anwtfilterintlift5x3.java

java 实现的小波压缩库代码,内部包含了分析器

/*
 * CVS identifier:
 *
 * $Id: AnWTFilterIntLift5x3.java,v 1.14 2000/12/12 16:45:17 grosbois Exp $
 *
 * Class:                   AnWTFilterIntLift5x3
 *
 * Description:             An analyzing wavelet filter implementing the
 *                          lifting 5x3 transform.
 *
 *
 *
 * COPYRIGHT:
 * 
 * This software module was originally developed by Rapha雔 Grosbois and
 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
 * Askel鰂 (Ericsson Radio Systems AB); and Bertrand Berthelot, David
 * Bouchard, F閘ix Henry, Gerard Mozelle and Patrice Onno (Canon Research
 * Centre France S.A) in the course of development of the JPEG2000
 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
 * software module is an implementation of a part of the JPEG 2000
 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
 * Partners) agree not to assert against ISO/IEC and users of the JPEG
 * 2000 Standard (Users) any of their rights under the copyright, not
 * including other intellectual property rights, for this software module
 * with respect to the usage by ISO/IEC and Users of this software module
 * or modifications thereof for use in hardware or software products
 * claiming conformance to the JPEG 2000 Standard. Those intending to use
 * this software module in hardware or software products are advised that
 * their use may infringe existing patents. The original developers of
 * this software module, JJ2000 Partners and ISO/IEC assume no liability
 * for use of this software module or modifications thereof. No license
 * or right to this software module is granted for non JPEG 2000 Standard
 * conforming products. JJ2000 Partners have full right to use this
 * software module for his/her own purpose, assign or donate this
 * software module to any third party and to inhibit third parties from
 * using this software module for non JPEG 2000 Standard conforming
 * products. This copyright notice must be included in all copies or
 * derivative works of this software module.
 * 
 * Copyright (c) 1999/2000 JJ2000 Partners.
 *  */
package jj2000.j2k.wavelet.analysis;

import jj2000.j2k.wavelet.*;
import jj2000.j2k.image.*;
import jj2000.j2k.*;
import jj2000.j2k.codestream.writer.*;

/**
 * This class inherits from the analysis wavelet filter definition for int
 * data. It implements the forward wavelet transform specifically for the 5x3
 * filter. The implementation is based on the lifting scheme.
 *
 * <P>See the AnWTFilter class for details such as normalization, how to split
 * odd-length signals, etc. In particular, this method assumes that the
 * low-pass coefficient is computed first.
 *
 * @see AnWTFilter
 * @see AnWTFilterInt
 * */
public class AnWTFilterIntLift5x3 extends AnWTFilterInt {

    /** The low-pass synthesis filter of the 5x3 wavelet transform */
    private final static float LPSynthesisFilter[] = 
    { 0.5f, 1f, 0.5f };

    /** The high-pass synthesis filter of the 5x3 wavelet transform */
    private final static float HPSynthesisFilter[] =
    { -0.125f, -0.25f, 0.75f, -0.25f, -0.125f };
    
    /**
     * An implementation of the analyze_lpf() method that works on int data,
     * for the forward 5x3 wavelet transform using the lifting scheme. See the
     * general description of the analyze_lpf() method in the AnWTFilter class
     * for more details.
     *
     * <P>The coefficients of the first lifting step are [-1/2 1 -1/2]. 
     *
     * <P>The coefficients of the second lifting step are [1/4 1 1/4].
     * 
     * @param inSig This is the array that contains the input
     * signal.
     *
     * @param inOff This is the index in inSig of the first sample to
     * filter.
     *
     * @param inLen This is the number of samples in the input signal
     * to filter.
     *
     * @param inStep This is the step, or interleave factor, of the
     * input signal samples in the inSig array.
     *
     * @param lowSig This is the array where the low-pass output
     * signal is placed.
     *
     * @param lowOff This is the index in lowSig of the element where
     * to put the first low-pass output sample.
     *
     * @param lowStep This is the step, or interleave factor, of the
     * low-pass output samples in the lowSig array.
     *
     * @param highSig This is the array where the high-pass output
     * signal is placed.
     *
     * @param highOff This is the index in highSig of the element where
     * to put the first high-pass output sample.
     *
     * @param highStep This is the step, or interleave factor, of the
     * high-pass output samples in the highSig array.
     * */
    public 
        void analyze_lpf(int inSig[], int inOff, int inLen, int inStep, 
                     int lowSig[], int lowOff, int lowStep,
                     int highSig[], int highOff, int highStep) {
        int i;
        int iStep = 2 * inStep; //Subsampling in inSig
        int ik; //Indexing inSig
        int lk; //Indexing lowSig
        int hk; //Indexing highSig
        
        /*
         *Generate high frequency subband
         */
        
        //Initialize counters
        ik = inOff + inStep;
        hk = highOff;
        
        //Apply first lifting step to each "inner" sample.
        for(i = 1; i < inLen-1; i += 2) {           
            highSig[hk] = inSig[ik] - 
                ((inSig[ik-inStep] + inSig[ik+inStep])>>1);
            
            ik += iStep;   
            hk += highStep;
        }

        //Handle head boundary effect if input signal has even length.
        if( inLen % 2 == 0 ) {
            highSig[hk] = inSig[ik] - ((2*inSig[ik-inStep])>>1);
        }    
        
        /*
         *Generate low frequency subband
         */
        
        //Initialize counters
        ik = inOff;
        lk = lowOff;
        hk = highOff;
        
        if(inLen>1) {
            lowSig[lk] = inSig[ik] + ((highSig[hk] + 1)>>1);
        }
        else {
            lowSig[lk] = inSig[ik];
        }
        
        ik += iStep;
        lk += lowStep;  
        hk += highStep;
 
        //Apply lifting step to each "inner" sample.
        for(i = 2; i < inLen-1; i += 2) {
            lowSig[lk] = inSig[ik] + 
                ((highSig[hk-highStep] + highSig[hk] + 2)>> 2);
            
            ik += iStep;
            lk += lowStep;  
            hk += highStep;
        }
        
        //Handle head boundary effect if input signal has odd length.
        if(inLen % 2 == 1) {
            if(inLen>2) {
                lowSig[lk] = inSig[ik] + ((2*highSig[hk-highStep]+2)>>2);
            }
        }    
    }
    
    /**
     * An implementation of the analyze_hpf() method that works on int data,
     * for the forward 5x3 wavelet transform using the lifting scheme. See the
     * general description of the analyze_hpf() method in the AnWTFilter class
     * for more details.
     *
     * <P>The coefficients of the first lifting step are [-1/2 1 -1/2]. 
     *
     * <P>The coefficients of the second lifting step are [1/4 1 1/4].
     * 
     * @param inSig This is the array that contains the input
     * signal.
     *
     * @param inOff This is the index in inSig of the first sample to
     * filter.
     *
     * @param inLen This is the number of samples in the input signal
     * to filter.
     *
     * @param inStep This is the step, or interleave factor, of the
     * input signal samples in the inSig array.
     *
     * @param lowSig This is the array where the low-pass output
     * signal is placed.
     *
     * @param lowOff This is the index in lowSig of the element where
     * to put the first low-pass output sample.
     *
     * @param lowStep This is the step, or interleave factor, of the
     * low-pass output samples in the lowSig array.
     *
     * @param highSig This is the array where the high-pass output
     * signal is placed.
     *
     * @param highOff This is the index in highSig of the element where
     * to put the first high-pass output sample.
     *
     * @param highStep This is the step, or interleave factor, of the
     * high-pass output samples in the highSig array.
     *
     * @see AnWTFilter#analyze_hpf
     * */
    public 
        void analyze_hpf(int inSig[], int inOff, int inLen, int inStep, 
                     int lowSig[], int lowOff, int lowStep,
                     int highSig[], int highOff, int highStep) {
        int i;
        int iStep = 2 * inStep; //Subsampling in inSig
        int ik; //Indexing inSig
        int lk; //Indexing lowSig
        int hk; //Indexing highSig
        
        /*
         *Generate high frequency subband
         */
        
        //Initialize counters
        ik = inOff;
        hk = highOff;
      
        if ( inLen>1 ) {
            // apply a symmetric extension.
            highSig[hk] = inSig[ik] - inSig[ik+inStep];
        }
        else {
	    // Normalize for Nyquist gain
            highSig[hk] = inSig[ik]<<1;
        }
        
        ik += iStep;   
        hk += highStep;
        
        //Apply first lifting step to each "inner" sample.
        if ( inLen>3 ) {
            for(i = 2; i < inLen-1; i += 2) {      
                highSig[hk] = inSig[ik] - 
                    ((inSig[ik-inStep] + inSig[ik+inStep])>>1);
                ik += iStep;