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Titolo:
Regularization in a neural model of motion perception
Autore:
Langley, K;
Indirizzi:
Univ London Univ Coll, Dept Psychol, London WC1E 6BT, England Univ London Univ Coll London England WC1E 6BT , London WC1E 6BT, England
Titolo Testata:
VISION RESEARCH
fascicolo: 17, volume: 41, anno: 2001,
pagine: 2273 - 2283
SICI:
0042-6989(200108)41:17<2273:RIANMO>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOVING 2-DIMENSIONAL PATTERNS; PERCEIVED DIRECTION; IMAGE VELOCITY; VISUAL-CORTEX; OPTICAL-FLOW; AREA MT; RESPONSES; CONTRAST; DEPENDS; SPEED;
Keywords:
coherent motion; computational model; motion opponency; quadratic programming; regularization;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
31
Recensione:
Indirizzi per estratti:
Indirizzo: Langley, K Univ London Univ Coll, Dept Psychol, Gower St, London WC1E 6BT,England Univ London Univ Coll Gower St London England WC1E 6BT England
Citazione:
K. Langley, "Regularization in a neural model of motion perception", VISION RES, 41(17), 2001, pp. 2273-2283

Abstract

Neurons in sensory systems encode and transmit information about attributes of the environment. Much of the information transmitted by spiking neurons appears to be encoded in the rate at which they fire. This rate necessarily has a positive value. In this paper, the implication of this constraint for models of motion detection is examined. The detection of image motion is represented mathematically as a quadratic programming problem in which variables used to represent image speed are restricted to positive values. This novel representation requires that additional constraints are introducedto stabilize motion computations because quadratic programming problems require a surplus of unknowns to code for image speed. Two further constraints are introduced into the model to take into account possible cases of image degeneracy. They are based upon (i) an a priori preference for small image speeds, and (ii) the assumption that image motion parallel to contours ofconstant intensity for a one-dimensional signal is zero. The latter assumption is shown to account for perceived biases in speed reported for type I plaid patterns [Castet, E. & Morgan, M. (1996). Apparent speed of type-I symmetrical plaids. Vision Research 36, 223-32]. The model suggests that the visual system uses separate constraints to stabilize motion computations. One set of constraints arises from the nature of the motion detection process itself, while another two constraints take into account possible cases ofdegeneracy where image contrast is low or near zero and where the image function is one-dimensional and the aperture problem prevails. (C) 2001 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/11/20 alle ore 03:24:04