CAD/Graphics 2013, Hong Kong An Image-space Energy-saving Visualization Scheme for OLED Displays Haidong Chen 1, Ji Wang 2, Weifeng Chen 3, Huamin Qu 4, Wei Chen 1 1 Zhejiang University, CHINA, 2 Virginia Tech, U.S., 3 Zhejiang University of Finance & Economics, CHINA, 4 Hong Kong University of Science and Technology, HONGKONG

2 Background CAD/Graphics 2013 Hong Kong LCD DisplayOLED Display High-intensity backlight Consume a constant energy Self-emissive Energy consumption is dependent on the shown content

3 Current Energy Reduction Techniques Device-level – Dynamic voltage scaling [Shin et al. 2011] Context-aware Dimming – Tracking user interactions and behaviors [Moshnyaga et al. 2005, Betts-LaCroix 2010] Color Remapping – Changing color [Chuang et al. 2009, Wang et al. 2012, Dong et al. 2012] CAD/Graphics 2013 Hong Kong Neglect the issue of perceptual quality loss Not feasible to many applications

4 Our Contributions An adaptive color dimming scheme – Energy reduction – Minimization of perceptual quality loss A GPU-friendly visual saliency computation algorithm CAD/Graphics 2013 Hong Kong

5 Two Observations Dimming remains an effective energy saving scheme Perceptual quality loss can be remedied by explicit highlighting visual salient features CAD/Graphics 2013 Hong Kong

6 Our Approach CAD/Graphics 2013 Hong Kong The pipeline of our approach

7 Our Approach Step1: Suppress undesired details (Abstraction) CAD/Graphics 2013 Hong Kong Solved with the bilateral grid data structure [Chen et al. 2007]

8 Our Approach Step2: Compute edge-oriented saliency map CAD/Graphics 2013 Hong Kong Visually salient feature detector: Saliency map: S (p) = (1− τ) M d (p) + τM c (p)

9 Our Approach Step3: Dimming CAD/Graphics 2013 Hong Kong Energy-saving result Input Abstracted Saliency map Dimming function: Preservation of details Global luminance

10 Experiments Measuring energy consumption model CAD/Graphics 2013 Hong Kong [Dong et al. 2012]

11 Experiments 3D volumetric data visualization α=0.65 β=0.75 CAD/Graphics 2013 Hong Kong OriginalSimulated uniform dimming 16.1% energy reduction Our result 17.9% energy reduction

12 Experiments 2D geo visualization α=0.75 β=0.5 CAD/Graphics 2013 Hong Kong OriginalOur result 642.2% energy reduction Simulated uniform dimming 63.7% energy reduction

13 Experiments Performance – Collected from a PC with NV GTX580, Intel Core2 Duo3.0GHz CPU, 4GB host memory CAD/Graphics 2013 Hong Kong

14 User Study 24 Participants – Age 22-29; 9 females, 15 males; 4 undergraduates, 20 graduate students CAD/Graphics 2013 Hong Kong

15 User Study Tasks – [T1] Visual Search Identify “street map” in the maps processed with three schemes (NC: normal color scheme; SGD: our saliency guided color scheme; UD: simulated uniform dimming scheme ) 8 participants for each scheme 2 trials for each participants CAD/Graphics 2013 Hong Kong Given street map

16 User Study Tasks – [T2] Preference Ranking Criterion: clarity, local contrast, blurriness, energy consumption Rank each image with 1st, 2nd, 3 rd CAD/Graphics 2013 Hong Kong

17 User Study Result analysis – Completion time CAD/Graphics 2013 Hong Kong

18 User Study Result analysis – Preference ranking for Geo-Vis application CAD/Graphics 2013 Hong Kong

19 User Study Result analysis – Preference ranking for volumetric data vis CAD/Graphics 2013 Hong Kong

20 Conclusions Introduce a novel saliency-guided color dimming scheme for OLED displays – simultaneous saving energy consumption and improving perceptual quality los issue A preliminary user study to testify the acceptance of our method CAD/Graphics 2013 Hong Kong

21 Acknowledgements This work is partially supported by the NSF of China ( ), the National High Technology Research and Development Program of China (2012AA12090), the Major Program of National Natural Science Foundation of China ( ), and the National Natural Science Foundation of China ( ). CAD/Graphics 2013 Hong Kong

22 Thanks CAD/Graphics 2013 Hong Kong OriginalSimulated uniform dimming 16.1% energy reduction Our result 17.9% energy reduction