Class GammaCorrection


  • public class GammaCorrection
    extends LookupTableOperation
    Corrects the gamma of an image. Works with GrayIntegerImage, RGBIntegerImage and Paletted8Image. Only the palette is manipulated for paletted images.

    Changes intensity values by applying the formula f(x) = MAX * (x / MAX)(1 / gamma) to each x from [0 ; MAX] to them. The MAX value is the maximum value allowed for an intensity value of the corresponding channel. It is determined by calling IntegerImage.getMaxSample(int) on the input image. The gamma parameter must be given to a GammaCorrection operation before the call to process(net.sourceforge.jiu.data.Paletted8Image, net.sourceforge.jiu.data.Paletted8Image) is made. The valid interval for gamma is (0.0 ; MAX_GAMMA] (so 0.0 is not a valid value). Gamma values smaller than 1 will make the image darker, values larger than 1 will make it brighter.

    Usage example

     GammaCorrection gamma = new GammaCorrection();
     gamma.setInputImage(image);
     gamma.setGamma(2.2);
     gamma.process();
     PixelImage correctedImage = gamma.getOutputImage();
     
    Author:
    Marco Schmidt
    • Field Detail

      • MAX_GAMMA

        public static final double MAX_GAMMA
        The maximum allowed value for gamma.
        See Also:
        Constant Field Values
      • gamma

        private double gamma
    • Constructor Detail

      • GammaCorrection

        public GammaCorrection()
    • Method Detail

      • createLookupTable

        private final int[] createLookupTable​(int numSamples)
        Creates a lookup table that holds all new values for samples 0 to numSamples - 1.
      • getGamma

        public double getGamma()
        Returns the gamma value to be used for this operation.
        Returns:
        gamma value between 0 (not included) and MAX_GAMMA
      • setGamma

        public void setGamma​(double newGamma)
        Sets a new gamma value to be used in this operation.
        Parameters:
        newGamma - the new gamma value must be > 0.0 and <= MAX_GAMMA
        Throws:
        IllegalArgumentException - if the argument is not in the described interval