HDRToneMap - the absolute range of environmental radiances...

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Unformatted text preview: the absolute range of environmental radiances is vast (> 8 log units) star light star light moon light moon light office light office light day light day light search light search light 10 10-6-6 10 10-2-2 10 10 1 10 10 2 10 10 4 10 10 8 10 10 the dynamic range of radiances in a scene can also be large (>4 log units) 10 10 star light star light moon light moon light office light office light day light day light search light search light 10 10-6-6 10 10-2-2 10 10 1 10 10 2 10 10 4 10 10 8 Shadows Highlights Shadows Highlights High Dynamic Range High Dynamic Range the absolute and dynamic range of display device is small (~1.5 - 2.0 log units) 0 255 0 255 Range of Typical Displays: Range of Typical Displays: from ~1 to ~100 cd/m 2 10 10 star light star light moon light moon light office light office light day light day light search light search light 10 10-6-6 10 10-2-2 10 10 1 10 10 2 10 10 4 10 10 8 Shadows Highlights Shadows Highlights High Dynamic Range High Dynamic Range How do we compress an HDR image so as to realistically display on a LDR display device? Image Source: Garettt Johnson, RIT Visual Adaptation Local Adaptation Multi-scale Adaptation log L TVI function 2 4 6-2-4-6-2 2 4 log L a L a + L L a Webers Law : L=kL a . Over a wide range of ambient light, L a , L is directly proportional to L . Psychophysical Studies log L log L a Sensitivity log Sensitivity 2 4 6-2-4-6 1 Visual Sensitivity = -------- L Sensitivity is inversely proportional to the adaptation luminance L L a . log L log L a Sensitivity rod cone log Sensitivity 2 4 6-2-4-6 1 Visual Sensitivity = -------- L Sensitivity is inversely proportional to the adaptation luminance L L a . Gain proportional to visual sensitivity....
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This note was uploaded on 08/22/2010 for the course CAP 6701 taught by Professor Staff during the Spring '10 term at University of Central Florida.

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HDRToneMap - the absolute range of environmental radiances...

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