Joe Kniss Warren A. Hunt Kristin Potter Pradeep Sen IStar: A Raster Representation for Scalable Image and Volume Data. 1424-1431 2007 13 IEEE Trans. Vis. Comput. Graph. 6 http://doi.ieeecomputersociety.org/10.1109/TVCG.2007.70572 db/journals/tvcg/tvcg13.html#KnissHPS07