= Histogram Operations = {{{ #!html
Example of a histogram match using USGS DOQs. The image on the left is a composite of 4 different DOQs. Each DOQ has a different radiometry. The image on the right is the output from a histogram match.
}}} OSSIM provides histogram-based color enhancement options to change the output of your data based on a histogram file. Histogram operations include: * '''Auto''' Automatically adjust the histogram based on the min and max histogram values. * '''Match''' Automatically adjust the histogram to match another image. * '''Linear''' Linear contrast stretch using a standard deviation from the mean (e.g. 1, 2, or 3) or a user defined min/max value. [[BR]] Note that histogram operation operations require an input image and a corresponding histogram file ("*.his"). The histogram file can be generated using [wiki:create_histo ossim-create-histo] or [wiki:img2rr ossim-img2rr]. === Related Applications === * [wiki:orthoigen ossim-orthoigen] * [wiki:img2rr ossim-img2rr] === Related Links === * [http://download.osgeo.org/ossim/tutorials/pdfs/Histogram.pdf]