ppmnorm

Normalize image contrast

$ ppmnorm [input.ppm] > [output.ppm]

$ ppmnorm -bpercent [2] -wpercent [1] [input.ppm] > [output.ppm]

ppmnorm [options] [file]

ppmnorm normalizes the contrast of a PPM image by stretching its color histogram to use the full available range. Dark images are brightened and washed-out images gain contrast, making it a quick automatic enhancement tool.
The black and white percentile parameters control how aggressively the ends of the histogram are clipped before stretching, preventing outlier pixels from limiting the enhancement. This is an alias for pnmnorm operating in color mode. Part of the Netpbm toolkit.

FILE

Input PPM file.

Black percentage.

White percentage.

Black cutoff value.

White cutoff value.

Alias for pnmnorm with color. Part of Netpbm suite.

ppmnorm was created as part of Netpbm for color image normalization.

pnmnorm(1), ppmgamma(1), ppm(5)