Examples of ucar.jpeg.jj2000.j2k.quantization.quantizer.Quantizer

Package ucar.jpeg.jj2000.j2k.quantization.quantizer

Examples of ucar.jpeg.jj2000.j2k.quantization.quantizer.Quantizer

ucar.jpeg.jj2000.j2k.image.DataBlkInt
This abstract class provides the general interface for quantizers. The input of a quantizer is the output of a wavelet transform. The output of the quantizer is the set of quantized wavelet coefficients represented in sign-magnitude notation (see below).
This class provides default implementation for most of the methods (wherever it makes sense), under the assumption that the image, component dimensions, and the tiles, are not modifed by the quantizer. If it is not the case for a particular implementation, then the methods should be overriden.

Sign magnitude representation is used (instead of two's complement) for the output data. The most significant bit is used for the sign (0 if positive, 1 if negative). Then the magnitude of the quantized coefficient is stored in the next M most significat bits. The rest of the bits (least significant bits) can contain a fractional value of the quantized coefficient. This fractional value is not to be coded by the entropy coder. However, it can be used to compute rate-distortion measures with greater precision.

The value of M is determined for each subband as the sum of the number of guard bits G and the nominal range of quantized wavelet coefficients in the corresponding subband (Rq), minus 1:

M = G + Rq -1

The value of G should be the same for all subbands. The value of Rq depends on the quantization step size, the nominal range of the component before the wavelet transform and the analysis gain of the subband (see Subband).

The blocks of data that are requested should not cross subband boundaries.

NOTE: At the moment only quantizers that implement the 'CBlkQuantDataSrcEnc' interface are supported.
@see Subband


        // Creates ForwardWT (forward wavelet transform)
        ForwardWT dwt = ForwardWT.createInstance(converter, j2kwparam);


        // Creates Quantizer
        Quantizer quant = Quantizer.createInstance(dwt,j2kwparam);


        // Creates ROIScaler
        ROIScaler rois = ROIScaler.createInstance(quant, j2kwparam);


        // Creates EntropyCoder

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    int E = drs.getBinaryScaleFactor();
    //System.out.println( "DS E=" + E );
    float EE = (float) java.lang.Math.pow((double) 2.0, (double) E);
    //System.out.println( "DS EE=" + EE );


    Grib2JpegDecoder g2j = null;
    int numberPoints = 0;
    try {
      if (nb != 0) {  // there's data to decode
        String[] argv = new String[4];
        argv[0] = "-rate";
        argv[1] = Integer.toString(nb);
        argv[2] = "-verbose";
        argv[3] = "off";
        //argv[ 4 ] = "-debug" ;
        //argv[ 2 ] = "-nocolorspace" ;
        //argv[ 3 ] = "-Rno_roi" ;
        //argv[ 4 ] = "-cdstr_info" ;
        //argv[ 5 ] = "-verbose" ;
        g2j = new Grib2JpegDecoder(argv);
        // how jpeg2000.jar use to decode, used raf
        //g2j.decode(raf, length - 5);
        // jpeg-1.0.jar added method to have the data read first
        byte[] buf = new byte[ length - 5 ];
        raf.read( buf );
        g2j.decode( buf );
      }
      numberPoints = gds.getGdsVars().getNumberPoints();
      //System.out.println( "DS GDS NumberPoints=" +  gds.getNumberPoints() );
      data = new float[numberPoints];
      boolean[] bitmap = bms.getBitmap();

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        float [][] out = new float [3][];
        float [][] in  = new float [3][];


        for (i=0;i<3;++i) {
            in[i]  = inblk [i] .getDataFloat();
            outblk[i] = new DataBlkFloat ();
            copyGeometry (outblk[i],inblk[i]);
            outblk[i].offset = inblk[i].offset;
            out[i] = new float [length];
            outblk[i].setData (out[i]); }

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        int [][] out = new int [3][];
        int [][] in  = new int [3][];


        for (i=0;i<3;++i) {
            in[i]  = inblk [i] .getDataInt();
            outblk[i] = new DataBlkInt ();
            copyGeometry (outblk[i],inblk[i]);
            outblk[i].offset = inblk[i].offset;
            out[i] = new int [length];
            outblk[i].setData (out[i]); }

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