573.8 Zi

Binocular vision reviews

Cumming, B.G. and DeAngelis, G.C. (2001) �The physiology of stereopsis." Annual Review of Neuroscience 24 203-238

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Parker, A. J., Cumming, B. G., and Dodd, J. V. (2000). Binocular neurons and the perception of depth. In Gazzaniga, M., editor, The Cognitive Neurosciences, pages 263- 278. MIT Press.

Poggio, G. F. (1995). Mechanisms of stereopsis in monkey visual cortex, Cerebral Cortex, 3:193-204.

Essential Papers

Barlow, H., Blakemore, C., and Pettigrew, J. (1967). The neural mechanisms of binocular depth discrimination. J. Physiol. London, 193:327-342.

RSL Openshelf Physiol. Per. 1

Cumming, B. G. and Parker, A. J. (1997). Responses of primary visual cortical neurons to binocular disparity without the perception of depth. Nature, 389:280-283.

DeAngelis, G. C., Cumming, B. G., and Newsome, W. T. (1998). Cortical area MT and the perception of stereoscopic depth. Nature, 394:677-80.

RSL Openshelf Gen/Bio per

Ferster, D. (1981). A comparison of binocular depth mechanisms in areas 17 and 18 of cat visual cortex. J. Physiol. London, 315:623-655.

Ohzawa, I., DeAngelis, G. C., and Freeman, R. D. (1990). Stereoscopic depth discrimination in the visual cortex: Neurons ideally suited as disparity detectors. Science, 249:1037-1041.

downloaded

Additional Reading

Cumming, B. G. and Parker, A. J. (1999). Binocular neurons in V1 of awake monkeys are selective for absolute, not relative, disparity. J. Neuroscience, 19:5602-5618.

Cumming, B. G. and Parker, A. J. (2000). Binocular neurons in V1 respond to false stereo matches in sinusoidal gratings. J. Neuroscience, 20 (12): 4758-4767

Hubel, D. and Wiesel, T. (1962). Receptive fields, binocular interaction and functional architecture in the cat's visual cortex. J. Physiol. London, 160:106-154.

Hubel, D. H. and Livingstone, M. S. (1987). Segregation of form, color, and stereopsis in primate area 18. J. Neuroscience, 7:3378-415.

Janssen, P., Vogels, R., and Orban, G. A. (1999). Macaque inferior temporal neurons are selective for disparity-defined three-dimensional shapes. Proceedings of the National Academy of Sciences, NY, 96:8217-8222.

Nikara, T., Bishop, P. O., and Pettigrew, J. D. (1968). Analysis of retinal correspondence by studying receptive fields of binocular single units in cat striate cortex. Exp. Brain Res., 6:353-72.

Poggio, G. F., Motter, B. C., Squatrito, S., and Trotter, Y. (1985). Responses of neurons in visual cortex (V1 and V2) of the alert macaque to dynamic random dot stereograms. Vision Research, 25:397-406.

Roy, J. P., Komatsu, H., and Wurtz, R. H. (1992). Disparity sensitivity of neurons in monkey extrastriate area MST. J. Neurosci., 12:2478-2492.

Notes � Kandel & Schwarz 3rd edition, ch 30, pg 454-

at distances greater than about 100 feet, the retinal images seen by each eye are almost identical

Notes � De Angelis & Cumming (2001), �The physiology of vision�

Notes � Garnham, �Artificial intelligence�, section on stereopsis in vision chapter

Mayhew and Frisby[1] proposed a third algorithm, with a binocular raw primal sketch. They identify two principles that they claim are used to solve the correspondence problem:

figural continuity and the rleatoin between the outputs of the del-squared G filters that is used to identify edge segments and bar segments � they have psychophysical evidence that supports their algorithm over Marr and Poggio�s

Definitions

disparity = expressed in terms of the difference in the angle between the line of sight and the line to the object for the two eyes. a further computation is required to ocnvert disparity into distance from the viewer, but this is straightforward.

Points

David Marr was an anomaly in many ways � few researchers can claim to have single-handedly straddled the theoretical and experimental sides of the discipline so commandingly, or shown such imagination in their proposals. Without his suggestions giving experimenters an idea of what results to look for initially, we might still be in the process of

Questions

what constitutes an AI attempt, and what a physiology one???

if our two eyes were much further apart, would our stereopsis be much more powerful??? would that be helpful??? would it also be much much harder???

what AI attempts have there been???

what�s the adjective for stereopsis???

what if we had three eyes??? would that help??? would it be easier/harder???

do glass, mirrors or transparent surfaces (e.g. water) make things more difficult???

does stereopsis include structure from motion, shading etc., or just retinal disparity stuff???

vergence???

which object do the eyes choose to verge on (which�ll have zero disparity)???

it�s based on the object that you happen to be looking at

do people still talk in terms of a 2�-D sketch etc.???

Marr

am i meant to be able to see the RDS examples in Marr's book???

are marr's algorithms implementable on a connectionist system???

De Angelis & Cumming (2001)

why a bar stimulus???

irradiance pattern???

dichoptic???

convolving???

phase vs position disparity

relative vs absolute disparity

isotropic disparity encoding???

energy model???

Gabor models???

Cumming and Parker (1997), letter to nature

what�s the advantage of using an aRDS as opposed to two random RDSs with local patch correlations???

convolving??? Convolving here means multiplying the image brightness at each point with the value of the RF at that point and summing all the products???

 

 



[1] Mayhew and Frisby (1981), �Psychophysical and computational studies twoards a theory of human stereopsis�, Artificial Intelligence, 17: 349-85