Research On Streamline Compression Method Of Large-scale Vector Field

Streamline plays an important role in analyzing complex fow phenomena and discovering fow laws.It is one of the most commonly used visualization methods to describe fow feld data.Currently,with the increase in data scale,the accurate storage of streamlines requires a large amount of storage space.How to store streamlines efciently is an urgent problem to be solved.Compressing streamline data can reduce the occupation of storage space and is an efective solution.However,the existing compression methods have obvious shortcomings,such as low compression ratio,the compression error is hard to control,intersections may accur after compression,etc.To solve these problems,we carrie out a series of related studies.The main works are as follows.1.Aiming at the problem of low compression ratio of the existing method,we proposed two hybrid compression methods based on spline curves.The frst one is called Incremental Piecewise Bézier Curve Hybrid Compression Method.After ftting the streamlines with piecewise B ézier curves,the control points are obtained and then compress them losslessly.The second one is called Piecewise B-spline Curve Hybrid Compression Method.B-spline curves with diferent number of control points are used to ft the streamlines,and then the control points and knot vectors are stored in a specifc format and compressed losslessly to obtain the compression results.The experimental results show that compared with the existing methods,the two methods proposed this paper have signifcantly improved the compression ratio,and the error can be strictly controlled by executing only once.2.Aiming at the problem that streamlines may intersect with each other after existing compressing,a streamline compression method maintaining topological relation is proposed in this paper,which introduces intersection tests in the compression process and adjusts error bound adaptively to avoid the intersections of compressed streamlines.To improve the efciency of intersection tests,we designed an intersection test acceleration algorithm based on bounding box technology.The experimental results show that our method can obtain compressed streamlines that are not intersected,and the compression ratio is still higher than the existing methods.3.Based on the above works,a streamline visualization and compression software BZip View is designed and developed,which has the functions of streamline generation,streamline visualization,streamline compression and so on.It has GUI(graphical user interface)interface for users’ convenience.