Accelerated Unsteady Flow Line Integral Convolution
(IEEE Transactions on Visualization and Computer Graphics, Vol. 11, No. 2, March / April, 2005, pp. 113-125)
Zhanping  Liu
Robert J. Moorhead II
Abstract: Unsteady flow line integral convolution (UFLIC) is a texture synthesis technique for visualizing unsteady flows with high temporal-spatial coherence. Unfortunately UFLIC requires considerable time to generate each frame due to the huge amount of pathline integration that is computed for particle value scattering. This paper presents Accelerated UFLIC (AUFLIC) for near interactive (1 frame/second) visualization with 160,000 particles per frame. AUFLIC reuses pathlines in the value scattering process to reduce computationally expensive pathline integration. A flow-driven seeding strategy is employed to distribute seeds such that only a few of them need pathline integration while most seeds are placed along the pathlines advected at earlier times by other seeds upstream and therefore the known pathlines can be reused for fast value scattering. To maintain a dense scattering coverage to convey high temporal-spatial coherence while keeping the expense of pathline integration low, a dynamic seeding controller is designed to decide whether to advect, copy, or reuse a pathline. At a negligible memory cost, AUFLIC is 9* times faster than UFLIC with comparable image quality.
Index Terms: Flow visualization, vector field visualization, line integral convolution, unsteady flows, UFLIC, texture synthesis, image convolution, acceleration.

8.60X speedup was obtained for a 576x291 time-varying flow ( 41 time steps) and
9.45X speedup was obtained for a 397x397 time-varying flow (101 time steps)
on an SGI Onyx2 with four 400MHZ MIPS R12000 processors and 4GB memory.
13.05X speedup was obtained for the former flow and
14.13X speedup was obtained for the latter flow
on an HP-Compaq Presario laptop with a single Intel Celeron 1.6GHz CPU and 512MB SDRAM memory (Windows XP Home).


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