Johannes M. Zanker (2005) A computational analysis of separating motion signals in transparent random dot kinematograms. Spatial Vision, 18 (4). pp. 431-445. ISSN 0169-1015
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When multiple motion directions are presented simultaneously within the same region of the visual field human observers see motion transparency. This perceptual phenomenon requires from the visual system to separate different motion signal distributions, which are characterised by distinct means that correspond to the different dot directions and variances that are determined by the signal and processing noise. Averaging of local motion signals can be employed to reduce noise components, but such pooling could at the same time lead to the averaging of different directional signal components, arising from spatially adjacent dots moving in different directions, which would reduce the visibility of transparent directions. To study the theoretical limitations of encoding transparent motion by a biologically plausible motion detector network, the distributions of motion directions signalled by a motion detector model (2DMD) were analysed here for Random Dot Kinematograms (RDKs). In sparse dot RDKs with two randomly interleaved motion directions, the angular separation that still allows us to separate two directions is limited by the internal noise in the system. Under the present conditions direction differences down to 30 deg could be separated. Correspondingly, in a transparent motion stimulus containing multiple motion directions, more than eight directions could be separated. When this computational analysis is compared to some published psychophysical data, it appears that the experimental results do not reach the predicted limits. Whereas the computer simulations demonstrate that even an unsophisticated motion detector network would be appropriate to represent a considerable number of motion directions simultaneously within the same region, human observers usually are restricted to seeing not more than two or three directions under comparable conditions. This raises the question why human observers do not make full use of information that could be easily extracted from the representation of motion signals at the early stages of the visual system.
This is a Published version This version's date is: 2005 This item is peer reviewed
https://repository.royalholloway.ac.uk/items/8c8439bf-9966-3dc7-63e4-379132e3cb45/1/
Deposited by Al Dean (ZSRA118) on 19-Mar-2010 in Royal Holloway Research Online.Last modified on 05-Jan-2011
(C) 2005 Brill Academic Publishers, whose permission to mount this version for private study and research is acknowledged. The repository version is the author's final draft.
Adelson, E. H. and Bergen, J. R. (1985). Spatiotemporal energy models for the perception of motion, J. Opt. Soc. Amer. A 2, 284–299.
Ball, K. and Sekuler, R. (1981). Cues reduce direction uncertainty and enhance motion detection, Perception and Psychophysics 30, 119–128.
Benton, C. P. and Curran, W. (2003). Direction repulsion goes global, Current Biology 13, 767–771.
Borst, A. and Egelhaaf, M. (1989). Principles of visual motion detection, Trends in Neuroscience 12, 297–306.
Braddick, O. J. (1980). Low-level and high-level processes in apparent motion, Philosoph. Trans. Roy. Soc. (Biology) 290, 137–151.
Braddick, O. J. and Qian, N. (2001). The organization of global motion and transparency, in: Motion Vision: Computational, Neural and Ecological Constraints, Zanker, J. M. and Zeil, J. (Eds), pp. 85–112. Springer, Berlin.
Braun, J. (2000). Intimate attention, Nature 408, 154–155.
Castiello, U. and Umilta, C. (1992). Splitting focal attention, J. Exp. Psychol.: Human Perception and Performance 18, 837–848.
Cavanagh, P. (1992). Attention-based motion perception, Science 257, 1563–1565.
Chaudhuri, A. (1990).Modulation of the motion after-effect by selective attention, Nature 344, 60–62.
Chawla, D., Rees, G. and Friston, K. J. (1999). The physiological basis of attentional modulation in extrastriate visual areas, Nature Neuroscience 2, 671–676.
Curran, W. and Braddick, O. J. (2000). Speed and direction of locally-paired dot patterns, Vision Research 40, 2115–2124.
Felisberti, F. M. and Zanker, J. M. (2004). Does attention affect transparent motion perception? Perception 33, S 124.
Gibson, J. J. (1979). The Ecological Approach to Visual Perception. Lawrence Erlbaum Associates, Hillsdale, NJ, USA.
Götz, K. G. (1965). Die optischen Übertragungseigenschaften der Komplexaugen von Drosophila, Kybernetik 2, 215–221.
Green, D. M. and Swets, J. A. (1966). Signal Detection Theory and Psychophysics. Wiley, New York.
Hildreth, E.-C. and Koch, C. (1987). The analysis of visual motion: From computational theory to neuronal mechanisms, Ann. Rev. Neurosci. 10, 477–533. Hiris, E. and Blake, R. (1996). Directon repulsion in motion transparency, Visual Neuroscience 13, 187–197.
Langley, K. (1999). Computational models of coherent and transparent plaid motion, Vision Research 39, 87–108.
Lu, Z.-L. and Sperling, G. (1995). Attention-generation apparent motion, Nature 377, 237–239.
Marr, D. and Hildreth, E.-C. (1980). Theory of edge detection, Proc. Roy. Soc. London B 207, 187– 217.
Marshak, D.W. and Sekuler, R. (1979).Mutual repulsion between moving visual targets, Science 205, 1399–1401.
Mather, G. and Moulden, B. (1980). A simultaneous shift in apparent directions: further evidence for a distibution-shift model of direction encoding, Quart. J. Exper. Psychol. 32, 325–333.
Mulligan, J. B. (1993).Motion transparency is restricted to two planes, Investigat. Ophthalmol. Visual Sci. 33, 1049.
Nakayama, K. (1985). Biological image motion processing: a review, Vision Research 25, 625–660.
Pylyshyn, Z. W. and Storm, R. W. (1988). Tracking multiple independent targets: evidence for a parallel tracking mechanism, Spatial Vision 3, 179–197.
Qian, N. and Andersen, R. A. (1997). A physiological for motion-stereo integration and a unified explanation of Pulfrich-like phenomena, Vision Research 37, 1683–1698.
Qian, N., Andersen, R. A. and Adelson, E. H. (1994). Transparent motion perception as detection of unbalanced motion signals. I. Psychophysics, J. Neurosci. 14, 7357–7366. Rauber, H.-J. and Treue, S. (1999). Revisiting motion repulsion: evidence for a general phenomenon? Vision Research 39, 3187–3196.
Raymond, J. E. (2000). Attentional modulation of visual motion perception, Trends in Cognitive Sciences 4, 42–50. Raymond, J. E., O’Donnell, H. L. and Tipper, S. P. (1998). Priming reveals attentional modulation of human motion sensitivity, Vision Research 38, 2863–2867.
Regan, D. (1991). Spatial vision for objects defined by colour, contrast, binocular disparity and motion parallax, in: Vision and Visual Dysfunction 10 Spatial Vision, Regan, D. (Ed.), pp. 135–178. Macmillan Press, Houndsmill.
Reichardt, W. (1987). Evaluation of optical motion information by movement detectors, J. Compar. Physiol. A161, 533–547. Sekuler, R., Anstis, S. M., Braddick, O. J., Brandt, T., Movshon, J. A. and Orban, G. A. (1990). The perception of motion, in: Visual Perception. The Neurophysiological Foundations, Spillmann, L. and Werner, J. S. (Eds), pp. 205–230. Academic Press, San Diego, CA, USA.
Smith, A. T., Curran, W. and Braddick, O. J. (1999). What motion distributions yield global transparency and spatial segmentation? Vision Research 39, 1121–1132.
Snowden, R. J. and Verstraten, F. A. J. (1999). Motion transparency: making models of motion transparency transparent, Trends in Cognitive Sciences 3, 369–377. Analysis of motion signals in kinematograms 445
Srinivasan,M. V. and Dvorak, D. R. (1980). Spatial processing of visual information in the movementdetecting pathway of the fly, J. Compar. Physiol. 140, 1–23.
Treue, S. and Trujillo, J. C. M. (1999). Feature-based attention influences motion processing gain in macaque visual cortex, Nature 399, 575–579.
Treue, S., Hol, K. and Rauber, H.-J. (2000). Seeing multiple directions of motion — physiology and psychophysics, Nature Neuroscience 3, 270–276.
Van Doorn, A. J. and Koenderink, J. J. (1982). Spatial properties of the visual detectability of moving spatial white noise, Exp. Brain Res. 45, 189–195.
Van Santen, J. P. H. and Sperling, G. (1985). Elaborated Reichardt detectors, J. Opt. Soc. Amer. A 2, 300–321.
Verghese, P.,Watamaniuk, S. N. J.,McKee, S. P. and Grzywacz, N. M. (1999). Local motion detectors cannot account for the detectability of an extended trajectory in noise, Vision Research 39, 19–30.
Watson, A. B. and Ahumada, A. J. (1985). Model of human visual-motion sensing, J. Opt. Soc. Amer. A 2, 322–342.
Watson, A. B. and Eckert, M. P. (1994). Motion-contrast sensitivity: visibility of motion gradients of various spatial frequencies, J. Opt. Soc. Amer. A 11, 496–505.
Williams, D. W. and Sekuler, R. (1984). Coherent global motion percepts from stochastic local motions, Vision Research 24, 55–62.
Zanker, J. M. (1996). On the elementary mechanism underlying secondary motion processing, Proc. Roy. Soc. London B 351, 1725–1736. Zanker, J. M. (2000). Motion transparency and multiple motion directions, Investigat. Ophthalmol. Visual Sci. 41, S 720.
Zanker, J. M. (2001). Combining local motion signals: a computational study of segmentation and transparency, in: Motion Vision: Computational, Neural and Ecological Constraints, Zanker, J.M. and Zeil, J. (Eds), pp. 113–124. Springer, Berlin. Zanker, J. M. (2004). Looking at Op Art from a computational viewpoint, Spatial Vision 17, 75–94.
Zanker, J. M. and Zeil, J. (2002). An analysis of the motion signal distributions emerging from locomotion through a natural environment, in: Biologically Motivated Computer Vision 2002, Lecture Notes on Computer Vision 2525, Bülthoff, H. H., Lee, S.-W., Poggio, T. andWallraven, C. (Eds), pp. 146–156. Springer, Berlin.
Zeil, J. and Zanker, J. M. (1997). A glimpse into crabworld, Vision Research 37, 3417–3426.
Zohary, E., Scase, M. O. and Braddick, O. J. (1996). Integration across directions in dynamic random dot displays: vector summation or winner take all? Vision Research 36, 2321–2331.