This review focuses on low and intermediate stages of contour shape processing. It is split into two main sections, 'Contour Detection' and 'Shape Discrimination and Representation'. The first section examines contrast detection of elements within a contour ("collinear facilitation") and the detection of contours in noise ("contour integration"). The second section deals with the discrimination...

PURPOSE Previous retrospective studies have found that integration of orientation information along contours defined by Gabor patches is abnormal in strabismic, but not in anisometropic, amblyopia. This study was conducted to reexamine the question of whether anisometropic amblyopes have contour integration deficits prospectively in an untreated sample, to isolate the effects of the disease fro...

We examined the effects of spatial frequency similarity and dissimilarity on human contour integration under various conditions of uncertainty. Participants performed a temporal 2AFC contour detection task. Spatial frequency jitter up to 3.0 octaves was applied either to background elements, or to contour and background elements, or to none of both. Results converge on four major findings. (1) ...

Ratio Contour algorithm is recently introduced into the research about image segmentation. Several papers show that Ratio Contour has good performance on salient boundary detection, which can reach global optimization. This paper aims to solve hierarchical region-based segmentation by Ratio Contour algorithm. Two important problems should be addressed for this purpose: One is extending boundary...

We propose a biologically motivated method, called nonclassical receptive field (non-CRF) inhibition (more generally, surround inhibition or suppression), to improve contour detection in machine vision. Non-CRF inhibition is exhibited by 80% of the orientation-selective neurons in the primary visual cortex of monkeys and has been shown to influence human visual perception as well. Essentially, ...

Human observers are able to locate contours that are defined solely on the basis of long-range, orientation-domain correlations. The integrity of the mechanisms responsible for second-order contour detection is disrupted by amblyopia (Kovacs et al., 1996; Hess et al., 1997) and it is therefore of interest to develop methods for assessing pediatric patients undergoing treatment for amblyopia. In...

The problem of lip contour detection is critical in the lipreading systems based on contour processing. The typical contour detection strategy based on image segmentation in homogeneous regions fails in the case when the mouth images available for lipreading are lowcontrast gray level images. Most of the solutions adopted require manual marking of some contour points. Here we propose a new solu...

We propose a contour operator, called CORF, inspired by the properties of simple cells in visual cortex. It combines, by a weighted geometric mean, the blurred responses of difference-of-Gaussian operators that model cells in the lateral geniculate nucleus (LGN). An operator that has gained particular popularity as a computational model of a simple cell is based on a family of Gabor Functions (...

Medical images (X-ray, CT, MR or PET) of human organs are widely used in the everyday clinical praxis. The paper presents methods which allows the user to analyze, model and adjust the total knee contour detection procedure during a preoperative planning which eliminating the need of using expensive and sophisticated commercial software tools, which procedures are not familiar to the natural us...

In this paper, we present a novel object detection scheme using contour fragments. The template fragments are extracted by decomposing the template contour. The hinge angle, contour direction and partial Hausdorff distance (PHD) are used to match the fragments in the edge image. Then, the Multiclass Discriminative Field (MDF) is used to select the matches. With these selected matches and their ...