Low-overhead adaptive constrast enhancement and power reduction for OLEDs

Organic Light Emitting Diode (OLED) display panels are becoming increasingly popular especially in mobile devices; one of the key characteristics of these panels is that their power consumption strongly depends on the displayed image. In this paper, we propose a new methodology to reduce the energy consumed by OLED displays that relies on image-specific pixel-by-pixel transformations, aimed at preserving the contrast of the image as much as possible while reducing the overall power. Unlike previous approaches, our method focuses specifically on the minimization of time and power overheads to implement the image transformation at runtime. To this end, we propose a transformation that can be executed online in real time, either in software, with low time overhead, or in a hardware accelerator with a small silicon footprint. Despite the great reduction in complexity, our results are comparable to those achieved with more complex approaches in terms of image quality. Moreover, our method allows to easily explore the full quality-versus-power tradeoff by acting on a few basic parameters; thus, it enables the runtime selection among multiple display quality settings, according to the status of the system.