001: /*
002: * $RCSfile: Dequantizer.java,v $
003: * $Revision: 1.1 $
004: * $Date: 2005/02/11 05:02:18 $
005: * $State: Exp $
006: *
007: * Class: Dequantizer
008: *
009: * Description: The abstract class for all 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.image.invcomptransf.*;
047: import jj2000.j2k.wavelet.synthesis.*;
048: import jj2000.j2k.entropy.decoder.*;
049: import jj2000.j2k.codestream.*;
050: import jj2000.j2k.entropy.*;
051: import jj2000.j2k.decoder.*;
052: import jj2000.j2k.wavelet.*;
053: import jj2000.j2k.image.*;
054: import jj2000.j2k.io.*;
055: import jj2000.j2k.*;
056:
057: import java.io.*;
058:
059: /**
060: * This is the abstract class from which all dequantizers must inherit. This
061: * class has the concept of a current tile and all operations are performed on
062: * the current tile.
063: *
064: * <p>This class provides default implemenations for most of the methods
065: * (wherever it makes sense), under the assumption that the image and
066: * component dimensions, and the tiles, are not modifed by the dequantizer. If
067: * that is not the case for a particular implementation then the methods
068: * should be overriden.</p>
069: *
070: * <p>Sign magnitude representation is used (instead of two's complement) for
071: * the input data. The most significant bit is used for the sign (0 if
072: * positive, 1 if negative). Then the magnitude of the quantized coefficient
073: * is stored in the next most significat bits. The most significant magnitude
074: * bit corresponds to the most significant bit-plane and so on.</p>
075: *
076: * <p>The output data is either in floating-point, or in fixed-point two's
077: * complement. In case of floating-point data the the value returned by
078: * getFixedPoint() must be 0. If the case of fixed-point data the number of
079: * fractional bits must be defined at the constructor of the implementing
080: * class and all operations must be performed accordingly. Each component may
081: * have a different number of fractional bits.</p>
082: * */
083: public abstract class Dequantizer extends MultiResImgDataAdapter
084: implements CBlkWTDataSrcDec {
085:
086: /** The prefix for dequantizer options: 'Q' */
087: public final static char OPT_PREFIX = 'Q';
088:
089: /** The list of parameters that is accepted by the bit stream
090: * readers. They start with 'Q' */
091: private static final String[][] pinfo = null;
092:
093: /** The entropy decoder from where to get the quantized data (the
094: * source). */
095: protected CBlkQuantDataSrcDec src;
096:
097: /** The "range bits" for each transformed component */
098: protected int rb[] = null;
099:
100: /** The "range bits" for each un-transformed component */
101: protected int utrb[] = null;
102:
103: /** The inverse component transformation specifications */
104: private CompTransfSpec cts;
105:
106: /** Reference to the wavelet filter specifications */
107: private SynWTFilterSpec wfs;
108:
109: /**
110: * Initializes the source of compressed data.
111: *
112: * @param src From where to obtain the quantized data.
113: *
114: * @param rb The number of "range bits" for each component (must be the
115: * "range bits" of the un-transformed components. For a definition of
116: * "range bits" see the getNomRangeBits() method.
117: *
118: * @see #getNomRangeBits
119: * */
120: public Dequantizer(CBlkQuantDataSrcDec src, int utrb[],
121: DecoderSpecs decSpec) {
122: super (src);
123: if (utrb.length != src.getNumComps()) {
124: throw new IllegalArgumentException();
125: }
126: this .src = src;
127: this .utrb = utrb;
128: this .cts = decSpec.cts;
129: this .wfs = decSpec.wfs;
130: }
131:
132: /**
133: * Returns the number of bits, referred to as the "range bits",
134: * corresponding to the nominal range of the data in the specified
135: * component.
136: *
137: * <p>The returned value corresponds to the nominal dynamic range of the
138: * reconstructed image data, not of the wavelet coefficients
139: * themselves. This is because different subbands have different gains and
140: * thus different nominal ranges. To have an idea of the nominal range in
141: * each subband the subband analysis gain value from the subband tree
142: * structure, returned by the getSynSubbandTree() method, can be used. See
143: * the Subband class for more details.</p>
144: *
145: * <p>If this number is <i>b</b> then for unsigned data the nominal range
146: * is between 0 and 2^b-1, and for signed data it is between -2^(b-1) and
147: * 2^(b-1)-1.</p>
148: *
149: * @param c The index of the component
150: *
151: * @return The number of bits corresponding to the nominal range of the
152: * data.
153: *
154: * @see Subband
155: * */
156: public int getNomRangeBits(int c) {
157: return rb[c];
158: }
159:
160: /**
161: * Returns the subband tree, for the specified tile-component. This method
162: * returns the root element of the subband tree structure, see Subband and
163: * SubbandSyn. The tree comprises all the available resolution levels.
164: *
165: * <P>The number of magnitude bits ('magBits' member variable) for each
166: * subband may have not been not initialized (it depends on the actual
167: * dequantizer and its implementation). However, they are not necessary
168: * for the subsequent steps in the decoder chain.
169: *
170: * @param t The index of the tile, from 0 to T-1.
171: *
172: * @param c The index of the component, from 0 to C-1.
173: *
174: * @return The root of the tree structure.
175: * */
176: public SubbandSyn getSynSubbandTree(int t, int c) {
177: return src.getSynSubbandTree(t, c);
178: }
179:
180: /**
181: * Returns the horizontal code-block partition origin. Allowable values
182: * are 0 and 1, nothing else.
183: * */
184: public int getCbULX() {
185: return src.getCbULX();
186: }
187:
188: /**
189: * Returns the vertical code-block partition origin. Allowable values are
190: * 0 and 1, nothing else.
191: * */
192: public int getCbULY() {
193: return src.getCbULY();
194: }
195:
196: /**
197: * Returns the parameters that are used in this class and
198: * implementing classes. It returns a 2D String array. Each of the
199: * 1D arrays is for a different option, and they have 3
200: * elements. The first element is the option name, the second one
201: * is the synopsis and the third one is a long description of what
202: * the parameter is. The synopsis or description may be 'null', in
203: * which case it is assumed that there is no synopsis or
204: * description of the option, respectively. Null may be returned
205: * if no options are supported.
206: *
207: * @return the options name, their synopsis and their explanation,
208: * or null if no options are supported.
209: * */
210: public static String[][] getParameterInfo() {
211: return pinfo;
212: }
213:
214: /**
215: * Changes the current tile, given the new indexes. An
216: * IllegalArgumentException is thrown if the indexes do not
217: * correspond to a valid tile.
218: *
219: * <P>This default implementation changes the tile in the source
220: * and re-initializes properly component transformation variables..
221: *
222: * @param x The horizontal index of the tile.
223: *
224: * @param y The vertical index of the new tile.
225: * */
226: public void setTile(int x, int y) {
227: src.setTile(x, y);
228: tIdx = getTileIdx(); // index of the current tile
229:
230: // initializations
231: int cttype = 0;
232: if (((Integer) cts.getTileDef(tIdx)).intValue() == InvCompTransf.NONE)
233: cttype = InvCompTransf.NONE;
234: else {
235: int nc = src.getNumComps() > 3 ? 3 : src.getNumComps();
236: int rev = 0;
237: for (int c = 0; c < nc; c++)
238: rev += (wfs.isReversible(tIdx, c) ? 1 : 0);
239: if (rev == 3) {
240: // All WT are reversible
241: cttype = InvCompTransf.INV_RCT;
242: } else if (rev == 0) {
243: // All WT irreversible
244: cttype = InvCompTransf.INV_ICT;
245: } else {
246: // Error
247: throw new IllegalArgumentException(
248: "Wavelet transformation " + "and "
249: + "component transformation"
250: + " not coherent in tile" + tIdx);
251: }
252: }
253:
254: switch (cttype) {
255: case InvCompTransf.NONE:
256: rb = utrb;
257: break;
258: case InvCompTransf.INV_RCT:
259: rb = InvCompTransf.calcMixedBitDepths(utrb,
260: InvCompTransf.INV_RCT, null);
261: break;
262: case InvCompTransf.INV_ICT:
263: rb = InvCompTransf.calcMixedBitDepths(utrb,
264: InvCompTransf.INV_ICT, null);
265: break;
266: default:
267: throw new IllegalArgumentException("Non JPEG 2000 part I "
268: + "component" + " transformation for tile: " + tIdx);
269: }
270: }
271:
272: /**
273: * Advances to the next tile, in standard scan-line order (by rows then
274: * columns). An NoNextElementException is thrown if the current tile is
275: * the last one (i.e. there is no next tile).
276: *
277: * <P>This default implementation just advances to the next tile in the
278: * source and re-initializes properly component transformation variables.
279: * */
280: public void nextTile() {
281: src.nextTile();
282: tIdx = getTileIdx(); // index of the current tile
283:
284: // initializations
285: int cttype = ((Integer) cts.getTileDef(tIdx)).intValue();
286: switch (cttype) {
287: case InvCompTransf.NONE:
288: rb = utrb;
289: break;
290: case InvCompTransf.INV_RCT:
291: rb = InvCompTransf.calcMixedBitDepths(utrb,
292: InvCompTransf.INV_RCT, null);
293: break;
294: case InvCompTransf.INV_ICT:
295: rb = InvCompTransf.calcMixedBitDepths(utrb,
296: InvCompTransf.INV_ICT, null);
297: break;
298: default:
299: throw new IllegalArgumentException("Non JPEG 2000 part I "
300: + "component" + " transformation for tile: " + tIdx);
301: }
302: }
303:
304: }
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