Abstract
With the explosive use of personal computers or PCs, reducing computer energy consumption is paramount for sustainability. The display is the largest energy consumer in a personal computer. Current display energy management technologies ignore the attention of the PC user and therefore may either switch the display off when the user looks at the screen or lose energy by keeping the display on when nobody looks at it. This chapter discusses a new display energy management technology and outlines its implementation in a personal computer system. Unlike existing technologies, which “sense” a PC user through keyboard and/or mouse or the other sensors, this technology “watches” the user through a single camera or CMOS vision sensor. The technology tracks the user’s eyes, keeping display active only if the user looks at its screen. Otherwise, it dims the display down or even switches it off to save energy. The authors implemented the technology in software and hardware and present the results of their experimental evaluation.
TopThe first widely used adaptive display power management technology was introduced almost two decades ago with adoption of VESA’s Display Power Management Signaling Specification. The technology specifies one or more power states (e.g. standby, sustain, and off) that are intermediate between on and off, turning the display to low power state after a specified period of inactivity on mouse and/or keyboard. Over the years, many additions and revisions to this technology have occurred, including Advanced Configuration and Power Interface (ACPI, 2004), developed by HP, Intel, Microsoft, Phoenix, and Toshiba. The OS-based ACPI links the display brightness as well as inactivity intervals to application1.