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: */
044: package jj2000.j2k.quantization.dequantizer;
045:
046: import jj2000.j2k.io.*;
047: import jj2000.j2k.wavelet.*;
048: import jj2000.j2k.quantization.*;
049: import jj2000.j2k.entropy.decoder.*;
050: import jj2000.j2k.image.*;
051: import jj2000.j2k.util.*;
052: import jj2000.j2k.codestream.*;
053: import jj2000.j2k.codestream.reader.*;
054:
055: import 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: * */
064: public 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: }
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