Backlight dimming in power-aware mobile displays

This paper presents a temporally-aware backlight scaling (TABS) technique for video streams. The goal is to maximize energy saving in the display system by means of dynamic backlight dimming subject to a user-specified tolerance on the video distortion. The video distortion itself comprises of (i) an intra-frame (spatial) distortion component due to frame-sensitive backlight scaling and transmittance function tuning and (ii) an inter-frame (temporal) distortion component due to large-step backlight dimming across multiple frames and modulated by the physiological characteristics of the human visual system. The proposed backlight scaling technique is capable of efficiently computing the flickering effect online and subsequently using a measure of the temporal distortion to appropriately adjust the slack on the intra-frame spatial distortion. The proposed technique has been implemented on the Apollo Testbed II hardware platform. Actual current measurements on this platform demonstrate the superiority of TABS compared to previous backlight dimming techniques.