FujiFilm FN-PS551 Service Manual page 416

Appendix Chapter 2. Service Utility-Additional Instructions
1. Supplementary Explanation for Setting LUT Content
1.1 Summary of BAR (Basic curve ARranging) Tone Correction
With BAR tone correction, its gamma table (reference gamma curve, gamma tables No. 1 to 20) represents
a relationship between input QL (quantum level) and output QL. The QL is image data that represents
the density per pixel, and is denoted by a 10-bits digital value (integer value from 0 to 1023).
Note that the gamma table is represented by a density value in the gamma table file, but it is processed as
a QL value within the equipment.
Output QL
1023
Input/Output Relationship in the Gamma Table (BAR Scheme)
With BAR tone correction, the overall gamma curve is adjusted and varied by tweaking the density or
contrast of the reference gamma curve.
Density Adjustment
Adjust the overall density of the reference gamma curve by varying the Max. density parameter value.
The gamma curve is increased or decreased in the output QL direction according to the value of Max.
density.
The Max. density input range is from 0 to 100 (unit: %). With Max. density = 100, the gamma curve is
equal to the reference gamma curve; decreasing the value of Max. density lowers the overall density.
Note that the density cannot be increased greater than the reference gamma curve.
Output QL
0
Density Adjustment (BAR Scheme)
006-251-00
10.30.98 FM2327
0
1023
Reference gamma curve
Input QL
FP4G0201.EPS
Decreasing Max. density
lowers the output QL.
Input Q L
FP4G0202.EPS
FN-PS551 Service Manual
Appendix-19
Appendix-19