corrade-vassal – Rev 1
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/*
* CVS identifier:
*
* $Id: AnWTFilterFloatLift9x7.java,v 1.18 2002/01/22 13:31:31 grosbois Exp $
*
* Class: AnWTFilterFloatLift9x7
*
* Description: An analyzing wavelet filter implementing the
* lifting 9x7 transform.
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix 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.
* */
using System;
using CSJ2K.j2k.wavelet;
using CSJ2K.j2k.image;
using CSJ2K.j2k;
using CSJ2K.j2k.codestream.writer;
namespace CSJ2K.j2k.wavelet.analysis
{
/// <summary> 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.
///
/// </summary>
/// <seealso cref="AnWTFilter">
/// </seealso>
/// <seealso cref="AnWTFilterFloat">
///
/// </seealso>
public class AnWTFilterFloatLift9x7:AnWTFilterFloat
{
/// <summary> Returns the negative support of the low-pass analysis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// </summary>
/// <returns> 2
///
/// </returns>
override public int AnLowNegSupport
{
get
{
return 4;
}
}
/// <summary> Returns the positive support of the low-pass analysis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// </summary>
/// <returns> The number of taps of the low-pass analysis filter in
/// the positive direction
///
/// </returns>
override public int AnLowPosSupport
{
get
{
return 4;
}
}
/// <summary> Returns the negative support of the high-pass analysis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// </summary>
/// <returns> The number of taps of the high-pass analysis filter in
/// the negative direction
///
/// </returns>
override public int AnHighNegSupport
{
get
{
return 3;
}
}
/// <summary> Returns the positive support of the high-pass analysis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// </summary>
/// <returns> The number of taps of the high-pass analysis filter in
/// the positive direction
///
/// </returns>
override public int AnHighPosSupport
{
get
{
return 3;
}
}
/// <summary> Returns the negative support of the low-pass synthesis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// <P>A MORE PRECISE DEFINITION IS NEEDED
///
/// </summary>
/// <returns> The number of taps of the low-pass synthesis filter in
/// the negative direction
///
/// </returns>
override public int SynLowNegSupport
{
get
{
return 3;
}
}
/// <summary> Returns the positive support of the low-pass synthesis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// <P>A MORE PRECISE DEFINITION IS NEEDED
///
/// </summary>
/// <returns> The number of taps of the low-pass synthesis filter in
/// the positive direction
///
/// </returns>
override public int SynLowPosSupport
{
get
{
return 3;
}
}
/// <summary> Returns the negative support of the high-pass synthesis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// <P>A MORE PRECISE DEFINITION IS NEEDED
///
/// </summary>
/// <returns> The number of taps of the high-pass synthesis filter in
/// the negative direction
///
/// </returns>
override public int SynHighNegSupport
{
get
{
return 4;
}
}
/// <summary> Returns the positive support of the high-pass synthesis
/// filter. That is the number of taps of the filter in the
/// negative direction.
///
/// <P>A MORE PRECISE DEFINITION IS NEEDED
///
/// </summary>
/// <returns> The number of taps of the high-pass synthesis filter in
/// the positive direction
///
/// </returns>
override public int SynHighPosSupport
{
get
{
return 4;
}
}
/// <summary> Returns the implementation type of this filter, as defined in
/// this class, such as WT_FILTER_INT_LIFT, WT_FILTER_FLOAT_LIFT,
/// WT_FILTER_FLOAT_CONVOL.
///
/// </summary>
/// <returns> WT_FILTER_INT_LIFT.
///
/// </returns>
override public int ImplType
{
get
{
return CSJ2K.j2k.wavelet.WaveletFilter_Fields.WT_FILTER_FLOAT_LIFT;
}
}
/// <summary> Returns the reversibility of the filter. A filter is considered
/// reversible if it is suitable for lossless coding.
///
/// </summary>
/// <returns> true since the 9x7 is reversible, provided the appropriate
/// rounding is performed.
///
/// </returns>
override public bool Reversible
{
get
{
return false;
}
}
/// <summary> Returns the type of filter used according to the FilterTypes
/// interface(W9x7).
///
/// </summary>
/// <seealso cref="FilterTypes">
///
/// </seealso>
/// <returns> The filter type.
///
/// </returns>
override public int FilterType
{
get
{
return CSJ2K.j2k.wavelet.FilterTypes_Fields.W9X7;
}
}
/// <summary>The low-pass synthesis filter of the 9x7 wavelet transform </summary>
//UPGRADE_NOTE: Final was removed from the declaration of 'LPSynthesisFilter'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
private static readonly float[] LPSynthesisFilter = new float[]{- 0.091272f, - 0.057544f, 0.591272f, 1.115087f, 0.591272f, - 0.057544f, - 0.091272f};
/// <summary>The high-pass synthesis filter of the 9x7 wavelet transform </summary>
//UPGRADE_NOTE: Final was removed from the declaration of 'HPSynthesisFilter'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
private static readonly float[] HPSynthesisFilter = new float[]{0.026749f, 0.016864f, - 0.078223f, - 0.266864f, 0.602949f, - 0.266864f, - 0.078223f, 0.016864f, 0.026749f};
/// <summary>The value of the first lifting step coefficient </summary>
public const float ALPHA = - 1.586134342f;
/// <summary>The value of the second lifting step coefficient </summary>
public const float BETA = - 0.05298011854f;
/// <summary>The value of the third lifting step coefficient </summary>
public const float GAMMA = 0.8829110762f;
/// <summary>The value of the fourth lifting step coefficient </summary>
public const float DELTA = 0.4435068522f;
/// <summary>The value of the low-pass subband normalization factor </summary>
public const float KL = 0.8128930655f;
/// <summary>The value of the high-pass subband normalization factor </summary>
public const float KH = 1.230174106f;
/// <summary> 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
///
/// </summary>
/// <param name="inSig">This is the array that contains the input
/// signal.
///
/// </param>
/// <param name="inOff">This is the index in inSig of the first sample to
/// filter.
///
/// </param>
/// <param name="inLen">This is the number of samples in the input signal
/// to filter.
///
/// </param>
/// <param name="inStep">This is the step, or interleave factor, of the
/// input signal samples in the inSig array.
///
/// </param>
/// <param name="lowSig">This is the array where the low-pass output
/// signal is placed.
///
/// </param>
/// <param name="lowOff">This is the index in lowSig of the element where
/// to put the first low-pass output sample.
///
/// </param>
/// <param name="lowStep">This is the step, or interleave factor, of the
/// low-pass output samples in the lowSig array.
///
/// </param>
/// <param name="highSig">This is the array where the high-pass output
/// signal is placed.
///
/// </param>
/// <param name="highOff">This is the index in highSig of the element where
/// to put the first high-pass output sample.
///
/// </param>
/// <param name="highStep">This is the step, or interleave factor, of the
/// high-pass output samples in the highSig array.
///
/// </param>
public override 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;
}
}
/// <summary> 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
///
/// </summary>
/// <param name="inSig">This is the array that contains the input
/// signal.
///
/// </param>
/// <param name="inOff">This is the index in inSig of the first sample to
/// filter.
///
/// </param>
/// <param name="inLen">This is the number of samples in the input signal
/// to filter.
///
/// </param>
/// <param name="inStep">This is the step, or interleave factor, of the
/// input signal samples in the inSig array.
///
/// </param>
/// <param name="lowSig">This is the array where the low-pass output
/// signal is placed.
///
/// </param>
/// <param name="lowOff">This is the index in lowSig of the element where
/// to put the first low-pass output sample.
///
/// </param>
/// <param name="lowStep">This is the step, or interleave factor, of the
/// low-pass output samples in the lowSig array.
///
/// </param>
/// <param name="highSig">This is the array where the high-pass output
/// signal is placed.
///
/// </param>
/// <param name="highOff">This is the index in highSig of the element where
/// to put the first high-pass output sample.
///
/// </param>
/// <param name="highStep">This is the step, or interleave factor, of the
/// high-pass output samples in the highSig array.
///
/// </param>
/// <seealso cref="AnWTFilter.analyze_hpf">
///
/// </seealso>
public override 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 removed
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
highSig[hk] = inSig[ik] * 2;
}
ik += iStep;
hk += highStep;
//Apply first lifting step to each "inner" sample
for (i = 2; i < inLen - 1; i += 2)
{
highSig[hk] = inSig[ik] + ALPHA * (inSig[ik - inStep] + inSig[ik + inStep]);
ik += iStep;
hk += highStep;
}
//If input signal has odd length then we perform the lifting step
// i.e. apply a symmetric extension.
if ((inLen % 2 == 1) && (inLen > 1))
{
highSig[hk] = inSig[ik] + 2 * ALPHA * inSig[ik - inStep];
}
// Generate intermediate low frequency subband
//Initialize counters
//ik = inOff + inStep;
ik = inOff + inStep;
lk = lowOff;
hk = highOff;
//Apply lifting step to each "inner" sample
// we are at the component boundary
for (i = 1; i < inLen - 1; i += 2)
{
lowSig[lk] = inSig[ik] + BETA * (highSig[hk] + highSig[hk + highStep]);
ik += iStep;
lk += lowStep;
hk += highStep;
}
if (inLen > 1 && inLen % 2 == 0)
{
// symetric extension
lowSig[lk] = inSig[ik] + 2 * BETA * highSig[hk];
}
// Generate high frequency subband
//Initialize counters
lk = lowOff;
hk = highOff;
if (inLen > 1)
{
// symmetric extension.
highSig[hk] += GAMMA * 2 * lowSig[lk];
}
//lk += lowStep;
hk += highStep;
//Apply first lifting step to each "inner" sample
for (i = 2; i < inLen - 1; i += 2)
{
highSig[hk] += GAMMA * (lowSig[lk] + lowSig[lk + lowStep]);
lk += lowStep;
hk += highStep;
}
//Handle head boundary effect
if (inLen > 1 && inLen % 2 == 1)
{
// symmetric extension.
highSig[hk] += GAMMA * 2 * lowSig[lk];
}
// Generate low frequency subband
//Initialize counters
lk = lowOff;
hk = highOff;
// we are at the component boundary
for (i = 1; i < inLen - 1; i += 2)
{
lowSig[lk] += DELTA * (highSig[hk] + highSig[hk + highStep]);
lk += lowStep;
hk += highStep;
}
if (inLen > 1 && inLen % 2 == 0)
{
lowSig[lk] += DELTA * 2 * highSig[hk];
}
// 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 high-pass
//coefficient (if input signal is length one filter is identity)
if (inLen % 2 == 1 && inLen != 1)
{
highSig[hk] *= KH;
}
}
/// <summary> Returns the time-reversed low-pass synthesis waveform of the
/// filter, which is the low-pass filter. This is the time-reversed
/// impulse response of the low-pass synthesis filter. It is used
/// to calculate the L2-norm of the synthesis basis functions for a
/// particular subband (also called energy weight).
///
/// <P>The returned array may not be modified (i.e. a reference to
/// the internal array may be returned by the implementation of
/// this method).
///
/// </summary>
/// <returns> The time-reversed low-pass synthesis waveform of the
/// filter.
///
/// </returns>
public override float[] getLPSynthesisFilter()
{
return LPSynthesisFilter;
}
/// <summary> Returns the time-reversed high-pass synthesis waveform of the
/// filter, which is the high-pass filter. This is the
/// time-reversed impulse response of the high-pass synthesis
/// filter. It is used to calculate the L2-norm of the synthesis
/// basis functions for a particular subband (also called energy
/// weight).
///
/// <P>The returned array may not be modified (i.e. a reference to
/// the internal array may be returned by the implementation of
/// this method).
///
/// </summary>
/// <returns> The time-reversed high-pass synthesis waveform of the
/// filter.
///
/// </returns>
public override float[] getHPSynthesisFilter()
{
return HPSynthesisFilter;
}
/// <summary> Returns true if the wavelet filter computes or uses the
/// same "inner" subband coefficient as the full frame wavelet transform,
/// and false otherwise. In particular, for block based transforms with
/// reduced overlap, this method should return false. The term "inner"
/// indicates that this applies only with respect to the coefficient that
/// are not affected by image boundaries processings such as symmetric
/// extension, since there is not reference method for this.
///
/// <P>The result depends on the length of the allowed overlap when
/// compared to the overlap required by the wavelet filter. It also
/// depends on how overlap processing is implemented in the wavelet
/// filter.
///
/// </summary>
/// <param name="tailOvrlp">This is the number of samples in the input
/// signal before the first sample to filter that can be used for
/// overlap.
///
/// </param>
/// <param name="headOvrlp">This is the number of samples in the input
/// signal after the last sample to filter that can be used for
/// overlap.
///
/// </param>
/// <param name="inLen">This is the lenght of the input signal to filter.The
/// required number of samples in the input signal after the last sample
/// depends on the length of the input signal.
///
/// </param>
/// <returns> true if both overlaps are greater than 2, and correct
/// processing is applied in the analyze() method.
///
/// </returns>
public override bool isSameAsFullWT(int tailOvrlp, int headOvrlp, int inLen)
{
//If the input signal has even length.
if (inLen % 2 == 0)
{
if (tailOvrlp >= 4 && headOvrlp >= 3)
return true;
else
return false;
}
//Else if the input signal has odd length.
else
{
if (tailOvrlp >= 4 && headOvrlp >= 4)
return true;
else
return false;
}
}
/// <summary> Tests if the 'obj' object is the same filter as this one. Two filters
/// are the same if the same filter code should be output for both filters
/// by the encodeFilterCode() method.
///
/// <P>Currently the implementation of this method only tests if 'obj' is
/// also of the class AnWTFilterFloatLift9x7
///
/// </summary>
/// <param name="The">object against which to test inequality.
///
/// </param>
public override bool Equals(System.Object obj)
{
// To spped up test, first test for reference equality
return obj == this || obj is AnWTFilterFloatLift9x7;
}
/// <summary>Debugging method </summary>
public override System.String ToString()
{
return "w9x7";
}
//UPGRADE_NOTE: The following method implementation was automatically added to preserve functionality. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1306'"
public override int GetHashCode()
{
return base.GetHashCode();
}
}
}
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