Exploiting Content Variation and Perception in Power-Aware 3D Graphics Rendering

• Authors: Jeongseon Euh;Wayne Burleson
• Venue: PACS '00 Proceedings of the First International Workshop on Power-Aware Computer Systems-Revised Papers
• Year: 2000

Real-time 3D graphics will be a major power consumer in future portable embedded systems. 3D graphics is characterized by intensive floating point calculations, heavy data traffic between memory and peripherals, and a high degree of non-uniformity due to content variation. Although 3D graphics is currently very limited in power-constrained environments, future user interfaces (head-mounted virtual reality) and applications (simulators, collaboration environments, etc.) will require power-aware implementations. Fortunately, we can exploit content variation and human perception to significantly reduce the power consumption of many aspects of 3D graphic rendering. In this paper we study the impact on power consumption of novel adaptive shading algorithms (both Gouraud and Phong) which consider both the graphics content (e.g. motion, scene change) and the perception of the user. Novel dynamically configurable architectures are proposed to efficiently implement the adaptive algorithms in power-aware systems with gracefully degradable quality. This paper introduces an integrated algorithm and hardware solution based on human visual perceptual characteristics and dynamically re-configurable hardware. Three approaches are explored which are both based on human vision and loosely analogous to video coding techniques. The first approach is called distributed computation over frames and exploits the after image phenomenon of the human visual system. The second approach exploits visual sensitivity to motion. According to the speed and distance from camera to object, either the Gouraud or Phong shading algorithm is selected. The third approach is an adaptive computation of the specular term computation used in Phong. Using the same selection criteria as in adaptive shading, a reduced computational cost algorithm is used for fast moving objects. Results based on simulation indicate a power savings of up to 85% using short but realistic rendering sequences. Future work includes: 1) more sophisticated architectures to support dynamic reconfiguration, 2)exploring other steps in the 3D graphics pipeline, and 3) extending these ideas to other multimedia applications which involve variable content, computation and human perception (for example, video and audio coding).