pfstmo_fattal02 (1)

pfstmo_fattal02 [--alpha <val>] [--beta <val>] [--saturation <val>] [--noise <val>] [--verbose] [--help]

This command implements a tone mapping operator as described in:

Gradient Domain High Dynamic Range Compression R. Fattal, D. Lischinski, and M. Werman In ACM Transactions on Graphics, 2002.

With respect to the original paper, this program provides additional parameter which limits the amplification of noise. The noise is often starkly amplified because of division by zero in one of the equations in the paper. Extension contributed by Przemyslaw Bazarnik.

Results of this TMO can be improved by using a gamma correction.

--alpha <val>, -a <val>

Set alpha parameter. <val> defines the threshold gradient value (luminance differents of adjacent pixels) below which the gradients are amplified (detail enhancement) and above which the gradients are attenuated (global contrast reduction). Suggested range is 1 to 0.0001. It is reasonable to change parameters by orders of magnitude, so for instance trying 0.1, 0.01, 0.001 etc. (see paper for details).

--beta <val>, -b <val>

Set beta parameter. <val> sets the strength of gradient (local contrast) modification. Suggested range is 0.8 to 0.96 (see paper for details). Value of 1 does not change contrasts, values above 1 reverse the effect: global contrast is stretched and details are attenuated. Values below 0.5 lead to very strong amplification of small contrast, so consider using --noise parameter close to 'alpha' value to prevent noise.

--saturation <val>, -s <val>

Amount of color saturation. Suggested range is 0.4 to 0.8. Default value: 0.6.

--noise <val>, -n <val>

Reduces gradient amplification value for gradients close to 0 and reduces noise in the result. <val> defines gradient value (luminance differents of adjacent pixels) which is treated as noise. Suggested range is 0.0 to the value of alpha. Default value calculated based on alpha: 0.001*alpha.

--verbose

Print additional information during program execution.

--help

Print list of command line options.

pfsin memorial.hdr | pfstmo_fattal02 -v | pfsgamma -g 2.2 | pfsout memorial.png

Tone map image and save it in png format.

pfsin(1) pfsout(1) pfsview(1)

Please report bugs and comments on implementation to Grzegorz Krawczyk <[email protected]>.