anwtfilterfloatlift9x7.java

jpeg2000算法实现

/*
 * CVS identifier:
 *
 * $Id: AnWTFilterFloatLift9x7.java,v 1.17 2000/12/12 16:41:36 grosbois Exp $
 *
 * Class:                   AnWTFilterFloatLift9x7
 *
 * Description:             An analyzing wavelet filter implementing the
 *                          lifting 9x7 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 9x7 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 AnWTFilterFloat
 * */
public class AnWTFilterFloatLift9x7 extends AnWTFilterFloat {

    /** The low-pass synthesis filter of the 9x7 wavelet transform */
    private final static float LPSynthesisFilter[] = 
    { -0.091272f, -0.057544f, 0.591272f, 1.115087f,
      0.591272f, -0.057544f, -0.091272f};

    /** The high-pass synthesis filter of the 9x7 wavelet transform */
    private final static float HPSynthesisFilter[] =
        { 0.026749f, 0.016864f, -0.078223f, -0.266864f,
          0.602949f, 
          -0.266864f, -0.078223f, 0.016864f, 0.026749f };
    
    /** The value of the first lifting step coefficient */
    public final static float ALPHA = -1.586134342f;

    /** The value of the second lifting step coefficient */
    public final static float BETA = -0.05298011854f;

    /** The value of the third lifting step coefficient */
    public final static float GAMMA = 0.8829110762f;

    /** The value of the fourth lifting step coefficient */
    public final static float DELTA = 0.443568522f;

    /** The value of the low-pass subband normalization factor */
    public final static float KL = 0.8128930655f;//1.149604398f;

    /** The value of the high-pass subband normalization factor */
    public final static float KH = 1.230174106f;//0.8698644523f;
    
    /**
     * An implementation of the analyze_lpf() method that works on int
     * data, for the forward 9x7 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 [ALPHA 1 ALPHA]. 
     *
     * <P>The coefficients of the second lifting step are [BETA 1 BETA].
     * 
     * <P>The coefficients of the third lifting step are [GAMMA 1 GAMMA]. 
     *
     * <P>The coefficients of the fourth lifting step are [DELTA 1 DELTA].
     *
     * <P>The low-pass and high-pass subbands are normalized by respectively
     * a factor of KL and a factor of KH   
     * 
     * @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(float inSig[], int inOff, int inLen, int inStep, 
                     float lowSig[], int lowOff, int lowStep,
                     float highSig[], int highOff, int highStep) {
        int i,maxi;
        int iStep = 2 * inStep; //Subsampling in inSig
        int ik;    //Indexing inSig
        int lk;    //Indexing lowSig
        int hk;    //Indexing highSig
        
        // Generate intermediate high frequency subband
        
        //Initialize counters
        ik = inOff + inStep;
        lk = lowOff;
        hk = highOff;
        
        //Apply first lifting step to each "inner" sample
        for( i = 1, maxi = inLen-1; i < maxi; i += 2 ) {           
            highSig[hk] = inSig[ik] + 
                ALPHA*(inSig[ik-inStep] + inSig[ik+inStep]);
            
            ik += iStep;   
            hk += highStep;
        }

        //Handle head boundary effect if input signal has even length
        if(inLen % 2 == 0) {
           highSig[hk] = inSig[ik] + 2*ALPHA*inSig[ik-inStep];
        }
        
        // Generate intermediate low frequency subband
        
        //Initialize counters
        ik = inOff;
        lk = lowOff;
        hk = highOff;
 
        if(inLen>1) {
            lowSig[lk] = inSig[ik] + 2*BETA*highSig[hk];
        }
        else {
            lowSig[lk] = inSig[ik];
        }
        
        ik += iStep;
        lk += lowStep;
        hk += highStep;
 
        //Apply lifting step to each "inner" sample
        for( i = 2, maxi = inLen-1; i < maxi; i += 2 ) {
            lowSig[lk] = inSig[ik] + 
                BETA*(highSig[hk-highStep] + highSig[hk]);
            
            ik += iStep;
            lk += lowStep;  
            hk += highStep;
        }
        
        //Handle head boundary effect if input signal has odd length
        if((inLen % 2 == 1)&&(inLen>2)) {
            lowSig[lk] =  inSig[ik] + 2*BETA*highSig[hk-highStep];
        }
        
        // Generate high frequency subband
         
        //Initialize counters
        lk = lowOff;
        hk = highOff;

        //Apply first lifting step to each "inner" sample
        for(i = 1, maxi = inLen-1; i < maxi; i += 2)  {           
            highSig[hk] += GAMMA*(lowSig[lk] + lowSig[lk+lowStep]);
            
            lk += lowStep;   
            hk += highStep;
        }

        //Handle head boundary effect if input signal has even length
        if(inLen % 2 == 0) {
            highSig[hk] += 2*GAMMA*lowSig[lk];
        }    

        // Generate low frequency subband
        
        //Initialize counters
        lk = lowOff;
        hk = highOff;
 
        //Handle tail boundary effect
        //If access the overlap then perform the lifting step
        if(inLen>1){
            lowSig[lk] += 2*DELTA*highSig[hk];
        }

        lk += lowStep;
        hk += highStep;
 
        //Apply lifting step to each "inner" sample
        for(i = 2, maxi = inLen-1; i < maxi; i += 2) {
            lowSig[lk] +=  
                DELTA*(highSig[hk - highStep] + highSig[hk]);
            
            lk += lowStep;  
            hk += highStep;
        }
        
        //Handle head boundary effect if input signal has odd length
        if((inLen % 2 == 1)&&(inLen>2)) {
            lowSig[lk] +=  2*DELTA*highSig[hk-highStep];
        }

        // Normalize low and high frequency subbands
         
        //Re-initialize counters
        lk = lowOff;
        hk = highOff;
         
        //Normalize each sample
        for( i=0 ; i<(inLen>>1); i++ ) {
            lowSig[lk] *= KL;
            highSig[hk] *= KH;
            lk += lowStep;  
            hk += highStep;
        }       
        //If the input signal has odd length then normalize the last low-pass
        //coefficient (if input signal is length one filter is identity)
        if( inLen%2==1 && inLen != 1) {
            lowSig[lk] *= KL;
        }
    }
    
    /**
     * An implementation of the analyze_hpf() method that works on int
     * data, for the forward 9x7 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 [ALPHA 1 ALPHA]. 
     *
     * <P>The coefficients of the second lifting step are [BETA 1 BETA].
     * 
     * <P>The coefficients of the third lifting step are [GAMMA 1 GAMMA]. 
     *
     * <P>The coefficients of the fourth lifting step are [DELTA 1 DELTA].
     *
     * <P>The low-pass and high-pass subbands are normalized by respectively
     * a factor of KL and a factor of KH   
     * 
     * @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(float inSig[], int inOff, int inLen, int inStep, 
                    float lowSig[], int lowOff, int lowStep,
                    float highSig[], int highOff, int highStep) {
                    
        int i,maxi;
        int iStep = 2 * inStep; //Subsampling in inSig
        int ik;    //Indexing inSig
        int lk;    //Indexing lowSig
        int hk;    //Indexing highSig
        
        // Generate intermediate high frequency subband
         
        //Initialize counters
        ik = inOff;
        lk = lowOff;
        hk = highOff;
        
        if ( inLen>1 ) {
            // apply symmetric extension.
            highSig[hk] = inSig[ik] + 2*ALPHA*inSig[ik+inStep];
        }
        else {
	    // Normalize for Nyquist gain