Global motion perception from multiple gabor arrays.
Doctoral thesis, UCL (University College London).
This thesis examines the perception of motion of arrays of drifting Gabors (sinusoidal grating modulated by a static Gaussian function). Arrays of several Gabor patches provide ambiguous motion signals to the visual system and must be integrated over space to extract a globally consistent motion perception. Chapter 1 is a general introduction to the field of motion integration and a literature review. Chapters 2 to 5 use psychophysical techniques to explore motion perception as well as mathematical approaches from geometry and linear algebra to highlight some of the key features of these arrays and of global motion in general. Chapter 2 looks at the motion perception of Gabor arrays consistent with a rigid translation and finds that the apparent integration zone of motion signals is biased in the direction of global motion. Chapter 3 looks at how these motion signals interact with perceived spatial position and concludes that it is the global motion, not the local motion, which drives the mislocalisation of drifting Gabors. Chapter 4 looks at more complex global motion patterns, such as rotation and expansion, derived from the ambiguous motion of Gabor arrays. The results suggest that the visual system is at least as good at extracting this motion as it is for translation. In chapter 5 I construct a Gabor array that is consistent with multiple global solutions. I present a mathematical consideration of the properties of this construction before psychophysical studies show that the perceived motion varies with stimulus position within the visual field. This result is not explicable in light of existing models of global motion. The final chapter contains a discussion of the project as a whole.
|Title:||Global motion perception from multiple gabor arrays|
|Additional information:||Permission for digitisation not received|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > CoMPLEX - Maths and Physics in the Life Sciences and Experimental Biology|
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