Differential coding scheme for efficient parallel image composition on a PC cluster system

摘要

Although the sort-last parallel rendering is a promising approach to accelerate large-scale computer graphics applications handling huge data sets, parallel image composition is a bottleneck of performance improvement. So far, several image coding schemes have been proposed in order to achieve fast image composition by compressing communicated data. These schemes mainly encode blank pixels in rendered images, which are pixels with no projection of objects. However, sufficient compression was not available in the case that rendered images have few blank pixels. This paper presents an image coding scheme that reduces the communication time in parallel image composition by effective compression of non-blank pixels and load balancing. The coding scheme exploits coherence of differential pixel values with a few additional computations that do not spoil the reduction in communication time. Experiments on a PC cluster with eight processing elements connected by a 100 Mbit Ethernet switching hub show that the worst frame rate of all viewing parameters can greatly be improved by the proposed coding scheme.