Scope - quality retaining display rendering workload scaling based on user-smartphone distance

Modern smartphone display system come equipped with powerful GPU's capable of rendering advanced 2D and 3D graphics. These GPU's make up a significant portion of the system power profile due to the high resolution and framerate of smartphone display. These display features are selected during the design phase of a smartphone and correspond to the capabilities of the human visual system (HVS). However, the level of detail observable by the HVS is not static and changes with user-smartphone distance. In this paper we propose Scope, a system which alters the rendering resolution and framerate on a smartphone to scale display rendering workload in response to real time changes in user-smartphone distance. We demonstrate a new method of measuring this distance in real-time which is able to minimize front-facing camera sampling through the use of sensor fusion techniques. The result is that Scope requires a power overhead of only 20mW on average as the front-facing camera need only be sampled 4 times per minute. We demonstrate that Scope is able to reduce smartphone power consumption up to 58% while retaining visual quality in most cases.