HOWTO: Compare similar images to determine higher contrast

The concept of contrast of a particular image can have multiple meanings, but they usually revolve around the ability to distinguish objects in the image. However, if you have 2 similar images, like the same object photographed by 2 devices from the same angle, you can get a measure of which one has the "higher" contrast value.

In general, a higher contrast image will have a greater spread of the histogram curve, since this will mean the contents of the image have more differences in their intensities, which leads to greater ability to distinguish objects.
You can use StatisticsInformationCommand Class to get the properties of the histogram of the image and detect which one has higher contrast based on which image has a higher standard deviation.
For an example, see the following code which was tested using v18 of LEADTOOLS .NET classes (but other versions should work too):
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RasterImage img1 = codecs.Load(fileName1);
StatisticsInformationCommand cmd1 = new StatisticsInformationCommand(RasterColorChannel.Master, 0, 255);
RasterImage img2 = codecs.Load(fileName2);
StatisticsInformationCommand cmd2 = new StatisticsInformationCommand(RasterColorChannel.Master, 0, 255);
cmd1.Run(img1);
cmd2.Run(img2);
if (cmd1.StandardDeviation > cmd2.StandardDeviation)
{
   MessageBox.Show(fileName1 + " likely has higher contrast");
}
else if (cmd1.StandardDeviation < cmd2.StandardDeviation)
   MessageBox.Show(fileName2 + " likely has higher contrast");
else
   MessageBox.Show("Standard deviation is equal");
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