Package net.sourceforge.jiu.filters

Class ConvolutionKernelFilter

  • public class ConvolutionKernelFilter
extends ImageToImageOperation
    Applies a convolution kernel filter to an image.

    Supported image types

    Only image types that store intensity samples are supported. Right now, this only includes GrayIntegerImage and RGBIntegerImage.

    Usage example

    Standard approach (set up everything yourself): 
     ConvolutionKernelFilter filter = new ConvolutionKernelFilter();
 filter.setKernel(ConvolutionKernelFilter.TYPE_SHARPEN);
 filter.setInputImage(image);
 filter.process();
 PixelImage sharpenedImage = filter.getOutputImage();
    Use static convenience method on image img: 
     PixelImage filteredImage = ConvolutionKernelFilter.filter(img, ConvolutionKernelFilter.TYPE_BLUR);

    Credits

    The implementation of the filter was created by members of the Java newsgroup de.comp.lang.java and adapted to the JIU framework by Marco Schmidt. As it was done in a contest style where people improved other people's work, and even more people suggested ideas, tested results and discussed the contest it is (1) hard to tell who won the contest and (2) only fair to list all persons involved.

    The resulting implementation is significantly faster than the reference implementation. The contest was started by the posting [JPEC#3] Vorschläge to de.comp.lang.java by Marco Schmidt (2001-02-18) and was ended by the posting [JPEC#3] Ergebnisse (2001-03-07). A Usenet archive like Google Groups should be able to provide the postings.

    Author:
    Bernd Eckenfels, Carl Rosenberger, Dietmar Münzenberger, Karsten Schulz, Marco Kaiser, Marco Schmidt, Peter Luschny, Peter Schneider, Ramin Sadre, Roland Dieterich, Thilo Schwidurski

    • Field Detail

      • TYPE_PSYCHEDELIC_DISTILLATION

        public static final int TYPE_PSYCHEDELIC_DISTILLATION
        See Also:
        Constant Field Values

      • TYPE_HORIZONTAL_PREWITT

        public static final int TYPE_HORIZONTAL_PREWITT
        See Also:
        Constant Field Values

      • BLUR_DATA

        private static final int[] BLUR_DATA

      • SHARPEN_DATA

        private static final int[] SHARPEN_DATA

      • EDGE_DETECTION_DATA

        private static final int[] EDGE_DETECTION_DATA

      • EMBOSS_DATA

        private static final int[] EMBOSS_DATA

      • PSYCHEDELIC_DISTILLATION_DATA

        private static final int[] PSYCHEDELIC_DISTILLATION_DATA

      • LITHOGRAPH_DATA

        private static final int[] LITHOGRAPH_DATA

      • HORIZONTAL_SOBEL_DATA

        private static final int[] HORIZONTAL_SOBEL_DATA

      • VERTICAL_SOBEL_DATA

        private static final int[] VERTICAL_SOBEL_DATA

      • HORIZONTAL_PREWITT_DATA

        private static final int[] HORIZONTAL_PREWITT_DATA

      • VERTICAL_PREWITT_DATA

        private static final int[] VERTICAL_PREWITT_DATA

      • kernelBias

        private int kernelBias

      • kernelData

        private int[] kernelData

      • kernelDiv

        private int kernelDiv

      • kernelHeight

        private int kernelHeight

      • kernelWidth

        private int kernelWidth

    • Constructor Detail

      • ConvolutionKernelFilter

        public ConvolutionKernelFilter()

    • Method Detail

      • copyRow

        private void copyRow​(IntegerImage srcImage,
                     int srcChannelIndex,
                     int rowIndex,
                     int[] dest,
                     int destOffset,
                     int numBorderColumns)
        Copies row data from input image to buffer and replicates samples at the left and right border.

      • filter

        public static PixelImage filter​(PixelImage input,
                                int kernelType)
        Filters argument image with argument kernel type and returns output image. Static convenience method to do filtering with one line of code: 
        PixelImage blurredImage = ConvolutionKernelFilter.filter(in, ConvolutionKernelFilter.TYPE_BLUR);

      • process

        private void process​(int channelIndex,
                     IntegerImage in,
                     IntegerImage out)
        Applies the kernel to one of the channels of an image.
        Parameters:
        channelIndex - index of the channel to be filtered, must be from 0 to ByteChannelImage.getNumChannels() - 1

      • setKernel

        public void setKernel​(int[] data,
                      int width,
                      int height,
                      int div,
                      int bias)
        Sets properties of the kernel to be used in this operation.
        Parameters:
        data - the kernel coefficients; this one-dimensional array stores them in order top-to-bottom, left-to-right; the length of this array must be at least width times height
        width - the width of the kernel; must not be even
        height - the height of the kernel; must not be even
        div - the result is divided by this value after the addition of value (so this value must not be zero)
        bias - this value is added to the result before the division

      • setKernel

        public void setKernel​(ConvolutionKernelData ckd)
        Sets kernel data to be used for filtering.
        Parameters:
        ckd - all information necessary for filtering

      • setKernel

        public void setKernel​(int type)
        Sets one of the predefined kernel types to be used for filtering.
        Parameters:
        type - one of the TYPE_xyz constants of this class
        Throws:
        IllegalArgumentException - if the argument is not a valid TYPE_xyz constant