Fast Remote Isosurface Visualization With Chessboarding

Abstract

Isosurface rendering is a technique for viewing and understanding many large data sets from both science and engineering. With the advent of multi-gigabit-per-second network backbones such as Internet2 and fast local networking technology, scientists are looking at new ways to share and explore large data sets remotely. Telemedicine, which encompasses both videoconferencing and remote visualization is likely to be in widespread use with these advances. Despite the availability of increased bandwidth, two challenges remain. First, the time it takes to locate cells intersecting an isosurface of interest must be reduced for large data sets; a cell extraction technique that scales with data size is also critical. The second challenge has to do with the mitigating the effects of network latency on the overall isosurface visualization time. We present a remote isosurface visualization technique that addresses these two challenges. Isosurface extraction delays are reduced through the use of a search-optimized, chessboarded interval tree data structure on the disk. Network transport delays are reduced by sending cells extracted from the chessboarded data on the server, compressing it by about 87%. In addition, network transport delays are hidden effectively by overlapping data transport with server side functions. On a 100 Mbits/sec. switched LAN, the remote visualization time - the time between the issue of a query from the client side to the server and the displaying of a complete image on the client is only a few seconds for most isovalues in the well-known visible woman data set.