Study Of The Shape-Based Graphics Retrieval System And Its Application In Education

The graphics is a kind of specially image, which main body is composed of the outside contour and the inside region, with the single background color, and shape is its major visual feature. In educational field, the graphics resources are richer and richer and used extensively, so the effectively retrieval of graph becomes especially important. The shape-based graphics retrieval system retrieves graphics by shape feature's similarity. With the purpose of helping the education workers in graphics retrieval, this thesis studied the shape analysis and retrieval technology of graphics and built a shape-based graphics retrieval system applied in education.Mainly by document investigation and experimentation, the thesis carried out a deeper research in shape feature analysis and shape-based graphics retrieval technology. The main jobs, achievement and conclusion are as follows:Firstly, we summarized description parameters of shape feature and realized many kinds of description parameters of shape feature, including invariant moments, Zernike moments, edge orientation histogram, rectangularity, circularity, eccentricity, contour curvature histogram, interior angles histogram fourier descriptors.Secondly, we realized the shape-based graphics retrieval system, which forms by four modules, including the module of generating feature index database, the module of inputting by user, the module of system retrieval, the module of outputting. The user submits the query graphics through the query interface, and then the system extracts its shape feature after processing the query graphics and shape feature from the feature index database, calculating their similarity. The system sorts and filters them by similarity, and then the results are showed to the user.Thirdly, we compared many shape feature effect in the graphics retrieval by way of the experiment of MPEG-7 Shape B library. Zernike moments are the best in the retrieval performance, edge orientation histogram and invariant moments are better, rectangularity, eccentricity and circularity are very bad. On this conclusion foundation, we proposed the comprehensive retrieval method which is better then all.Fourthly, shape-based graphics retrieval system's application in the education embodied in mainly in the establishment and retrieval of the educational graphics library. We built an educational graphics library which contains more than 6000 graphics, including teaching picture, animals, plants, supplies and natural, etc. The educational graphics library contains 165 classes, selecting ten per class to form the graphics sample library. We used the comprehensive retrieval method to retrieval the two libraries, the effect of retrieval decreased owing to a large number of increases of graphics class and quantity at the same time. The experiment indicates that simply shape-based graphics retrieval's effect is satisfied under the circumstances of about 1000 graphics, so it is fit for the retrieval in special subject retrieval. If it is the large-scale library retrieval, it needs to combine with other feature.Using the program development tool of Visual C++ 6.0, based on Windows XP OS and Microsoft Access 2003 database, we developed the shape-based graphics retrieval system and did experiment on several graphics libraries, which got satisfied result and implied in education. Moreover, we perfected some functions under the menus of graphics processing and shape description in the system of digital image analysis and processing, and added many functions of extracting shape feature programmer.The research indicates that the shape-based graphics retrieval system using the comprehensive method gains good retrieval effect, and it riches education graphics resources, providing a new way for teachers and students to retrieval education graphics. The research on the shape analysis and retrieval technology of graphics is elementary, but we hope more and more people pay attention to technology application in education.