Semi-automatic generation of transfer functions for direct volume rendering
Gordon Kindlmann, James W. Durkin · 1998
Mthough dir~t volume rendering is a poweti tool for visutig complex structures within volume @ tie S* and mmplexity of the p-eter space controtig the rendering proms mb generating an Mormative rendering chtienging.k partic~, the specificadon of the transfer fiction -the mapping from data values to renderable optical properties -is frequently a time-consuming and unintuhive task IHy, the data beiig *u-shotid itsek suggest an appropriate transfer fiction that brings out the features of interest without obscuring them with elemen~of Etie importance.\\re demonstrate that this is possible for a kge class of scalar volume d~nmnely tit where the regions of interest are the boundties between different matenrds.A transfer function which makes boundaries reatiy \=lble can be generated from the reMonship between tiee quantitie~the data xdue and its first and second directioti derivatives ~ong the gradient direction.A data structure we term the Frwgrm vo& capwes the rektionship between these quantities tioughout the volume in a position independent computationMy efficient fashiom We describe the tbeoretid intportance of tie quantities measured by the histogram volume, the implementation issues in its cahxdation, and a method for semiautomatic transfer function generation through its anrdysis.We conclude with restits of the method on both id-synthetic data as we~as r~world &tase@.