1. 64-bits of Glorious Light An Introduction to HDRR CSE3AGT - Paul Taylor 2010

2. HDRR vs LDRR http://upload.wikimedia.org/wikipedia/comm ons/1/1d/Farcryhdr.jpg

3. We are going to look at Colour a little differently... Red Green Blue Luminosity Chromaticity r and b

4. Luminosity http://www.cambridg eincolour.com/tutorial s/color-space- conversion.htm

5. CIELUV and CIEXYZ L u v – L is the Luminance – u and v are the Chromaticity X Y Z ( also known as tristimulus values) These are the amounts of each of the primaries needed for an observer to see the desired colour Y is the Luminance Normalised it becomes CIExyz x = X / (X + Y + Z) y = Y / (X + Y + Z) z = Z / (X + Y + Z) = 1 - (x + y)

6. http://software.intel.com/si tes/products/documentatio n/hpc/ipp/ippi/ippi_ch6/ch 6_color_models.html

7. An XYZ graph

8. Why are we going to do this? http://en.wikipedia.org/wiki/YCbCr

9. RGB and sRGB RGB is Gamma independant Range [0,1] sRGB utilises a Gamma of 2.2 and a D65 Whitepoint

10. Colour Format Factors Lab Gamut Efficiency -% of visible colours represented Coding Efficiency -% of data space that represents real colours (waste)

11. The Lab Gamut

12. RGB Colour Spaces http://www.brucelindbloom.com/index.html?WorkingSpaceInfo.htm l#Specifications

13. Adobe RGB

14. sRGB

15. NTSC RGB

16. PAL / SECAM RGB

18. sRGB to XYZ http://www.brucelindbloom.com/index.html?Eq n_RGB_XYZ_Matrix.html#WSMatrices sRGB->XYZXYZ->sRGB

19. XYZ to Luv D65 = X r =95.04, Y r =100.00, Z r =108.88 http://www.brucelindbloom.com/in dex.html?Eqn_RGB_XYZ_Matrix.htm l#WSMatrices

20. Luminance http://colorusage.arc.nasa.gov/lum_and_chrom.php Light of an equal power, but different wavelength does not appear equally bright to the viewing eye.

21. Chromaticity Chromaticity r and g from a CIE RGB source: http://en.wikipedia.org/wiki/CIE_1931_color_space#Definition_of_the_CIE_XYZ_color_spa ce

22. U’ and v’

23. http://www.nikon.com/about/fee lnikon/light/chap03/sec01.htm

24. Why are we doing this? http://en.wikipedia.org/wiki/YCbCr

25. HDRR vs LDRR http://upload.wikimedia.org/wikipedia/comm ons/1/1d/Farcryhdr.jpg

26. HDRR vs LDRR http://upload.wikimedia.org/wikipedia/comm ons/1/1d/Farcryhdr.jpg

27. Y Cb Cr (YCC) What is it? – A Colour Format yes – Y is the luma – Chroma Blue – Chroma Red Y’CbCr has a non-linear luma (Gamma encoded)

28. http://en.wikipedia.org/wiki/YCbCr

29. CIE Chromacity Diagram http://en.wikipedia.org/wiki/File:CIExy1931.svg

30. Using all this to create HDRR

31. Emulating Light Our Contrast adaption is an adjustment of the iris, a relatively slow chemical change Dynamic Contrast of the eye is 1,000,000 : 1 Static Contrast of the sys is 10,000 : 1

32. Light Blooming When Light scatters in the Lens of your Eye The brain interprets this as a bright spot. – This has the effect of really bright stuff bleeding over the edges of other objects. Emulating this bleeding makes the player think the white spot is insanely bright!

33. Lens Flare This is the diffraction of light in the lens of your eye It results in rays of light emanating from small light sources, and possible chromatic effects. We have been emulating this effect for a long time, but with HDRR can also include the bleeding / distortion in relating to world objects

34. Screen Effects (Not all HDRR) Depth blur (Near and Far) Motion Blur Full Screen Bloom Material Bloom Cross fading (Cinematic) Screen Distortions (Various) – Heat Haze – Colour Filters (Night Vision) HDRR effects!!

35. Tone Mapping This is us trying to jam 1,000,000 : 1 contrast ratio onto a screen which may have only 5,000 : 1 ratio.

36. Luv / XYZ benefits Light Mixing Two lights A and B All possible outputs lie directly between the two points

37. LogLuv Encoding LogLuv is a great format for punching down the size of LUV encoded data into variables such as Int8’s or similar smaller data sizes

38. HDR Teapot

39. References http://www.xnainfo.com/content.php?conten t=28 http://www.xnainfo.com/content.php?conten t=28 http://www.absoluteastronomy.com/topics/F ull_screen_effect http://www.absoluteastronomy.com/topics/F ull_screen_effect http://www.absoluteastronomy.com/topics/Hi gh_dynamic_range_rendering http://www.absoluteastronomy.com/topics/Hi gh_dynamic_range_rendering