Applies a histogram equalization.
Applies a histogram equalization.
Namespace:
Aurigma.GraphicsMill.Transforms
Assembly:
Aurigma.GraphicsMill (in Aurigma.GraphicsMill.dll)
public sealed class HistogramEqualize : MaskTransform
Histogram equalization algorithm is used for automatically enhancing the image contrast. As usual it makes the image too posterized, that's why it is seldom used to with photos (you should use Contrast effect with Auto property set to true
). However it suits for scientific tasks (as a preparation before applying some specific algorithm like vectorization, recognition, etc).
The main idea of this algorithm is to build a look-up table (LUT) which makes the bitmap histogram equalized (all histogram entries are equal each other). Actually the histogram is never equalized absolutely, however this algorithm makes it as much as possible. After that this LUT is applied using LutTransform class.
This class enables you to use not only histogram of the source bitmap, but any other histogram too. In this case algorithm will build the LUT for this histogram, but apply this LUT on the source bitmap. To specify another histogram, use property Histogram. If you want to get a histogram from the bitmap automatically, set null
to this property.