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In this paper, a simple, robust algorithm is proposed for detection crest lines on triangular meshes with noise. We update principal curvature when computing it on noisy models, and use two thresholds to remove unessential ridge and ravine points to guarantee that ridge and ravine points are perceptually salient points. Experimental results demonstrate our algorithm is effective.
Coded structured light is an effective technique to acquiring shape in stereovision. Coding strategy is one of the core techniques because it effects the measure precision and efficiency directly. There are two major group of techniques in color structured light encoding. One is to define coloured multi-slit, which is suitable for locating intensity peaks in the image. The other is to define coloured...
According to the differences in algae cells' shapes, various watershed algorithms are used to adaptively segment the algae cell images. Considering the noises' characteristics in these images, a new method is introduced in this paper. The basic idea is to segment the algae images, collected at scene, before denoising. The result shows that this algorithm can extract edges and inside details effectively...
This paper presents a novel method for recognizing objects using corner features. As one of the most important local features, corner contains lots of information with the shape of the objects. Our approach detects corner points from images and describes the objects based on them. The features are highly distinctive, in the sense that a single feature can be correctly matched with high probability...
Three dimensional (3D) visualization of anatomy plays an important role in image guided orthopedic surgery and ultimately motivates minimally invasive procedures. However, direct 3D imaging modalities such as Computed Tomography (CT) are restricted to a minority of complex orthopedic procedures. Thus the diagnostics and planning of many interventions still rely on two dimensional (2D) radiographic...
IC wafer image is composed of basic shape, mainly including lines, rectangles, rounds and ellipses. Firstly, this paper analyzes the shape of IC circuit image by the geometry of basic shape. When the images are moved and rotated, the moment has the same feature. Therefore, we can calculate the moment, the barycentric coordinate points and barycentric moment which are invariant in the same image. Secondly,...
This paper proposes improvement for the detection method for carotid artery calcification in dental panoramic radiographs. The existence of the carotid artery calcification as an index for arteriosclerosis attracts a great deal of attention. The detection method for carotid artery calcification has been proposed. However the detection rate is about 50% for real data and its improvement should be required...
An efficient method for rapidly detecting circles using edge-tracking and evidence-collecting is presented. First, edge points are tracked to form series of edge chains. Then three points are randomly selected from each edge chain to obtain a possible circle. In the end, an evidence-collecting process is applied to determine whether the possible circle is a true one or not. During the evidence-collecting...
In this paper, we focus on the problem of shape retrieval. A novel approach, called improved graph transduction, is proposed. As preceding graph transduction method, we regard the shape as a node in a graph and the similarity of shapes is represented by the edge of the graph. Then we learn a new distance measure between the query shape and the testing shapes. The main contribution of our work is to...
An optimization technique is proposed for the outline capture of planar images. The overall technique has various phases including extracting outlines of images, detecting corner points from the detected outline, and curve fitting. The idea of multilevel coordinate search has been used to optimize the shape parameters in the description of the generalized conic spline introduced. The spline method...
An optimization technique is proposed for the outline capture of planar images. The overall technique has various phases including extracting outlines of images, detecting corner points from the detected outline, and curve fitting. Linear and conic interpolation methods have been used for vectorization. The idea of multilevel coordinate search has been used to optimize the shape parameters in the...
Image contours, obtained by edge detection algorithms, provide a sparse but informative structural representation of image content. However, contours from edge detectors are typically incomplete. Delaunay triangulation of image contour points establishes proximity-based regional bindings of contour elements and supports perceptually meaningful completions of contours for image segmentation. Further,...
High precision identification of feature points is an important technology and one of the bases of computer vision, image analysis and image processing. In the practical applications, the feature points can not be identified easily in various conditions of light illumination, visual angle, texture, and perspective projection. And in many cases, the size of feature point is small, the context is uncertain...
Snakes, or active contours, are one of the major paradigms in image segmentation. With the gradient vector flow (GVF) as external force, they have a larger capture range and the ability to progress into concave boundaries. However, when we have to deal with highly non-convex shapes, the GVF field forms an area where the forces point in opposite directions and the snake stops. GVF is built as a diffusion...
This paper presents a new image segmentation framework which employs a shape prior in the form of an edge strength function to introduce a higher-level influence on the segmentation process. We formulate segmentation as the minimization of three coupled functionals, respectively, defining three processes: prior-guided segmentation, shape feature extraction and local deformation estimation. Particularly,...
In this paper we propose a novel computational method to infer visual saliency in images. The computational method is based on the idea that salient objects should have local characteristics that are different than the rest of the scene, being edges, color or shape, and that these characteristics can be combined to infer global information. The proposed approach is fast, does not require any learning...
A non parametric method that defines a pixel neighborhood within catadioptric images is presented in this paper. It is based on an accurate modeling of the mirror shape by using polarization imaging. Unlike the most of current processing methods in the literature, this method is non-parametric and can deal with the deformation of catadioptric images. This paper demonstrates how an appropriate neighborhood...
A new and fast method for dominant point detection and polygonal representation of a discrete curve is proposed. Starting from results of discrete geometry, the notion of maximal blurred segment of width v has been proposed, well adapted to possibly noisy and/or not connected curves. For a given width, the dominant points of a curve C are deduced from the sequence of maximal blurred segments of C...
The first step in lip-reading applications is mouth contour extraction to provide a link between the lip shape and the oral message. In our approach, lip contours are detected in the first image with the two algorithms developed and for static images. On subsequent images of the sequence, several key points (mouth corners, inner and outer middle contour points) are tracked with the Lucas-Kanade method...
Describing local patches to register image keypoints is an important task for building a huge database from video frames. When searching for an efficient descriptor, task is twofold: features must describe the featuring patches at a high efficiency, while the dimensionality should be kept at a manageable low value. The main assumption in finding local descriptors is the defect of continuity in the...
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