Supplementary Material for Our Paper

Multi-Class (Anisotropic) Electrostatic Halftoning


Multi-Class (Anisotropic) Electrostatic Halftoning
Tonemapping Operator for 8-bit Channels


This page contains our tonemapping operator for grey vales quantised to 8-bit depth, which is used to improve the visual appearance of dark image areas. Thereby, u(x) denotes a grey-value in the range [0,1], c the number fulfilling Equation (5) and (6) in our paper, and T(u(x)) the grey value after tonemapping was applied. For grey values in the range [0,255], the mapping from 255 · u(x) to 255 · T(u(x)) should be used.


u(x) 255 ·u(x) c 255 ·T(u(x)) T(u(x))
0.000000 0.0000 0.866025 -53.3459 -0.209200
0.003922 1.0000 0.893535 -34.6518 -0.135890
0.007843 2.0000 0.905129 -27.2789 -0.106976
0.011765 3.0000 0.914085 -21.7746 -0.085391
0.015686 4.0000 0.921665 -17.2408 -0.067611
0.019608 5.0000 0.928358 -13.3295 -0.052273
0.023529 6.0000 0.934415 -9.8621 -0.038675
0.027451 7.0000 0.939984 -6.7330 -0.026404
0.031373 8.0000 0.945163 -3.8726 -0.015186
0.035294 9.0000 0.950017 -1.2340 -0.004839
0.039216 10.0000 0.954596 1.2184 0.004778
0.043137 11.0000 0.958935 3.5098 0.013764
0.047059 12.0000 0.963063 5.6611 0.022200
0.050980 13.0000 0.967000 7.6873 0.030146
0.054902 14.0000 0.970765 9.6019 0.037654
0.058824 15.0000 0.974370 11.4144 0.044762
0.062745 16.0000 0.977827 13.1337 0.051505
0.066667 17.0000 0.981144 14.7663 0.057907
0.070588 18.0000 0.984327 16.3175 0.063990
0.074510 19.0000 0.987380 17.7912 0.069769
0.078431 20.0000 0.990305 19.1904 0.075256
0.082353 21.0000 0.993102 20.5168 0.080458
0.086275 22.0000 0.995763 21.7684 0.085366
0.090196 23.0000 0.998274 22.9402 0.089962
0.094118 24.0000 n/a 24.0000 0.094118

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