Bruno G. Breitmeyer and Haluk ÖĞmen
- Published in print:
- 2006
- Published Online:
- April 2010
- ISBN:
- 9780198530671
- eISBN:
- 9780191728204
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198530671.003.0006
- Subject:
- Psychology, Cognitive Psychology
Metacontrast and motion perception have been related to each other in several ways. At a theoretical level, similarities between the temporal dynamics of visual masking and motion perception have ...
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Metacontrast and motion perception have been related to each other in several ways. At a theoretical level, similarities between the temporal dynamics of visual masking and motion perception have been noted by several investigators. The perceived clarity/blur of moving targets (also known as ‘motion deblurring’) is another phenomenon that reveals a close relationship between metacontrast and motion. The chapter provides a review of basic findings on the motion deblurring, followed by a discussion of mechanisms that can account for this phenomenon. The models discussed include those that rely on motion estimation-compensation mechanisms as well as those that use inhibitory mechanisms. Simulations of the RECOD model pertaining to motion deblurring are also presented.Less
Metacontrast and motion perception have been related to each other in several ways. At a theoretical level, similarities between the temporal dynamics of visual masking and motion perception have been noted by several investigators. The perceived clarity/blur of moving targets (also known as ‘motion deblurring’) is another phenomenon that reveals a close relationship between metacontrast and motion. The chapter provides a review of basic findings on the motion deblurring, followed by a discussion of mechanisms that can account for this phenomenon. The models discussed include those that rely on motion estimation-compensation mechanisms as well as those that use inhibitory mechanisms. Simulations of the RECOD model pertaining to motion deblurring are also presented.
Michael F. Land and Dan-Eric Nilsson
- Published in print:
- 2012
- Published Online:
- December 2013
- ISBN:
- 9780199581139
- eISBN:
- 9780191774652
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199581139.003.0009
- Subject:
- Biology, Animal Biology
Animals with limited spatial vision use a variety of strategies (kineses and taxes) to navigate towards appropriate light environments. Nearly all animals with good vision have a repertoire of eye ...
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Animals with limited spatial vision use a variety of strategies (kineses and taxes) to navigate towards appropriate light environments. Nearly all animals with good vision have a repertoire of eye movements. The majority show a pattern of stable fixations with fast saccades that shift the direction of gaze. These movements may be made by the eyes themselves, or the head, or in some insects the whole body. The main reason for keeping gaze still during fixations is the need to avoid the blur that results from the long response time of the photoreceptors. Blur begins to degrade the image at a retinal velocity of about one receptor acceptance angle per response time. Some insects (e.g., hoverflies) stabilize their gaze much more rigidly than this rule implies, and it is suggested that the need to see the motion of small objects against a background imposes even more stringent conditions on image motion. A third reason for not allowing rotational image motion is to prevent contamination of the translational flow-field, by which a moving animal can judge its heading and the distances of objects. Head-bobs in birds can be thought of as of translational for stabilising the lateral image while walking. Some animals do let their eyes rotate smoothly, and these include some heteropod molluscs, copepods, mantis shrimps, jumping spiders, and water beetle larvae, all of which have narrow linear retinas that scan across the surroundings.Less
Animals with limited spatial vision use a variety of strategies (kineses and taxes) to navigate towards appropriate light environments. Nearly all animals with good vision have a repertoire of eye movements. The majority show a pattern of stable fixations with fast saccades that shift the direction of gaze. These movements may be made by the eyes themselves, or the head, or in some insects the whole body. The main reason for keeping gaze still during fixations is the need to avoid the blur that results from the long response time of the photoreceptors. Blur begins to degrade the image at a retinal velocity of about one receptor acceptance angle per response time. Some insects (e.g., hoverflies) stabilize their gaze much more rigidly than this rule implies, and it is suggested that the need to see the motion of small objects against a background imposes even more stringent conditions on image motion. A third reason for not allowing rotational image motion is to prevent contamination of the translational flow-field, by which a moving animal can judge its heading and the distances of objects. Head-bobs in birds can be thought of as of translational for stabilising the lateral image while walking. Some animals do let their eyes rotate smoothly, and these include some heteropod molluscs, copepods, mantis shrimps, jumping spiders, and water beetle larvae, all of which have narrow linear retinas that scan across the surroundings.
