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Because displays account for a large fraction of the power dissipation in smart watches, mobile phones, and tablets, it is important and interesting to develop techniques to reduce display power dissipation.

 

Crayon is a facility that can be inserted transparently into an operating system’s user interface pipeline, or applied offline to application assets. Crayon reduces display power dissipation when users accept trading display quality for longer battery life. Crayon works by exploiting three fundamental properties: The limited ability of humans to resolve small changes in shape and color, the image-content-dependence of the power dissipation of new display technologies such as DLP pico-projectors and OLED displays, and the low cost of computation relative to display power savings.

We have implemented and evaluated Crayon in  three contexts: a hardware platform with detailed power measurement facilities and an OLED display, an Android tablet, and a set of cross-platform tools. Our results show that Crayon’s color transforms can reduce display power dissipation by over 66% while producing images that remain visually acceptable to users. The measured whole-system power reduction is approximately 50%. We quantify the acceptability of Crayon’s shape and color transforms with a user study involving over 400 participants and over 21,000 image evaluations.

 

Status: This is an ongoing project. If you are interested in collaborating on some of the unsolved problems or applications, please get in touch!

Collaborations: This is joint work with Virginia Estellers (UCLA) and Martin Rinard (MIT).

 

Publications

  1. P. Stanley-Marbell, V. Estellers, and M. Rinard "Crayon: Saving Power through Shape and Color Approximation on Next-Generation Displays", In 11th Annual European Conference on Computer Systems,  (EuroSys'16), April 2016. [Download PDF]