The importance of contours for visual object recognition and discrimination

In contrast to many machine vision systems, we human observers can readily recognize solid objects and visually discriminate their 3-D shapes even under changes in viewpoint and variations in object orientation and lighting. While the importance of binocular disparity has been known since the 1830's, the importance and perceptual informativeness of visual contours for object recognition and discrimination is not adequately appreciated. This article will review those scientific contributions that demonstrate that visual contours and their deformations over time (in response to object or observer motion) carry as much or more information about object shape than other forms of visual information.

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Visual object recognition: building invariant representations over time

Journal of Biosciences ◽

10.1007/s12038-008-0083-y ◽

2008 ◽

Vol 33 (5) ◽

pp. 639-642

Author(s):

Duje Tadin ◽

Raphael Pinaud

Keyword(s):

Object Recognition ◽

Visual Object ◽

Visual Object Recognition ◽

Invariant Representations ◽

Over Time

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Haptic Shape Processing in Visual Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00548 ◽

2014 ◽

Vol 26 (5) ◽

pp. 1154-1167 ◽

Cited By ~ 19

Author(s):

Jacqueline C. Snow ◽

Lars Strother ◽

Glyn W. Humphreys

Keyword(s):

Visual Cortex ◽

Object Recognition ◽

Primary Visual Cortex ◽

Shape Recognition ◽

Visual Object ◽

Visual Object Recognition ◽

Object Shape ◽

Shape Processing ◽

Shape Selective ◽

Visual Cortical

Humans typically rely upon vision to identify object shape, but we can also recognize shape via touch (haptics). Our haptic shape recognition ability raises an intriguing question: To what extent do visual cortical shape recognition mechanisms support haptic object recognition? We addressed this question using a haptic fMRI repetition design, which allowed us to identify neuronal populations sensitive to the shape of objects that were touched but not seen. In addition to the expected shape-selective fMRI responses in dorsal frontoparietal areas, we observed widespread shape-selective responses in the ventral visual cortical pathway, including primary visual cortex. Our results indicate that shape processing via touch engages many of the same neural mechanisms as visual object recognition. The shape-specific repetition effects we observed in primary visual cortex show that visual sensory areas are engaged during the haptic exploration of object shape, even in the absence of concurrent shape-related visual input. Our results complement related findings in visually deprived individuals and highlight the fundamental role of the visual system in the processing of object shape.

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Prefrontal Control Over Occipital Responses to Crossmodal Overlap Varies Across the Congruency Spectrum

Cerebral Cortex ◽

10.1093/cercor/bhy168 ◽

2018 ◽

Vol 29 (7) ◽

pp. 3023-3033 ◽

Cited By ~ 4

Author(s):

Johan N Lundström ◽

Christina Regenbogen ◽

Kathrin Ohla ◽

Janina Seubert

Keyword(s):

Object Recognition ◽

Information Exchange ◽

Visual Information ◽

Effective Connectivity ◽

Adult Population ◽

Linear Increase ◽

Cortical Activation ◽

Visual Object ◽

Visual Object Recognition ◽

Semantic Object

Abstract While matched crossmodal information is known to facilitate object recognition, it is unclear how our perceptual systems encode the more gradual congruency variations that occur in our natural environment. Combining visual objects with odor mixtures to create a gradual increase in semantic object overlap, we demonstrate high behavioral acuity to linear variations of olfactory–visual overlap in a healthy adult population. This effect was paralleled by a linear increase in cortical activation at the intersection of occipital fusiform and lingual gyri, indicating linear encoding of crossmodal semantic overlap in visual object recognition networks. Effective connectivity analyses revealed that this integration of olfactory and visual information was achieved by direct information exchange between olfactory and visual areas. In addition, a parallel pathway through the superior frontal gyrus was increasingly recruited towards the most ambiguous stimuli. These findings demonstrate that cortical structures involved in object formation are inherently crossmodal and encode sensory overlap in a linear manner. The results further demonstrate that prefrontal control of these processes is likely required for ambiguous stimulus combinations, a fact of high ecological relevance that may be inappropriately captured by common task designs juxtaposing congruency and incongruency.

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