001/*
002 * $RCSfile: StdDequantizerParams.java,v $
003 * $Revision: 1.1 $
004 * $Date: 2005/02/11 05:02:19 $
005 * $State: Exp $
006 *
007 * Class:                   StdDequantizerParams
008 *
009 * Description:             Parameters for the scalar deadzone dequantizers
010 *
011 *
012 *
013 * COPYRIGHT:
014 *
015 * This software module was originally developed by Raphaël Grosbois and
016 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
017 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
018 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
019 * Centre France S.A) in the course of development of the JPEG2000
020 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
021 * software module is an implementation of a part of the JPEG 2000
022 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
023 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
024 * Partners) agree not to assert against ISO/IEC and users of the JPEG
025 * 2000 Standard (Users) any of their rights under the copyright, not
026 * including other intellectual property rights, for this software module
027 * with respect to the usage by ISO/IEC and Users of this software module
028 * or modifications thereof for use in hardware or software products
029 * claiming conformance to the JPEG 2000 Standard. Those intending to use
030 * this software module in hardware or software products are advised that
031 * their use may infringe existing patents. The original developers of
032 * this software module, JJ2000 Partners and ISO/IEC assume no liability
033 * for use of this software module or modifications thereof. No license
034 * or right to this software module is granted for non JPEG 2000 Standard
035 * conforming products. JJ2000 Partners have full right to use this
036 * software module for his/her own purpose, assign or donate this
037 * software module to any third party and to inhibit third parties from
038 * using this software module for non JPEG 2000 Standard conforming
039 * products. This copyright notice must be included in all copies or
040 * derivative works of this software module.
041 *
042 * Copyright (c) 1999/2000 JJ2000 Partners.
043 */
044package jj2000.j2k.quantization.dequantizer;
045
046import jj2000.j2k.io.*;
047import jj2000.j2k.wavelet.*;
048import jj2000.j2k.quantization.*;
049import jj2000.j2k.entropy.decoder.*;
050import jj2000.j2k.image.*;
051import jj2000.j2k.util.*;
052import jj2000.j2k.codestream.*;
053import jj2000.j2k.codestream.reader.*;
054
055import java.io.*;
056
057/**
058 * This class holds the parameters for the scalar deadzone dequantizer
059 * (StdDequantizer class) for the current tile. Its constructor decodes the
060 * parameters from the main header and tile headers.
061 *
062 * @see StdDequantizer
063 * */
064public class StdDequantizerParams extends DequantizerParams {
065
066    /**
067     * The quantization step "exponent" value, for each resolution level and
068     * subband, as it appears in the codestream. The first index is the
069     * resolution level, and the second the subband index (within the
070     * resolution level), as specified in the Subband class. When in derived
071     * quantization mode only the first resolution level (level 0) appears.
072     *
073     * <P>For non-reversible systems this value corresponds to ceil(log2(D')),
074     * where D' is the quantization step size normalized to data of a dynamic
075     * range of 1. The true quantization step size is (2^R)*D', where R is
076     * ceil(log2(dr)), where 'dr' is the dynamic range of the subband samples,
077     * in the corresponding subband.
078     *
079     * <P>For reversible systems the exponent value in 'exp' is used to
080     * determine the number of magnitude bits in the quantized
081     * coefficients. It is, in fact, the dynamic range of the subband data.
082     *
083     * <P>In general the index of the first subband in a resolution level is
084     * not 0. The exponents appear, within each resolution level, at their
085     * subband index, and not in the subband order starting from 0. For
086     * instance, resolution level 3, the first subband has the index 16, then
087     * the exponent of the subband is exp[3][16], not exp[3][0].
088     *
089     * @see Subband
090     * */
091    public int exp[][];
092
093    /**
094     * The quantization step for non-reversible systems, normalized to a
095     * dynamic range of 1, for each resolution level and subband, as derived
096     * from the exponent-mantissa representation in the codestream. The first
097     * index is the resolution level, and the second the subband index (within
098     * the resolution level), as specified in the Subband class. When in
099     * derived quantization mode only the first resolution level (level 0)
100     * appears.
101     *
102     * <P>The true step size D is obtained as follows: D=(2^R)*D', where
103     * 'R=ceil(log2(dr))' and 'dr' is the dynamic range of the subband
104     * samples, in the corresponding subband.
105     *
106     * <P>This value is 'null' for reversible systems (i.e. there is no true
107     * quantization, 'D' is always 1).
108     *
109     * <P>In general the index of the first subband in a resolution level is
110     * not 0. The steps appear, within each resolution level, at their subband
111     * index, and not in the subband order starting from 0. For instance, if
112     * resolution level 3, the first subband has the index 16, then the step
113     * of the subband is nStep[3][16], not nStep[3][0].
114     *
115     * @see Subband
116     * */
117    public float nStep[][];
118
119    /**
120     * Returns the type of the dequantizer for which the parameters are. The
121     * types are defined in the Dequantizer class.
122     *
123     * @return The type of the dequantizer for which the parameters
124     * are. Always Q_TYPE_SCALAR_DZ.
125     *
126     * @see Dequantizer
127     * */
128    public int getDequantizerType() {
129        return QuantizationType.Q_TYPE_SCALAR_DZ;
130    }
131
132}