Search PubMed⌕ Search

PubMed · 7800470

Aspect graphs for visual recognition of three-dimensional objects.

Abstract

Visual representation of three-dimensional (3-D) objects in our environment is a crucial question, for human as well as for machine vision. Some basics are reviewed of a viewer-centred model of 3-D objects, aspect graphs, which represents a 3-D object by all its topologically stable visible image contours (its aspects) and by the transitions between stable image contours (the visual events). This representation takes only geometrical information about discontinuities in depth and in surface orientation into account, and other clues, such as shadows, markings, texture, etc, are disregarded. Mathematical results give some insight into the relationships between the geometry of a 3-D object and the aspect of its image contours, the techniques used to compute an aspect graph effectively, and the state of the art of this type of model in computer vision. Current research is reviewed on viewer-centred representation in cognitive science that seems to indicate that aspect graphs could also have some relevance for human vision.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

T Van Effelterre. 1994. Aspect graphs for visual recognition of three-dimensional objects.. https://doi.org/10.1068/p230563

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

A low glycaemic index breakfast cereal preferentially prevents children's cognitive performance from declining throughout the morning.

This study investigated whether the glycaemic index (GI) of breakfast cereal differentially affects children's attention and memory. Using a balanced cross-over design, on two consecutive mornings 64 children aged 6-11 years were given a high GI cereal and a low GI cereal in a counterbalanced order. They performed a series of computerised tests of attention and memory, once prior to breakfast and three times following breakfast at hourly intervals. The results indicate that children's performance declines throughout the morning and that this decline can be significantly reduced following the intake of a low GI cereal as compared with a high GI cereal on measures of accuracy of attention (M=-6.742 and -13.510, respectively, p<0.05) and secondary memory (M=-30.675 and -47.183, respectively, p<0.05).

Attention↗

Inhibitory control test is a simple method to diagnose minimal hepatic encephalopathy and predict development of overt hepatic encephalopathy.

OBJECTIVES: To compare inhibitory control test (ICT), a simple/rapid test of attention, to a standard psychometric battery (SPT) to diagnose minimal hepatic encephalopathy (MHE) and predict development of overt hepatic encephalopathy (OHE) in cirrhotic patients. METHODS: Fifty nonalcoholic cirrhotics and 50 age/educational-status-matched controls were given ICT and SPT in the same sitting. Performance impaired beyond two standard deviations of controls was considered MHE in cirrhotics. ICT results (lure/target response and lures/person) were compared between controls and cirrhotics and within cirrhotics with/without MHE. Receiver-operating characteristic analysis was used to study ICT for MHE diagnosis. Twenty subjects were administered SPT and ICT twice to assess test-retest reliability. All cirrhotics were followed routinely for the development of OHE. RESULTS: Cirrhotics performed worse than controls on SPT and ICT. Using SPT, 39 cirrhotics had MHE. ICT was administered faster than SPT (15 vs 37 min). Cirrhotics with MHE had significantly higher lure (28%vs 3%) and lower target response (91%vs 96%) compared with those without MHE. Lure/person >5 had 90% sensitivity/specificity for MHE diagnosis. AUC for receiver-operating characteristic for lures alone was 95.8%. Lure and target responses were highly correlated (r= 0.9) between sessions showing high test-retest reliability. Five (10%) patients developed OHE on f/u of 26 +/- 10 months; all five had been diagnosed with MHE using ICT and SPT. None of the five patients with discordant results on SPT and ICT developed OHE. CONCLUSIONS: ICT has good sensitivity/specificity for MHE diagnosis, is reliable and is equivalent to SPT for predicting OHE development.

Attention↗