1. Perception Motivated Hybrid Approach to Tone Mapping Martin Čadík Czech Technical University in Prague, Czech Republic

2. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (2) Content HDR tone mapping Hybrid Approach Perceptually plausible approach Cognitive approach Conclusion

3. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (3) High Dynamic Range Imaging HDRI –useful in many areas of computer graphics and applications HDR images –several orders of magnitude –high precision [Reinhard et al. 05]

4. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (4) Tone Mapping Issue 10 -6 10 8 10 -6 10 8 Real world Ordinary picture Low Dynamic Range High Dynamic Range

5. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (5) Tone Mapping Goals Aesthetical Cognitive Perceptual [Cadik et al. 06]

6. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (6) Global and Local Methods Global methods (TRC) –fast –simple, easy to implement –good reproduction of overall image attributes (perceptual) Local methods (TMO) –spatial processing –time-consuming –good in reproduction of details (cognitive) –artifacts

7. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (7) Global and Local Methods [Ward94] [LCIS99]

8. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (8) Subjective Perceptual Experiments [Cadik et al. 06] –superiority of global methods for reproduction of natural scenes

9. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (9) Hybrid Approach to Tone Mapping

10. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (10) Hybrid Approach to Tone Mapping

11. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (11) Hybrid Approach to Tone Mapping

12. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (12) Hybrid Approach to Tone Mapping

13. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (13) Hybrid Approach to Tone Mapping

14. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (14) Enhancement Map map we use to guide local enhancement construction according to the aim of the method floating point values (blend of TRC and TMO) HDR LDR

15. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (15) Enhancement Map Benefits Reproduction of overall attributes –not affected by local method Lost details recovered Fast computation –local method applied to small portion of image

16. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (16) Perceptually Plausible Implementation [Ward 94]Bilateral filtering [Durand & Dorsey 02]

17. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (17) Transformations Global method Hybrid method Local method

20. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (20) Our Results

21. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (21) Our Results

22. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (22) Cognitive Approach [Ward et al. 97] + Trilateral filter [Choudhury & Tumblin 03] different construction of enhancement map details in the paper

23. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (23) Performance Results slight slowdown of original global approaches (we ‘pay’ a bit for the wanted details) speedup to the original local approaches (average results over 10 HDR images) Perceptually plausibleCognitive implementation Enhancement map [%of pixels] SpeedupEnhancement map [%of pixels] Speedup 1.4e-3%118.50.132%41.7

24. Perception Motivated Hybrid Approach to Tone Mapping, Martin Čadík, cadikm@fel.cvut.cz WSCG’07, Pilsen, Czech Republic, 31. 1.2007 (24) Conclusions General hybrid approach –utilization of existing methods –can be tailored to miscellaneous goals Global method (TRC) + local method (TMO) –general paradigm of perceptually plausible TMO design Enhancement map Fast, simple, scalable, perceptually plausible –suitable also for time-critical HDR applications

25. Perception Motivated Hybrid Approach to Tone Mapping Martin Čadík cadikm@fel.cvut.cz http://www.cgg.cvut.cz/~cadikm Thank You for Your Attention