1. 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. 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. 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. 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. 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. 6 Our Approach CAD/Graphics 2013 Hong Kong The pipeline of our approach

7. 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. 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. 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. 10 Experiments Measuring energy consumption model CAD/Graphics 2013 Hong Kong [Dong et al. 2012]

11. 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. 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. 13 Experiments Performance – Collected from a PC with NV GTX580, Intel Core2 Duo3.0GHz CPU, 4GB host memory CAD/Graphics 2013 Hong Kong

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

15. 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. 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. 17 User Study Result analysis – Completion time CAD/Graphics 2013 Hong Kong

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

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

20. 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. 21 Acknowledgements This work is partially supported by the NSF of China (61003193), the National High Technology Research and Development Program of China (2012AA12090), the Major Program of National Natural Science Foundation of China (61232012), and the National Natural Science Foundation of China (81172124). CAD/Graphics 2013 Hong Kong

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