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root/radiance/ray/src/cal/cal/sf.cal
Revision: 1.1
Committed: Sat Feb 22 02:07:21 2003 UTC (21 years, 2 months ago) by greg
Branch: MAIN
CVS Tags: rad5R2, rad4R2P2, rad5R0, rad5R1, rad3R7P2, rad3R7P1, rad4R2, rad4R1, rad4R0, rad3R5, rad3R6, rad3R6P1, rad3R8, rad3R9, rad4R2P1
Log Message:
Changes and check-in for 3.5 release
Includes new source files and modifications not recorded for many years
See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release

File Contents

# User Rev Content
1 greg 1.1 {
2     Calculation of contrast-based scalefactor
3    
4     8/17/93
5    
6     Input: ex = picture exposure
7     or: Lwa = world adaptation luminance
8     Output: sf = scalefactor for display
9     adj = corresponding exposure adjustment
10    
11     Optional Inputs: Ldmax = maximum display luminance
12     Lda = display adaptation luminance
13     }
14     Lwa = WE*.5/ex;
15     Ldmax = 120;
16     Lda = Ldmax/2;
17    
18     sf = ((1.219 + Lda^.4)/(1.219 + Lwa^.4))^2.5 / Ldmax;
19    
20     adj = WE*sf/ex;