Structure from motion (psychophysics)

This article is about structure from motion in psychophysics.

In visual perception, structure from motion (SFM) refers to how humans recover depth structure from object's motion. The human visual field has an important function: capturing the three-dimensional structures of an object using different kinds of visual cues.[1]

SFM is a kind of motion visual cue that uses motion of two-dimensional surfaces to demonstrate three-dimensional objects,[2] and this visual cue works really well even independent of other depth cues.[3] Psychological, especially psychophysical studies have been focused on this topic for decades.

Psychophysical studies

In a 1953 study on SFM done by Wallach and O'Connell the kinetic depth effect was tested. They found that by turning shadow images of a three dimensional object can be used as a cue to recover the structure of the physical object quite well.[4] Johansson's study conducted in 1973 discovered our ability to perceive human form of walking or dancing simply from projected motion of several points on the body,[5] this motion pattern was later termed as biological motion.[6]

A proposition for how we generate a 3D surface representation of an object is that our visual system uses the spatial and temporal integration of information to detect the structure.[7] Other studies agree that SFM is a process which contains several aspects:[8] the perception of rotating direction,[9] perceived orientation of rotation axis,[9] space interpolation effects[10] and object recognition.

Given its complexity, SFM involves very high-level of visual processing. Studies have shown that MT, rather than V1 (the primary visual cortex), is directly involved in the generation of the SFM perception.[8] Neurons in MT are also triggered by motion parallax and show depth signs independent of other depth cues,[11] and MT's representation of three-dimensions also confirms the close relationship between MT area and SFM. However, V1 neuron activities are indirectly related to SFM perception, which receives general feedback from MT.[8][12]

The importance of motion perception of SFM in detecting three-dimensional structure is also demonstrated by several studies. 3D objects can be perceived from the 2D projections of the moving object on a screen, but not the stationary 2D images.[4][13] Also, one essential condition for SFM perception to occur accurately is that the projection of the object must has simultaneously changing contour and lines.[4] A relatively invariant point lifetime threshold of SFM (50-85 msec) was found, and it turns out that this threshold is close to the threshold of velocity measurement, which suggests that velocity measurement is involved in the SFM processing procedure.[7] Given such mechanism, human visual system can derive an accurate model of SFM even with the presence of noise.[14]

Being a complex process, SFM requires more than orthographic projections approximations, though many experiments used orthographic projections. Studies have found that higher order visual cues like acceleration and perspective projection are involved in this process rather than just first order flow (meaning SFM is partly a top down process).[15] Combination of all orders of visual cues gives the best estimate of 3D objects.[15]

See also

References
  1. Whitehead, Bruce A. (July 1981). "James J. Gibson: The ecological approach to visual perception. Boston: Houghton Mifflin, 1979, 332 pp". Behavioral Science. 26 (3): 308–309. doi:10.1002/bs.3830260313. ISSN 0005-7940.
  2. "APA Upgrades APA PsycNET Content Delivery Platform". PsycEXTRA Dataset. 2017. Retrieved 2020-06-16.
  3. Rogers, Brian; Graham, Maureen (April 1979). "Motion Parallax as an Independent Cue for Depth Perception". Perception. 8 (2): 125–134. doi:10.1068/p080125. ISSN 0301-0066.
  4. "APA PsycNet". psycnet.apa.org. Retrieved 2020-06-28.
  5. Aloimonos, J.; Brown, C. M. (1989-04-01). "On the kinetic depth effect". Biological Cybernetics. 60 (6): 445–455. doi:10.1007/BF00204700. ISSN 1432-0770.
  6. Johansson, Gunnar (1973-06-01). "Visual perception of biological motion and a model for its analysis". Perception & Psychophysics. 14 (2): 201–211. doi:10.3758/BF03212378. ISSN 1532-5962.
  7. Treue, Stefan; Husain, Masud; Andersen, Richard A. (1991-01-01). "Human perception of structure from motion". Vision Research. 31 (1): 59–75. doi:10.1016/0042-6989(91)90074-F. ISSN 0042-6989.
  8. Grunewald, Alexander; Bradley, David C.; Andersen, Richard A. (2002-07-15). "Neural Correlates of Structure-from-Motion Perception in Macaque V1 and MT". The Journal of Neuroscience. 22 (14): 6195–6207. doi:10.1523/JNEUROSCI.22-14-06195.2002. ISSN 0270-6474. PMC 6757912. PMID 12122078.
  9. Pollick, F. E.; Nishida, S.; Koike, Y.; Kawato, M. (July 1994). "Perceived motion in structure from motion: pointing responses to the axis of rotation". Perception & Psychophysics. 56 (1): 91–109. doi:10.3758/bf03211693. ISSN 0031-5117. PMID 8084735.
  10. Treue, S.; Andersen, R. A.; Ando, H.; Hildreth, E. C. (January 1995). "Structure-from-motion: perceptual evidence for surface interpolation". Vision Research. 35 (1): 139–148. doi:10.1016/0042-6989(94)e0069-w. ISSN 0042-6989. PMID 7839603.
  11. Nadler, Jacob W.; Angelaki, Dora E.; DeAngelis, Gregory C. (2008-04-03). "A neural representation of depth from motion parallax in macaque visual cortex". Nature. 452 (7187): 642–645. doi:10.1038/nature06814. ISSN 1476-4687. PMC 2422877. PMID 18344979.
  12. Maunsell, JH; van Essen, DC (1983-12-01). "The connections of the middle temporal visual area (MT) and their relationship to a cortical hierarchy in the macaque monkey". The Journal of Neuroscience. 3 (12): 2563–2586. doi:10.1523/jneurosci.03-12-02563.1983. ISSN 0270-6474.
  13. Vuong, Quoc C; Friedman, Alinda; Plante, Courtney (January 2009). "Modulation of Viewpoint Effects in Object Recognition by Shape and Motion Cues". Perception. 38 (11): 1628–1648. doi:10.1068/p6430. ISSN 0301-0066.
  14. Hildreth, Ellen C.; Grzywacz, Norberto M.; Adelson, Edward H.; Inada, Victor K. (1990-01-01). "The perceptual buildup of three-dimensional structure from motion". Perception & Psychophysics. 48 (1): 19–36. doi:10.3758/BF03205008. ISSN 1532-5962.
  15. "APA PsycNet". psycnet.apa.org. Retrieved 2020-06-21.
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