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1 vero 1 /*
2 * CVS identifier:
3 *
4 * $Id: Subband.java,v 1.47 2001/10/18 14:27:14 grosbois Exp $
5 *
6 * Class: Subband
7 *
8 * Description: Asbtract element for a tree strcuture for
9 * a description of subbands.
10 *
11 *
12 *
13 * COPYRIGHT:
14 *
15 * This software module was originally developed by Raphaël Grosbois and
16 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
17 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
18 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
19 * Centre France S.A) in the course of development of the JPEG2000
20 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
21 * software module is an implementation of a part of the JPEG 2000
22 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
23 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
24 * Partners) agree not to assert against ISO/IEC and users of the JPEG
25 * 2000 Standard (Users) any of their rights under the copyright, not
26 * including other intellectual property rights, for this software module
27 * with respect to the usage by ISO/IEC and Users of this software module
28 * or modifications thereof for use in hardware or software products
29 * claiming conformance to the JPEG 2000 Standard. Those intending to use
30 * this software module in hardware or software products are advised that
31 * their use may infringe existing patents. The original developers of
32 * this software module, JJ2000 Partners and ISO/IEC assume no liability
33 * for use of this software module or modifications thereof. No license
34 * or right to this software module is granted for non JPEG 2000 Standard
35 * conforming products. JJ2000 Partners have full right to use this
36 * software module for his/her own purpose, assign or donate this
37 * software module to any third party and to inhibit third parties from
38 * using this software module for non JPEG 2000 Standard conforming
39 * products. This copyright notice must be included in all copies or
40 * derivative works of this software module.
41 *
42 * Copyright (c) 1999/2000 JJ2000 Partners.
43 * */
44 using System;
45 using CSJ2K.j2k.image;
46 namespace CSJ2K.j2k.wavelet
47 {
48  
49 /// <summary> This abstract class represents a subband in a bidirectional tree structure
50 /// that describes the subband decomposition for a wavelet transform. This
51 /// class is implemented by the SubbandAn and SubbandSyn classes, which are for
52 /// the analysis and synthesis sides respectively.
53 ///
54 /// <p>The element can be either a node or a leaf of the tree. If it is a node,
55 /// it has 4 descendants (LL, HL, LH and HH). If it is a leaf, it has no
56 /// descendant.</p>
57 ///
58 /// <p>The tree is bidirectional. Each element in the tree structure has a
59 /// "parent", which is the subband from which the element was obtained by
60 /// decomposition. The only exception is the root element which, for obvious
61 /// reasons, has no parent (i.e. it is null).</p>
62 ///
63 /// </summary>
64 /// <seealso cref="jj2000.j2k.wavelet.analysis.SubbandAn">
65 /// </seealso>
66 /// <seealso cref="jj2000.j2k.wavelet.synthesis.SubbandSyn">
67 ///
68 /// </seealso>
69 public abstract class Subband
70 {
71 /// <summary> Returns the parent of this subband. The parent of a subband is the
72 /// subband from which this one was obtained by decomposition. The root
73 /// element has no parent subband (null).
74 ///
75 /// </summary>
76 /// <returns> The parent subband, or null for the root one.
77 ///
78 /// </returns>
79 public abstract Subband Parent{get;}
80 /// <summary> Returns the LL child subband of this subband.
81 ///
82 /// </summary>
83 /// <returns> The LL child subband, or null if there are no childs.
84 ///
85 /// </returns>
86 public abstract Subband LL{get;}
87 /// <summary> Returns the HL (horizontal high-pass) child subband of this subband.
88 ///
89 /// </summary>
90 /// <returns> The HL child subband, or null if there are no childs.
91 ///
92 /// </returns>
93 public abstract Subband HL{get;}
94 /// <summary> Returns the LH (vertical high-pass) child subband of this subband.
95 ///
96 /// </summary>
97 /// <returns> The LH child subband, or null if there are no childs.
98 ///
99 /// </returns>
100 public abstract Subband LH{get;}
101 /// <summary> Returns the HH child subband of this subband.
102 ///
103 /// </summary>
104 /// <returns> The HH child subband, or null if there are no childs.
105 ///
106 /// </returns>
107 public abstract Subband HH{get;}
108 /// <summary> Returns the first leaf subband element in the next higher resolution
109 /// level.
110 ///
111 /// </summary>
112 /// <returns> The first leaf element in the next higher resolution level, or
113 /// null if there is no higher resolution level.
114 ///
115 /// </returns>
116 virtual public Subband NextResLevel
117 {
118 get
119 {
120 Subband sb;
121  
122 if (level == 0)
123 {
124 // No higher res. level
125 return null;
126 }
127 // Go up until we get to a different resolution level
128 sb = this;
129 do
130 {
131 sb = sb.Parent;
132 if (sb == null)
133 {
134 // No higher resolution level
135 return null;
136 }
137 }
138 while (sb.resLvl == resLvl);
139 // Now go down to HL, which is in next higher resolution level
140 sb = sb.HL;
141 // Now go down LL until get to a leaf
142 while (sb.isNode)
143 {
144 sb = sb.LL;
145 }
146 return sb;
147 }
148  
149 }
150 /// <summary> This function returns the horizontal wavelet filter relevant to this
151 /// subband
152 ///
153 /// </summary>
154 /// <returns> The horizontal wavelet filter
155 ///
156 /// </returns>
157 public abstract WaveletFilter HorWFilter{get;}
158 /// <summary> This function returns the vertical wavelet filter relevant to this
159 /// subband
160 ///
161 /// </summary>
162 /// <returns> The vertical wavelet filter
163 ///
164 /// </returns>
165 public abstract WaveletFilter VerWFilter{get;}
166  
167 /// <summary>The ID for the LL orientation </summary>
168 public const int WT_ORIENT_LL = 0;
169  
170 /// <summary>The ID for the HL (horizontal high-pass) orientation </summary>
171 public const int WT_ORIENT_HL = 1;
172  
173 /// <summary>The ID for the LH (vertical high-pass) orientation </summary>
174 public const int WT_ORIENT_LH = 2;
175  
176 /// <summary>The ID for the HH orientation </summary>
177 public const int WT_ORIENT_HH = 3;
178  
179 /// <summary>True if it is a node in the tree, false if it is a leaf. </summary>
180 public bool isNode;
181  
182 /// <summary>The orientation of this subband (WT_ORIENT_LL, WT_ORIENT_HL,
183 /// WT_ORIENT_LH, WT_ORIENT_HH).
184 /// </summary>
185 public int orientation;
186  
187 /// <summary>The level in the tree to which this subband belongs, which is the
188 /// number of performed wavelet decompositions to get this subband. It is 0
189 /// for the top-level (i.e. root) node.
190 /// </summary>
191 public int level;
192  
193 /// <summary>The resolution level to which this subband contributes. 0 is the
194 /// smallest resolution level (the one with the lowest frequency LL
195 /// subband).
196 /// </summary>
197 public int resLvl;
198  
199 /// <summary>The number of code-blocks (in both directions) contained in this
200 /// subband.
201 /// </summary>
202 public Coord numCb = null;
203  
204 /// <summary> The base 2 exponent of the analysis gain of the subband. The analysis
205 /// gain of a subband is defined as the gain of the previous subband
206 /// (i.e. the one from which this one was obtained) multiplied by the line
207 /// gain and by the column gain. The line (column) gain is the gain of the
208 /// line (column) filter that was used to obtain it, which is the DC gain
209 /// for a low-pass filter and the Nyquist gain for a high-pass filter. It
210 /// is 0 by default.
211 ///
212 /// <p>Using the base 2 exponent of the value contrains the possible gains
213 /// to powers of 2. However this is perfectly compatible to the filter
214 /// normalization policy assumed here. See the split() method for more
215 /// details.</p>
216 ///
217 /// </summary>
218 /// <seealso cref="split">
219 ///
220 /// </seealso>
221 public int anGainExp;
222  
223 /// <summary> The subband index within its resolution level. This value uniquely
224 /// identifies a subband within a resolution level and a decomposition
225 /// level within it. Note that only leaf elements represent "real"
226 /// subbands, while node elements represent only intermediate stages.
227 ///
228 /// <p>It is defined recursively. The root node gets a value of 0. For a
229 /// given node, with a subband index 'b', its LL descendant gets 4*b, its
230 /// HL descendant 4*b+1, its LH descendant 4*b+2, and its HH descendant
231 /// 4*b+3, for their subband indexes.</p>
232 ///
233 /// </summary>
234 public int sbandIdx = 0;
235  
236 /// <summary> The horizontal coordinate of the upper-left corner of the subband, with
237 /// respect to the canvas origin, in the component's grid and subband's
238 /// decomposition level. This is the real horizontal index of the first
239 /// column of this subband. If even the horizontal decomposition of this
240 /// subband should be done with the low-pass-first convention. If odd it
241 /// should be done with the high-pass-first convention.
242 ///
243 /// </summary>
244 public int ulcx;
245  
246 /// <summary> The vertical coordinate of the upper-left corner of the subband, with
247 /// respect to the canvas origin, in the component's grid and subband's
248 /// decomposition level. This is the real vertical index of the first
249 /// column of this subband. If even the vertical decomposition of this
250 /// subband should be done with the low-pass-first convention. If odd it
251 /// should be done with the high-pass-first convention.
252 ///
253 /// </summary>
254 public int ulcy;
255  
256 /// <summary>The horizontal coordinate of the upper-left corner of the subband </summary>
257 public int ulx;
258  
259 /// <summary>The vertical coordinate of the upper-left corner of the subband </summary>
260 public int uly;
261  
262 /// <summary>The width of the subband </summary>
263 public int w;
264  
265 /// <summary>The height of the subband </summary>
266 public int h;
267  
268 /// <summary>The nominal code-block width </summary>
269 public int nomCBlkW;
270  
271 /// <summary>The nominal code-block height </summary>
272 public int nomCBlkH;
273  
274 /// <summary> Splits the current subband in its four subbands. This creates the four
275 /// childs (LL, HL, LH and HH) and converts the leaf in a node.
276 ///
277 /// </summary>
278 /// <param name="hfilter">The horizontal wavelet filter used to decompose this
279 /// subband.
280 ///
281 /// </param>
282 /// <param name="vfilter">The vertical wavelet filter used to decompose this
283 /// subband.
284 ///
285 /// </param>
286 /// <returns> A reference to the LL leaf (getLL()).
287 ///
288 /// </returns>
289 protected internal abstract Subband split(WaveletFilter hfilter, WaveletFilter vfilter);
290  
291 /// <summary> Initializes the childs of this node with the correct values. The sizes
292 /// of the child subbands are calculated by taking into account the
293 /// position of the subband in the canvas.
294 ///
295 /// <p>For the analysis subband gain calculation it is assumed that
296 /// analysis filters are normalized with a DC gain of 1 and a Nyquist gain
297 /// of 2.</p>
298 ///
299 /// </summary>
300 protected internal virtual void initChilds()
301 {
302 Subband subb_LL = LL;
303 Subband subb_HL = HL;
304 Subband subb_LH = LH;
305 Subband subb_HH = HH;
306  
307 // LL subband
308 subb_LL.level = level + 1;
309 subb_LL.ulcx = (ulcx + 1) >> 1;
310 subb_LL.ulcy = (ulcy + 1) >> 1;
311 subb_LL.ulx = ulx;
312 subb_LL.uly = uly;
313 subb_LL.w = ((ulcx + w + 1) >> 1) - subb_LL.ulcx;
314 subb_LL.h = ((ulcy + h + 1) >> 1) - subb_LL.ulcy;
315 // If this subband in in the all LL path (i.e. it's global orientation
316 // is LL) then child LL band contributes to a lower resolution level.
317 subb_LL.resLvl = (orientation == WT_ORIENT_LL)?resLvl - 1:resLvl;
318 subb_LL.anGainExp = anGainExp;
319 subb_LL.sbandIdx = (sbandIdx << 2);
320 // HL subband
321 subb_HL.orientation = WT_ORIENT_HL;
322 subb_HL.level = subb_LL.level;
323 subb_HL.ulcx = ulcx >> 1;
324 subb_HL.ulcy = subb_LL.ulcy;
325 subb_HL.ulx = ulx + subb_LL.w;
326 subb_HL.uly = uly;
327 subb_HL.w = ((ulcx + w) >> 1) - subb_HL.ulcx;
328 subb_HL.h = subb_LL.h;
329 subb_HL.resLvl = resLvl;
330 subb_HL.anGainExp = anGainExp + 1;
331 subb_HL.sbandIdx = (sbandIdx << 2) + 1;
332 // LH subband
333 subb_LH.orientation = WT_ORIENT_LH;
334 subb_LH.level = subb_LL.level;
335 subb_LH.ulcx = subb_LL.ulcx;
336 subb_LH.ulcy = ulcy >> 1;
337 subb_LH.ulx = ulx;
338 subb_LH.uly = uly + subb_LL.h;
339 subb_LH.w = subb_LL.w;
340 subb_LH.h = ((ulcy + h) >> 1) - subb_LH.ulcy;
341 subb_LH.resLvl = resLvl;
342 subb_LH.anGainExp = anGainExp + 1;
343 subb_LH.sbandIdx = (sbandIdx << 2) + 2;
344 // HH subband
345 subb_HH.orientation = WT_ORIENT_HH;
346 subb_HH.level = subb_LL.level;
347 subb_HH.ulcx = subb_HL.ulcx;
348 subb_HH.ulcy = subb_LH.ulcy;
349 subb_HH.ulx = subb_HL.ulx;
350 subb_HH.uly = subb_LH.uly;
351 subb_HH.w = subb_HL.w;
352 subb_HH.h = subb_LH.h;
353 subb_HH.resLvl = resLvl;
354 subb_HH.anGainExp = anGainExp + 2;
355 subb_HH.sbandIdx = (sbandIdx << 2) + 3;
356 }
357  
358 /// <summary> Creates a Subband element with all the default values. The dimensions
359 /// are (0,0), the upper left corner is (0,0) and the upper-left corner
360 /// with respect to the canvas is (0,0) too.
361 ///
362 /// </summary>
363 public Subband()
364 {
365 }
366  
367 /// <summary> Creates the top-level node and the entire subband tree, with the
368 /// top-level dimensions, the number of decompositions, and the
369 /// decomposition tree as specified.
370 ///
371 /// <p>For the analysis subband gain calculation it is assumed that
372 /// analysis filters are normalized with a DC gain of 1 and a Nyquist gain
373 /// of 2.</p>
374 ///
375 /// <p>This constructor does not initialize the value of the magBits member
376 /// variable. This variable is normally initialized by the quantizer, on
377 /// the encoder side, or the bit stream reader, on the decoder side.</p>
378 ///
379 /// </summary>
380 /// <param name="w">The top-level width
381 ///
382 /// </param>
383 /// <param name="h">The top-level height
384 ///
385 /// </param>
386 /// <param name="ulcx">The horizontal coordinate of the upper-left corner with
387 /// respect to the canvas origin, in the component grid.
388 ///
389 /// </param>
390 /// <param name="ulcy">The vertical coordinate of the upper-left corner with
391 /// respect to the canvas origin, in the component grid.
392 ///
393 /// </param>
394 /// <param name="lvls">The number of levels (or LL decompositions) in the tree.
395 ///
396 /// </param>
397 /// <param name="hfilters">The horizontal wavelet filters (analysis or synthesis)
398 /// for each resolution level, starting at resolution level 0. If there are
399 /// less elements in the array than there are resolution levels, the last
400 /// element is used for the remaining resolution levels.
401 ///
402 /// </param>
403 /// <param name="vfilters">The vertical wavelet filters (analysis or synthesis)
404 /// for each resolution level, starting at resolution level 0. If there are
405 /// less elements in the array than there are resolution levels, the last
406 /// element is used for the remaining resolution levels.
407 ///
408 /// </param>
409 /// <seealso cref="WaveletTransform">
410 ///
411 /// </seealso>
412 public Subband(int w, int h, int ulcx, int ulcy, int lvls, WaveletFilter[] hfilters, WaveletFilter[] vfilters)
413 {
414 int i, hi, vi;
415 Subband cur; // The current subband
416  
417 // Initialize top-level node
418 this.w = w;
419 this.h = h;
420 this.ulcx = ulcx;
421 this.ulcy = ulcy;
422 this.resLvl = lvls;
423 // First create dyadic decomposition.
424 cur = this;
425 for (i = 0; i < lvls; i++)
426 {
427 hi = (cur.resLvl <= hfilters.Length)?cur.resLvl - 1:hfilters.Length - 1;
428 vi = (cur.resLvl <= vfilters.Length)?cur.resLvl - 1:vfilters.Length - 1;
429 cur = cur.split(hfilters[hi], vfilters[vi]);
430 }
431 }
432  
433 /// <summary> Returns the next subband in the same resolution level, following the
434 /// subband index order. If already at the last subband then null is
435 /// returned. If this subband is not a leaf an IllegalArgumentException is
436 /// thrown.
437 ///
438 /// </summary>
439 /// <returns> The next subband in the same resolution level, following the
440 /// subband index order, or null if already at last subband.
441 ///
442 /// </returns>
443 public virtual Subband nextSubband()
444 {
445 Subband sb;
446  
447 if (isNode)
448 {
449 throw new System.ArgumentException();
450 }
451  
452 switch (orientation)
453 {
454  
455 case WT_ORIENT_LL:
456 sb = Parent;
457 if (sb == null || sb.resLvl != resLvl)
458 {
459 // Already at top-level or last subband in res. level
460 return null;
461 }
462 else
463 {
464 return sb.HL;
465 }
466 //goto case WT_ORIENT_HL;
467  
468 case WT_ORIENT_HL:
469 return Parent.LH;
470  
471 case WT_ORIENT_LH:
472 return Parent.HH;
473  
474 case WT_ORIENT_HH:
475 // This is the complicated one
476 sb = this;
477 while (sb.orientation == WT_ORIENT_HH)
478 {
479 sb = sb.Parent;
480 }
481 switch (sb.orientation)
482 {
483  
484 case WT_ORIENT_LL:
485 sb = sb.Parent;
486 if (sb == null || sb.resLvl != resLvl)
487 {
488 // Already at top-level or last subband in res. level
489 return null;
490 }
491 else
492 {
493 sb = sb.HL;
494 }
495 break;
496  
497 case WT_ORIENT_HL:
498 sb = sb.Parent.LH;
499 break;
500  
501 case WT_ORIENT_LH:
502 sb = sb.Parent.HH;
503 break;
504  
505 default:
506 throw new System.ApplicationException("You have found a bug in JJ2000");
507  
508 }
509 while (sb.isNode)
510 {
511 sb = sb.LL;
512 }
513 return sb;
514  
515 default:
516 throw new System.ApplicationException("You have found a bug in JJ2000");
517  
518 }
519 }
520  
521 /// <summary> Returns a subband element in the tree, given its resolution level and
522 /// subband index. This method searches through the tree.
523 ///
524 /// </summary>
525 /// <param name="rl">The resolution level.
526 ///
527 /// </param>
528 /// <param name="sbi">The subband index, within the resolution level.
529 ///
530 /// </param>
531 public virtual Subband getSubbandByIdx(int rl, int sbi)
532 {
533 Subband sb = this;
534  
535 // Find the root subband for the resolution level
536 if (rl > sb.resLvl || rl < 0)
537 {
538 throw new System.ArgumentException("Resolution level index " + "out of range");
539 }
540  
541 // Returns directly if it is itself
542 if (rl == sb.resLvl && sbi == sb.sbandIdx)
543 return sb;
544  
545 if (sb.sbandIdx != 0)
546 sb = sb.Parent;
547  
548 while (sb.resLvl > rl)
549 sb = sb.LL;
550 while (sb.resLvl < rl)
551 sb = sb.Parent;
552  
553 switch (sbi)
554 {
555  
556 case 0:
557 default:
558 return sb;
559  
560 case 1:
561 return sb.HL;
562  
563 case 2:
564 return sb.LH;
565  
566 case 3:
567 return sb.HH;
568 }
569 }
570  
571 /// <summary> Returns a reference to the Subband element to which the specified point
572 /// belongs. The specified point must be inside this (i.e. the one defined
573 /// by this object) subband. This method searches through the tree.
574 ///
575 /// </summary>
576 /// <param name="x">horizontal coordinate of the specified point.
577 ///
578 /// </param>
579 /// <param name="y">horizontal coordinate of the specified point.
580 ///
581 /// </param>
582 public virtual Subband getSubband(int x, int y)
583 {
584 Subband cur, hhs;
585  
586 // Check that we are inside this subband
587 if (x < ulx || y < uly || x >= ulx + w || y >= uly + h)
588 {
589 throw new System.ArgumentException();
590 }
591  
592 cur = this;
593 while (cur.isNode)
594 {
595 hhs = cur.HH;
596 // While we are still at a node -> continue
597 if (x < hhs.ulx)
598 {
599 // Is the result of horizontal low-pass
600 if (y < hhs.uly)
601 {
602 // Vertical low-pass
603 cur = cur.LL;
604 }
605 else
606 {
607 // Vertical high-pass
608 cur = cur.LH;
609 }
610 }
611 else
612 {
613 // Is the result of horizontal high-pass
614 if (y < hhs.uly)
615 {
616 // Vertical low-pass
617 cur = cur.HL;
618 }
619 else
620 {
621 // Vertical high-pass
622 cur = cur.HH;
623 }
624 }
625 }
626  
627 return cur;
628 }
629  
630 /// <summary> Returns subband informations in a string.
631 ///
632 /// </summary>
633 /// <returns> Subband informations
634 ///
635 /// </returns>
636 public override System.String ToString()
637 {
638 System.String string_Renamed = "w=" + w + ",h=" + h + ",ulx=" + ulx + ",uly=" + uly + ",ulcx=" + ulcx + ",ulcy=" + ulcy + ",idx=" + sbandIdx + ",orient=" + orientation + ",node=" + isNode + ",level=" + level + ",resLvl=" + resLvl + ",nomCBlkW=" + nomCBlkW + ",nomCBlkH=" + nomCBlkH + ",numCb=" + numCb;
639  
640 return string_Renamed;
641 }
642 }
643 }