A new boundary contour extraction algorithm based on curve evolution model and ant colony algorithm is proposed in this paper. Firstly, ant colony algorithm is used to find the optima of snake points for rapidly converging near image edge. Then the interpolation algorithm is applied to gaining the object’s rough contour that is used as the initial zero level set. The accurate contour can be obt...

There is an accelerated resorption in the first six months after the extraction of the dental element, both horizontally and vertically. These clinical changes normally undertake the aesthetic result of prosthetic rehabilitation, and implant installation after the extraction can be a resource to decrease resorption. The clinical case described in this paper demonstrates a sequence of clinical a...

Topological techniques provide robust tools for data analysis. They are used, for example, for feature extraction, for data de-noising, and for comparison of data sets. This chapter concerns contour trees, a topological descriptor that records the connectivity of the isosurfaces of scalar functions. These trees are fundamental to analysis and visualization of physical phenomena modeled by real-...

The contour line is one of the most important features of 2D scalar field in scientific visualization. A new method for contour line extraction is presented in this paper. Unlike the existing methods, the contour line is extracted in image space. In order to accelerate root-finding procedure, Bezier clipping and subdivision algorithm are used in the proposed method. Cross scan-line algorithm is...

In this thesis, I show how to use the topological information encoded in an abstraction called the contour tree to enable interactive manipulation of individual contour surfaces in an isosurface scene, using an interface called the flexible isosurface. Underpinning this interface are several improvements and extensions to existing work on the contour tree. The first, and most critical, extensio...

In this thesis, I show how to use the topological information encoded in an abstraction called the contour tree to enable interactive manipulation of individual contour surfaces in an isosurface scene, using an interface called the flexible isosurface. Underpinning this interface are several improvements and extensions to existing work on the contour tree. The first, and most critical, extensio...

This paper describes a novel algorithm for exact eye contour detection in frontal face image. The exact eye shape is a useful piece of input information for applications like facial expression recognition, feature-based face recognition and face modelling. In contrast to well-known eye-segmentation methods, we do not rely on deformable models or image luminance gradient (edge) map. The eye wind...

An extension of second-order diierential edge detection methods to color images was previously proposed. This work shows how, by casting the problem into a subpixel resolution oriented framework, an eecient algorithm for edge detection and contour traversal can be devised for both graylevel and color images. The results from an implementation on a standard PC show that the computational cost is...

This paper describes a computationally efficient method for estimating the predominant pitch in audio recordings. The proposed method is intended for building a contentbased indexing and retrieval system that can search in a audio database using the melody line of a complex input audio sample. Available pitch estimation methods are effective primarily when dealing with recordings of human voice...

This work describes a novel methodology for automatic contour extraction from 2D images of 3D neurons (e.g. camera lucida images and other types of 2D microscopy). Most contour-based shape analysis methods cannot be used to characterize such cells because of overlaps between neuronal processes. The proposed framework is specifically aimed at the problem of contour following even in presence of ...