This method uses gamma correction to adjust the YCrCb values of a raster image.

[Visual Basic]
Public Function YCCGamma(yb As Double, cr As Double, cb As Double) As Boolean
[C#]
public bool YCCGamma(double yb, double cr, double cb);

Parameters

yb
     The gamma factor for the Y plane

cr
     The gamma factor for the Cr plane

cb
     The gamma factor for the Cb plane

Return Value

Returns True if successful. Returns False if unsuccessful.

Explanation

The YCCGamma method uses gamma correction to adjust the YCrCb values and overall brightness of a raster image. The formula used to calculate the output is given below:

Where x is the input YCrCb value, y is the output YCrCb value and bright is the gamma factor for the Y, Cr and Cb planes. (The Yb, Cr, and Cb parameters respectively).

When the Yb, Cr, and Cb parameters all equal 0, the input RGB values and output YCrCb values are equal meaning there is no change in the image. As the Yb, Cr, and Cb parameters increase in a positive direction, the output YCrCb values become lower than the input YCrCb values. As the Yb, Cr, and Cb parameters increase in a negative direction, the output YCrCb values become higher than the input YCrCb values. Please refer to the diagram below which shows the change in YCrCb values for a gamma factor of 1 and also for a gamma factor of -1.

To execute the YCCGamma method, set the image handle of the image in the SourceImage property. The YCCGamma method supports 1, 4, 8, 16, 24, and 32 bit images.

  1. To use a mask image, set the SelectMode property to EffectMask. Set the mask image handle in the SourceMask property
  2. To process the total image, set the SelectMode property to EffectAll
  3. To process the polygonal area on the image, set the SelectMode property to EffectPolygon. Select the polygon by setting the appropriate coordinate values for the points of the polygon in the Point property
  4. To process an elliptical area on the image, set the SelectMode property to EffectEllipse. Select the ellipse by setting the appropriate values for the bounding rectangle in the Rect property

When the SelectMode property is set to EffectPolygon or EffectEllipse, the appropriate values must be set in the Inside property. When a 1, 4, or 8 bit image is processed, the total image will be processed regardless of the value set in the SelectMode property.

If successful the resulting raster image data is set in the DestinationImage property.

See Also

Effect Class | Effect Members

The ImageKit.NET3 is created by Newtone Corporation