Four kinds of topological operations suitable for sculptured feature descriptions, i.

So feature description and extraction of shape is the main content of this topic.

To deal with the matching of 3D terrains which involves similar transformations of scale,rotation,and shift,a terrain contour matching approach based on the invariant feature description of a 3D terrain is proposed.

From the angle of manufacturing, this paper proposes a kind of feature taxonomy approach based\|on feature families, discusses several problems derived from comprehension difference to the concept of feature between the stage of modeling and recognition, and introduces the corresponding feature representation method, which meet sufficiently the demand of the different stages of product life ci.

According to the conception of color run-length, a method of feature representation based on run-length matrix for color image was proposed,then two similarity criterions were given.

This paper presents a feature model based on boundary represent(Brep), construct solid geometry(CSG) and feature describing graph(FDG), which gets over the history-based order of traditional feature modeling and which is a technology of history-independent and history-independent feature modeling.

Firstly,SIFT keypoints of realtime images and reference images were extracted efficiently using improved SIFT feature descriptor.

The principle of SIFT method is researched,then an improved SIFT points feature descriptor is proposed,aiming to the problem of its high dimension and complexity.

This paper introduces the definition of the content-based image retrieval and the visual description tools of MPEG-7,and analyzes the application of the feature descriptor.