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ppmflash - brighten a picture to approach white |
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ppmflash flashfactor [ppmfile] |
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This program is part of Netpbm(1). ppmflash reads a PPM image as input. It changes the color of each pixel to bring it a specified amount closer to white. It generates a PPM image of the result. flashfactor is a real number between 0 and 1, inclusive. ppmflash increases the intensity of each RGB component by the fraction flashfactor of the difference between the current value and full intensity. So if a pixel contains 60% full red, 10% full green, and no blue and you specify 0.5 (half), ppmflash increases the red to 80% (because it was 40% from full intensity, so it adds half of 40% to the original 60%), the green to 55%, and the blue to 50%. If flashfactor is zero, the output is identical to the input. If flashfactor is one, the output is all white. ppmbrighten does a more normal kind of brightening. pamfunc does a very simple brightening. Both ppmbrighten and pamfunc can reduce brightness as well. pnmgamma is another way people do a similar brightening, though it isn’t really intended for that. |
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ppmbrighten(1) pamfunc(1), pnmgamma(1), ppm(1), |
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Copyright (C) 1993 by Frank Neumann |