Linux command
ppmnorm 命令
文本
涉及管道、覆盖或删除，执行前请先确认路径和参数。
常用示例
Normalize image contrast
ppmnorm [input.ppm] > [output.ppm]
Specify percentile range
ppmnorm -bpercent [2] -wpercent [1] [input.ppm] > [output.ppm]
说明
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.
参数
- -bpercent _N_
- Black percentage.
- -wpercent _N_
- White percentage.
- -bvalue _N_
- Black cutoff value.
- -wvalue _N_
- White cutoff value.
FAQ
What is the ppmnorm command used for?
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.
How do I run a basic ppmnorm example?
Run `ppmnorm [input.ppm] > [output.ppm]` in a terminal, then adjust file names, paths, flags, or remote targets for your system.
What does -bpercent _N_ do in ppmnorm?
Black percentage.