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41 
42 /************************************************************************************\
43     This is improved variant of chessboard corner detection algorithm that
44     uses a graph of connected quads. It is based on the code contributed
45     by Vladimir Vezhnevets and Philip Gruebele.
46     Here is the copyright notice from the original Vladimir's code:
47     ===============================================================
48 
49     The algorithms developed and implemented by Vezhnevets Vldimir
50     aka Dead Moroz (vvp@graphics.cs.msu.ru)
51     See http://graphics.cs.msu.su/en/research/calibration/opencv.html
52     for detailed information.
53 
54     Reliability additions and modifications made by Philip Gruebele.
55     <a href="mailto:pgruebele@cox.net">pgruebele@cox.net</a>
56 
57     Some further improvements for detection of partially ocluded boards at non-ideal
58     lighting conditions have been made by Alex Bovyrin and Kurt Kolonige
59 
60 \************************************************************************************/
61 
62 #include "precomp.hpp"
63 #include "opencv2/imgproc/imgproc_c.h"
64 #include "opencv2/calib3d/calib3d_c.h"
65 #include "circlesgrid.hpp"
66 #include <stdarg.h>
67 
68 //#define ENABLE_TRIM_COL_ROW
69 
70 //#define DEBUG_CHESSBOARD
71 #ifdef DEBUG_CHESSBOARD
72 #  include "opencv2/opencv_modules.hpp"
73 #  ifdef HAVE_OPENCV_HIGHGUI
74 #    include "opencv2/highgui.hpp"
75 #  else
76 #    undef DEBUG_CHESSBOARD
77 #  endif
78 #endif
79 #ifdef DEBUG_CHESSBOARD
PRINTF(const char * fmt,...)80 static int PRINTF( const char* fmt, ... )
81 {
82     va_list args;
83     va_start(args, fmt);
84     return vprintf(fmt, args);
85 }
86 #else
PRINTF(const char *,...)87 static int PRINTF( const char*, ... )
88 {
89     return 0;
90 }
91 #endif
92 
93 
94 //=====================================================================================
95 // Implementation for the enhanced calibration object detection
96 //=====================================================================================
97 
98 #define MAX_CONTOUR_APPROX  7
99 
100 struct CvContourEx
101 {
102     CV_CONTOUR_FIELDS()
103     int counter;
104 };
105 
106 //=====================================================================================
107 
108 /// Corner info structure
109 /** This structure stores information about the chessboard corner.*/
110 struct CvCBCorner
111 {
112     CvPoint2D32f pt; // Coordinates of the corner
113     int row;         // Board row index
114     int count;       // Number of neighbor corners
115     struct CvCBCorner* neighbors[4]; // Neighbor corners
116 
meanDistCvCBCorner117     float meanDist(int *_n) const
118     {
119         float sum = 0;
120         int n = 0;
121         for( int i = 0; i < 4; i++ )
122         {
123             if( neighbors[i] )
124             {
125                 float dx = neighbors[i]->pt.x - pt.x;
126                 float dy = neighbors[i]->pt.y - pt.y;
127                 sum += sqrt(dx*dx + dy*dy);
128                 n++;
129             }
130         }
131         if(_n)
132             *_n = n;
133         return sum/MAX(n,1);
134     }
135 };
136 
137 //=====================================================================================
138 /// Quadrangle contour info structure
139 /** This structure stores information about the chessboard quadrange.*/
140 struct CvCBQuad
141 {
142     int count;      // Number of quad neighbors
143     int group_idx;  // quad group ID
144     int row, col;   // row and column of this quad
145     bool ordered;   // true if corners/neighbors are ordered counter-clockwise
146     float edge_len; // quad edge len, in pix^2
147     // neighbors and corners are synced, i.e., neighbor 0 shares corner 0
148     CvCBCorner *corners[4]; // Coordinates of quad corners
149     struct CvCBQuad *neighbors[4]; // Pointers of quad neighbors
150 };
151 
152 //=====================================================================================
153 
154 //static CvMat* debug_img = 0;
155 
156 static int icvGenerateQuads( CvCBQuad **quads, CvCBCorner **corners,
157                              CvMemStorage *storage, CvMat *image, int flags );
158 
159 /*static int
160 icvGenerateQuadsEx( CvCBQuad **out_quads, CvCBCorner **out_corners,
161     CvMemStorage *storage, CvMat *image, CvMat *thresh_img, int dilation, int flags );*/
162 
163 static void icvFindQuadNeighbors( CvCBQuad *quads, int quad_count );
164 
165 static int icvFindConnectedQuads( CvCBQuad *quads, int quad_count,
166                                   CvCBQuad **quad_group, int group_idx,
167                                   CvMemStorage* storage );
168 
169 static int icvCheckQuadGroup( CvCBQuad **quad_group, int count,
170                               CvCBCorner **out_corners, CvSize pattern_size );
171 
172 static int icvCleanFoundConnectedQuads( int quad_count,
173                 CvCBQuad **quads, CvSize pattern_size );
174 
175 static int icvOrderFoundConnectedQuads( int quad_count, CvCBQuad **quads,
176            int *all_count, CvCBQuad **all_quads, CvCBCorner **corners,
177            CvSize pattern_size, CvMemStorage* storage );
178 
179 static void icvOrderQuad(CvCBQuad *quad, CvCBCorner *corner, int common);
180 
181 #ifdef ENABLE_TRIM_COL_ROW
182 static int icvTrimCol(CvCBQuad **quads, int count, int col, int dir);
183 
184 static int icvTrimRow(CvCBQuad **quads, int count, int row, int dir);
185 #endif
186 
187 static int icvAddOuterQuad(CvCBQuad *quad, CvCBQuad **quads, int quad_count,
188                     CvCBQuad **all_quads, int all_count, CvCBCorner **corners);
189 
190 static void icvRemoveQuadFromGroup(CvCBQuad **quads, int count, CvCBQuad *q0);
191 
192 static int icvCheckBoardMonotony( CvPoint2D32f* corners, CvSize pattern_size );
193 
194 #if 0
195 static void
196 icvCalcAffineTranf2D32f(CvPoint2D32f* pts1, CvPoint2D32f* pts2, int count, CvMat* affine_trans)
197 {
198     int i, j;
199     int real_count = 0;
200     for( j = 0; j < count; j++ )
201     {
202         if( pts1[j].x >= 0 ) real_count++;
203     }
204     if(real_count < 3) return;
205     cv::Ptr<CvMat> xy = cvCreateMat( 2*real_count, 6, CV_32FC1 );
206     cv::Ptr<CvMat> uv = cvCreateMat( 2*real_count, 1, CV_32FC1 );
207     //estimate affine transfromation
208     for( i = 0, j = 0; j < count; j++ )
209     {
210         if( pts1[j].x >= 0 )
211         {
212             CV_MAT_ELEM( *xy, float, i*2+1, 2 ) = CV_MAT_ELEM( *xy, float, i*2, 0 ) = pts2[j].x;
213             CV_MAT_ELEM( *xy, float, i*2+1, 3 ) = CV_MAT_ELEM( *xy, float, i*2, 1 ) = pts2[j].y;
214             CV_MAT_ELEM( *xy, float, i*2, 2 ) = CV_MAT_ELEM( *xy, float, i*2, 3 ) = CV_MAT_ELEM( *xy, float, i*2, 5 ) = \
215                 CV_MAT_ELEM( *xy, float, i*2+1, 0 ) = CV_MAT_ELEM( *xy, float, i*2+1, 1 ) = CV_MAT_ELEM( *xy, float, i*2+1, 4 ) = 0;
216             CV_MAT_ELEM( *xy, float, i*2, 4 ) = CV_MAT_ELEM( *xy, float, i*2+1, 5 ) = 1;
217             CV_MAT_ELEM( *uv, float, i*2, 0 ) = pts1[j].x;
218             CV_MAT_ELEM( *uv, float, i*2+1, 0 ) = pts1[j].y;
219             i++;
220         }
221     }
222 
223     cvSolve( xy, uv, affine_trans, CV_SVD );
224 }
225 #endif
226 
227 CV_IMPL
cvFindChessboardCorners(const void * arr,CvSize pattern_size,CvPoint2D32f * out_corners,int * out_corner_count,int flags)228 int cvFindChessboardCorners( const void* arr, CvSize pattern_size,
229                              CvPoint2D32f* out_corners, int* out_corner_count,
230                              int flags )
231 {
232     int found = 0;
233     CvCBQuad *quads = 0, **quad_group = 0;
234     CvCBCorner *corners = 0, **corner_group = 0;
235 
236     try
237     {
238     int k = 0;
239     const int min_dilations = 0;
240     const int max_dilations = 7;
241     cv::Ptr<CvMat> norm_img, thresh_img;
242 #ifdef DEBUG_CHESSBOARD
243     cv::Ptr<IplImage> dbg_img;
244     cv::Ptr<IplImage> dbg1_img;
245     cv::Ptr<IplImage> dbg2_img;
246 #endif
247     cv::Ptr<CvMemStorage> storage;
248 
249     CvMat stub, *img = (CvMat*)arr;
250 
251     int expected_corners_num = (pattern_size.width/2+1)*(pattern_size.height/2+1);
252 
253     int prev_sqr_size = 0;
254 
255     if( out_corner_count )
256         *out_corner_count = 0;
257 
258     IplImage _img;
259     int quad_count = 0, group_idx = 0, dilations = 0;
260 
261     img = cvGetMat( img, &stub );
262     //debug_img = img;
263 
264     if( CV_MAT_DEPTH( img->type ) != CV_8U || CV_MAT_CN( img->type ) == 2 )
265         CV_Error( CV_StsUnsupportedFormat, "Only 8-bit grayscale or color images are supported" );
266 
267     if( pattern_size.width <= 2 || pattern_size.height <= 2 )
268         CV_Error( CV_StsOutOfRange, "Both width and height of the pattern should have bigger than 2" );
269 
270     if( !out_corners )
271         CV_Error( CV_StsNullPtr, "Null pointer to corners" );
272 
273     storage.reset(cvCreateMemStorage(0));
274     thresh_img.reset(cvCreateMat( img->rows, img->cols, CV_8UC1 ));
275 
276 #ifdef DEBUG_CHESSBOARD
277     dbg_img = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 3 );
278     dbg1_img = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 3 );
279     dbg2_img = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 3 );
280 #endif
281 
282     if( CV_MAT_CN(img->type) != 1 || (flags & CV_CALIB_CB_NORMALIZE_IMAGE) )
283     {
284         // equalize the input image histogram -
285         // that should make the contrast between "black" and "white" areas big enough
286         norm_img.reset(cvCreateMat( img->rows, img->cols, CV_8UC1 ));
287 
288         if( CV_MAT_CN(img->type) != 1 )
289         {
290             cvCvtColor( img, norm_img, CV_BGR2GRAY );
291             img = norm_img;
292         }
293 
294         if( flags & CV_CALIB_CB_NORMALIZE_IMAGE )
295         {
296             cvEqualizeHist( img, norm_img );
297             img = norm_img;
298         }
299     }
300 
301     if( flags & CV_CALIB_CB_FAST_CHECK)
302     {
303         cvGetImage(img, &_img);
304         int check_chessboard_result = cvCheckChessboard(&_img, pattern_size);
305         if(check_chessboard_result <= 0)
306         {
307             return 0;
308         }
309     }
310 
311     // Try our standard "1" dilation, but if the pattern is not found, iterate the whole procedure with higher dilations.
312     // This is necessary because some squares simply do not separate properly with a single dilation.  However,
313     // we want to use the minimum number of dilations possible since dilations cause the squares to become smaller,
314     // making it difficult to detect smaller squares.
315     for( k = 0; k < 6; k++ )
316     {
317         for( dilations = min_dilations; dilations <= max_dilations; dilations++ )
318         {
319             if (found)
320                 break;      // already found it
321 
322             cvFree(&quads);
323             cvFree(&corners);
324 
325             /*if( k == 1 )
326             {
327                 //Pattern was not found using binarization
328                 // Run multi-level quads extraction
329                 // In case one-level binarization did not give enough number of quads
330                 CV_CALL( quad_count = icvGenerateQuadsEx( &quads, &corners, storage, img, thresh_img, dilations, flags ));
331                 PRINTF("EX quad count: %d/%d\n", quad_count, expected_corners_num);
332             }
333             else*/
334             {
335                 // convert the input grayscale image to binary (black-n-white)
336                 if( flags & CV_CALIB_CB_ADAPTIVE_THRESH )
337                 {
338                     int block_size = cvRound(prev_sqr_size == 0 ?
339                         MIN(img->cols,img->rows)*(k%2 == 0 ? 0.2 : 0.1): prev_sqr_size*2)|1;
340 
341                     // convert to binary
342                     cvAdaptiveThreshold( img, thresh_img, 255,
343                         CV_ADAPTIVE_THRESH_MEAN_C, CV_THRESH_BINARY, block_size, (k/2)*5 );
344                     if (dilations > 0)
345                         cvDilate( thresh_img, thresh_img, 0, dilations-1 );
346                 }
347                 else
348                 {
349                     // Make dilation before the thresholding.
350                     // It splits chessboard corners
351                     //cvDilate( img, thresh_img, 0, 1 );
352 
353                     // empiric threshold level
354                     double mean = cvAvg( img ).val[0];
355                     int thresh_level = cvRound( mean - 10 );
356                     thresh_level = MAX( thresh_level, 10 );
357 
358                     cvThreshold( img, thresh_img, thresh_level, 255, CV_THRESH_BINARY );
359                     cvDilate( thresh_img, thresh_img, 0, dilations );
360                 }
361 
362 #ifdef DEBUG_CHESSBOARD
363                 cvCvtColor(thresh_img,dbg_img,CV_GRAY2BGR);
364 #endif
365 
366                 // So we can find rectangles that go to the edge, we draw a white line around the image edge.
367                 // Otherwise FindContours will miss those clipped rectangle contours.
368                 // The border color will be the image mean, because otherwise we risk screwing up filters like cvSmooth()...
369                 cvRectangle( thresh_img, cvPoint(0,0), cvPoint(thresh_img->cols-1,
370                     thresh_img->rows-1), CV_RGB(255,255,255), 3, 8);
371 
372                 quad_count = icvGenerateQuads( &quads, &corners, storage, thresh_img, flags );
373 
374                 PRINTF("Quad count: %d/%d\n", quad_count, expected_corners_num);
375             }
376 
377 
378 #ifdef DEBUG_CHESSBOARD
379             cvCopy(dbg_img, dbg1_img);
380             cvNamedWindow("all_quads", 1);
381             // copy corners to temp array
382             for(int i = 0; i < quad_count; i++ )
383             {
384                 for (int k=0; k<4; k++)
385                 {
386                     CvPoint2D32f pt1, pt2;
387                     CvScalar color = CV_RGB(30,255,30);
388                     pt1 = quads[i].corners[k]->pt;
389                     pt2 = quads[i].corners[(k+1)%4]->pt;
390                     pt2.x = (pt1.x + pt2.x)/2;
391                     pt2.y = (pt1.y + pt2.y)/2;
392                     if (k>0)
393                         color = CV_RGB(200,200,0);
394                     cvLine( dbg1_img, cvPointFrom32f(pt1), cvPointFrom32f(pt2), color, 3, 8);
395                 }
396             }
397 
398 
399             cvShowImage("all_quads", (IplImage*)dbg1_img);
400             cvWaitKey();
401 #endif
402 
403             if( quad_count <= 0 )
404                 continue;
405 
406             // Find quad's neighbors
407             icvFindQuadNeighbors( quads, quad_count );
408 
409             // allocate extra for adding in icvOrderFoundQuads
410             cvFree(&quad_group);
411             cvFree(&corner_group);
412             quad_group = (CvCBQuad**)cvAlloc( sizeof(quad_group[0]) * (quad_count+quad_count / 2));
413             corner_group = (CvCBCorner**)cvAlloc( sizeof(corner_group[0]) * (quad_count+quad_count / 2)*4 );
414 
415             for( group_idx = 0; ; group_idx++ )
416             {
417                 int count = 0;
418                 count = icvFindConnectedQuads( quads, quad_count, quad_group, group_idx, storage );
419 
420                 int icount = count;
421                 if( count == 0 )
422                     break;
423 
424                 // order the quad corners globally
425                 // maybe delete or add some
426                 PRINTF("Starting ordering of inner quads\n");
427                 count = icvOrderFoundConnectedQuads(count, quad_group, &quad_count, &quads, &corners,
428                     pattern_size, storage );
429                 PRINTF("Orig count: %d  After ordering: %d\n", icount, count);
430 
431 
432 #ifdef DEBUG_CHESSBOARD
433                 cvCopy(dbg_img,dbg2_img);
434                 cvNamedWindow("connected_group", 1);
435                 // copy corners to temp array
436                 for(int i = 0; i < quad_count; i++ )
437                 {
438                     if (quads[i].group_idx == group_idx)
439                         for (int k=0; k<4; k++)
440                         {
441                             CvPoint2D32f pt1, pt2;
442                             CvScalar color = CV_RGB(30,255,30);
443                             if (quads[i].ordered)
444                                 color = CV_RGB(255,30,30);
445                             pt1 = quads[i].corners[k]->pt;
446                             pt2 = quads[i].corners[(k+1)%4]->pt;
447                             pt2.x = (pt1.x + pt2.x)/2;
448                             pt2.y = (pt1.y + pt2.y)/2;
449                             if (k>0)
450                                 color = CV_RGB(200,200,0);
451                             cvLine( dbg2_img, cvPointFrom32f(pt1), cvPointFrom32f(pt2), color, 3, 8);
452                         }
453                 }
454                 cvShowImage("connected_group", (IplImage*)dbg2_img);
455                 cvWaitKey();
456 #endif
457 
458                 if (count == 0)
459                     continue;       // haven't found inner quads
460 
461 
462                 // If count is more than it should be, this will remove those quads
463                 // which cause maximum deviation from a nice square pattern.
464                 count = icvCleanFoundConnectedQuads( count, quad_group, pattern_size );
465                 PRINTF("Connected group: %d  orig count: %d cleaned: %d\n", group_idx, icount, count);
466 
467                 count = icvCheckQuadGroup( quad_group, count, corner_group, pattern_size );
468                 PRINTF("Connected group: %d  count: %d  cleaned: %d\n", group_idx, icount, count);
469 
470                 {
471                 int n = count > 0 ? pattern_size.width * pattern_size.height : -count;
472                 n = MIN( n, pattern_size.width * pattern_size.height );
473                 float sum_dist = 0;
474                 int total = 0;
475 
476                 for(int i = 0; i < n; i++ )
477                 {
478                     int ni = 0;
479                     float avgi = corner_group[i]->meanDist(&ni);
480                     sum_dist += avgi*ni;
481                     total += ni;
482                 }
483                 prev_sqr_size = cvRound(sum_dist/MAX(total, 1));
484 
485                 if( count > 0 || (out_corner_count && -count > *out_corner_count) )
486                 {
487                     // copy corners to output array
488                     for(int i = 0; i < n; i++ )
489                         out_corners[i] = corner_group[i]->pt;
490 
491                     if( out_corner_count )
492                         *out_corner_count = n;
493 
494                     if( count == pattern_size.width*pattern_size.height &&
495                         icvCheckBoardMonotony( out_corners, pattern_size ))
496                     {
497                         found = 1;
498                         break;
499                     }
500                 }
501                 }
502             }
503         }//dilations
504     }//
505 
506     if( found )
507         found = icvCheckBoardMonotony( out_corners, pattern_size );
508 
509     // check that none of the found corners is too close to the image boundary
510     if( found )
511     {
512         const int BORDER = 8;
513         for( k = 0; k < pattern_size.width*pattern_size.height; k++ )
514         {
515             if( out_corners[k].x <= BORDER || out_corners[k].x > img->cols - BORDER ||
516                 out_corners[k].y <= BORDER || out_corners[k].y > img->rows - BORDER )
517                 break;
518         }
519 
520         found = k == pattern_size.width*pattern_size.height;
521     }
522 
523     if( found && pattern_size.height % 2 == 0 && pattern_size.width % 2 == 0 )
524     {
525         int last_row = (pattern_size.height-1)*pattern_size.width;
526         double dy0 = out_corners[last_row].y - out_corners[0].y;
527         if( dy0 < 0 )
528         {
529             int n = pattern_size.width*pattern_size.height;
530             for(int i = 0; i < n/2; i++ )
531             {
532                 CvPoint2D32f temp;
533                 CV_SWAP(out_corners[i], out_corners[n-i-1], temp);
534             }
535         }
536     }
537 
538     if( found )
539     {
540         cv::Ptr<CvMat> gray;
541         if( CV_MAT_CN(img->type) != 1 )
542         {
543             gray.reset(cvCreateMat(img->rows, img->cols, CV_8UC1));
544             cvCvtColor(img, gray, CV_BGR2GRAY);
545         }
546         else
547         {
548             gray.reset(cvCloneMat(img));
549         }
550         int wsize = 2;
551         cvFindCornerSubPix( gray, out_corners, pattern_size.width*pattern_size.height,
552             cvSize(wsize, wsize), cvSize(-1,-1), cvTermCriteria(CV_TERMCRIT_EPS+CV_TERMCRIT_ITER, 15, 0.1));
553     }
554     }
555     catch(...)
556     {
557         cvFree(&quads);
558         cvFree(&corners);
559         cvFree(&quad_group);
560         cvFree(&corner_group);
561         throw;
562     }
563 
564     cvFree(&quads);
565     cvFree(&corners);
566     cvFree(&quad_group);
567     cvFree(&corner_group);
568     return found;
569 }
570 
571 //
572 // Checks that each board row and column is pretty much monotonous curve:
573 // It analyzes each row and each column of the chessboard as following:
574 //    for each corner c lying between end points in the same row/column it checks that
575 //    the point projection to the line segment (a,b) is lying between projections
576 //    of the neighbor corners in the same row/column.
577 //
578 // This function has been created as temporary workaround for the bug in current implementation
579 // of cvFindChessboardCornes that produces absolutely unordered sets of corners.
580 //
581 
582 static int
icvCheckBoardMonotony(CvPoint2D32f * corners,CvSize pattern_size)583 icvCheckBoardMonotony( CvPoint2D32f* corners, CvSize pattern_size )
584 {
585     int i, j, k;
586 
587     for( k = 0; k < 2; k++ )
588     {
589         for( i = 0; i < (k == 0 ? pattern_size.height : pattern_size.width); i++ )
590         {
591             CvPoint2D32f a = k == 0 ? corners[i*pattern_size.width] : corners[i];
592             CvPoint2D32f b = k == 0 ? corners[(i+1)*pattern_size.width-1] :
593                 corners[(pattern_size.height-1)*pattern_size.width + i];
594             float prevt = 0, dx0 = b.x - a.x, dy0 = b.y - a.y;
595             if( fabs(dx0) + fabs(dy0) < FLT_EPSILON )
596                 return 0;
597             for( j = 1; j < (k == 0 ? pattern_size.width : pattern_size.height) - 1; j++ )
598             {
599                 CvPoint2D32f c = k == 0 ? corners[i*pattern_size.width + j] :
600                     corners[j*pattern_size.width + i];
601                 float t = ((c.x - a.x)*dx0 + (c.y - a.y)*dy0)/(dx0*dx0 + dy0*dy0);
602                 if( t < prevt || t > 1 )
603                     return 0;
604                 prevt = t;
605             }
606         }
607     }
608 
609     return 1;
610 }
611 
612 //
613 // order a group of connected quads
614 // order of corners:
615 //   0 is top left
616 //   clockwise from there
617 // note: "top left" is nominal, depends on initial ordering of starting quad
618 //   but all other quads are ordered consistently
619 //
620 // can change the number of quads in the group
621 // can add quads, so we need to have quad/corner arrays passed in
622 //
623 
624 static int
icvOrderFoundConnectedQuads(int quad_count,CvCBQuad ** quads,int * all_count,CvCBQuad ** all_quads,CvCBCorner ** corners,CvSize pattern_size,CvMemStorage * storage)625 icvOrderFoundConnectedQuads( int quad_count, CvCBQuad **quads,
626         int *all_count, CvCBQuad **all_quads, CvCBCorner **corners,
627         CvSize pattern_size, CvMemStorage* storage )
628 {
629     cv::Ptr<CvMemStorage> temp_storage(cvCreateChildMemStorage( storage ));
630     CvSeq* stack = cvCreateSeq( 0, sizeof(*stack), sizeof(void*), temp_storage );
631 
632     // first find an interior quad
633     CvCBQuad *start = NULL;
634     for (int i=0; i<quad_count; i++)
635     {
636         if (quads[i]->count == 4)
637         {
638             start = quads[i];
639             break;
640         }
641     }
642 
643     if (start == NULL)
644         return 0;   // no 4-connected quad
645 
646     // start with first one, assign rows/cols
647     int row_min = 0, col_min = 0, row_max=0, col_max = 0;
648 
649     std::map<int, int> col_hist;
650     std::map<int, int> row_hist;
651 
652     cvSeqPush(stack, &start);
653     start->row = 0;
654     start->col = 0;
655     start->ordered = true;
656 
657     // Recursively order the quads so that all position numbers (e.g.,
658     // 0,1,2,3) are in the at the same relative corner (e.g., lower right).
659 
660     while( stack->total )
661     {
662         CvCBQuad* q;
663         cvSeqPop( stack, &q );
664         int col = q->col;
665         int row = q->row;
666         col_hist[col]++;
667         row_hist[row]++;
668 
669         // check min/max
670         if (row > row_max) row_max = row;
671         if (row < row_min) row_min = row;
672         if (col > col_max) col_max = col;
673         if (col < col_min) col_min = col;
674 
675         for(int i = 0; i < 4; i++ )
676         {
677             CvCBQuad *neighbor = q->neighbors[i];
678             switch(i)   // adjust col, row for this quad
679             {           // start at top left, go clockwise
680             case 0:
681                 row--; col--; break;
682             case 1:
683                 col += 2; break;
684             case 2:
685                 row += 2;   break;
686             case 3:
687                 col -= 2; break;
688             }
689 
690             // just do inside quads
691             if (neighbor && neighbor->ordered == false && neighbor->count == 4)
692             {
693                 PRINTF("col: %d  row: %d\n", col, row);
694                 icvOrderQuad(neighbor, q->corners[i], (i+2)%4); // set in order
695                 neighbor->ordered = true;
696                 neighbor->row = row;
697                 neighbor->col = col;
698                 cvSeqPush( stack, &neighbor );
699             }
700         }
701     }
702 
703     for (int i=col_min; i<=col_max; i++)
704         PRINTF("HIST[%d] = %d\n", i, col_hist[i]);
705 
706     // analyze inner quad structure
707     int w = pattern_size.width - 1;
708     int h = pattern_size.height - 1;
709     int drow = row_max - row_min + 1;
710     int dcol = col_max - col_min + 1;
711 
712     // normalize pattern and found quad indices
713     if ((w > h && dcol < drow) ||
714         (w < h && drow < dcol))
715     {
716         h = pattern_size.width - 1;
717         w = pattern_size.height - 1;
718     }
719 
720     PRINTF("Size: %dx%d  Pattern: %dx%d\n", dcol, drow, w, h);
721 
722     // check if there are enough inner quads
723     if (dcol < w || drow < h)   // found enough inner quads?
724     {
725         PRINTF("Too few inner quad rows/cols\n");
726         return 0;   // no, return
727     }
728 #ifdef ENABLE_TRIM_COL_ROW
729     // too many columns, not very common
730     if (dcol == w+1)    // too many, trim
731     {
732         PRINTF("Trimming cols\n");
733         if (col_hist[col_max] > col_hist[col_min])
734         {
735             PRINTF("Trimming left col\n");
736             quad_count = icvTrimCol(quads,quad_count,col_min,-1);
737         }
738         else
739         {
740             PRINTF("Trimming right col\n");
741             quad_count = icvTrimCol(quads,quad_count,col_max,+1);
742         }
743     }
744 
745     // too many rows, not very common
746     if (drow == h+1)    // too many, trim
747     {
748         PRINTF("Trimming rows\n");
749         if (row_hist[row_max] > row_hist[row_min])
750         {
751             PRINTF("Trimming top row\n");
752             quad_count = icvTrimRow(quads,quad_count,row_min,-1);
753         }
754         else
755         {
756             PRINTF("Trimming bottom row\n");
757             quad_count = icvTrimRow(quads,quad_count,row_max,+1);
758         }
759     }
760 #endif
761 
762     // check edges of inner quads
763     // if there is an outer quad missing, fill it in
764     // first order all inner quads
765     int found = 0;
766     for (int i=0; i<quad_count; i++)
767     {
768         if (quads[i]->count == 4)
769         {   // ok, look at neighbors
770             int col = quads[i]->col;
771             int row = quads[i]->row;
772             for (int j=0; j<4; j++)
773             {
774                 switch(j)   // adjust col, row for this quad
775                 {       // start at top left, go clockwise
776                 case 0:
777                     row--; col--; break;
778                 case 1:
779                     col += 2; break;
780                 case 2:
781                     row += 2;   break;
782                 case 3:
783                     col -= 2; break;
784                 }
785                 CvCBQuad *neighbor = quads[i]->neighbors[j];
786                 if (neighbor && !neighbor->ordered && // is it an inner quad?
787                     col <= col_max && col >= col_min &&
788                     row <= row_max && row >= row_min)
789                 {
790                     // if so, set in order
791                     PRINTF("Adding inner: col: %d  row: %d\n", col, row);
792                     found++;
793                     icvOrderQuad(neighbor, quads[i]->corners[j], (j+2)%4);
794                     neighbor->ordered = true;
795                     neighbor->row = row;
796                     neighbor->col = col;
797                 }
798             }
799         }
800     }
801 
802     // if we have found inner quads, add corresponding outer quads,
803     //   which are missing
804     if (found > 0)
805     {
806         PRINTF("Found %d inner quads not connected to outer quads, repairing\n", found);
807         for (int i=0; i<quad_count; i++)
808         {
809             if (quads[i]->count < 4 && quads[i]->ordered)
810             {
811                 int added = icvAddOuterQuad(quads[i],quads,quad_count,all_quads,*all_count,corners);
812                 *all_count += added;
813                 quad_count += added;
814             }
815         }
816     }
817 
818 
819     // final trimming of outer quads
820     if (dcol == w && drow == h) // found correct inner quads
821     {
822         PRINTF("Inner bounds ok, check outer quads\n");
823         int rcount = quad_count;
824         for (int i=quad_count-1; i>=0; i--) // eliminate any quad not connected to
825             // an ordered quad
826         {
827             if (quads[i]->ordered == false)
828             {
829                 bool outer = false;
830                 for (int j=0; j<4; j++) // any neighbors that are ordered?
831                 {
832                     if (quads[i]->neighbors[j] && quads[i]->neighbors[j]->ordered)
833                         outer = true;
834                 }
835                 if (!outer) // not an outer quad, eliminate
836                 {
837                     PRINTF("Removing quad %d\n", i);
838                     icvRemoveQuadFromGroup(quads,rcount,quads[i]);
839                     rcount--;
840                 }
841             }
842 
843         }
844         return rcount;
845     }
846 
847     return 0;
848 }
849 
850 
851 // add an outer quad
852 // looks for the neighbor of <quad> that isn't present,
853 //   tries to add it in.
854 // <quad> is ordered
855 
856 static int
icvAddOuterQuad(CvCBQuad * quad,CvCBQuad ** quads,int quad_count,CvCBQuad ** all_quads,int all_count,CvCBCorner ** corners)857 icvAddOuterQuad( CvCBQuad *quad, CvCBQuad **quads, int quad_count,
858         CvCBQuad **all_quads, int all_count, CvCBCorner **corners )
859 
860 {
861     int added = 0;
862     for (int i=0; i<4; i++) // find no-neighbor corners
863     {
864         if (!quad->neighbors[i])    // ok, create and add neighbor
865         {
866             int j = (i+2)%4;
867             PRINTF("Adding quad as neighbor 2\n");
868             CvCBQuad *q = &(*all_quads)[all_count];
869             memset( q, 0, sizeof(*q) );
870             added++;
871             quads[quad_count] = q;
872             quad_count++;
873 
874             // set neighbor and group id
875             quad->neighbors[i] = q;
876             quad->count += 1;
877             q->neighbors[j] = quad;
878             q->group_idx = quad->group_idx;
879             q->count = 1;   // number of neighbors
880             q->ordered = false;
881             q->edge_len = quad->edge_len;
882 
883             // make corners of new quad
884             // same as neighbor quad, but offset
885             CvPoint2D32f pt = quad->corners[i]->pt;
886             CvCBCorner* corner;
887             float dx = pt.x - quad->corners[j]->pt.x;
888             float dy = pt.y - quad->corners[j]->pt.y;
889             for (int k=0; k<4; k++)
890             {
891                 corner = &(*corners)[all_count*4+k];
892                 pt = quad->corners[k]->pt;
893                 memset( corner, 0, sizeof(*corner) );
894                 corner->pt = pt;
895                 q->corners[k] = corner;
896                 corner->pt.x += dx;
897                 corner->pt.y += dy;
898             }
899             // have to set exact corner
900             q->corners[j] = quad->corners[i];
901 
902             // now find other neighbor and add it, if possible
903             if (quad->neighbors[(i+3)%4] &&
904                 quad->neighbors[(i+3)%4]->ordered &&
905                 quad->neighbors[(i+3)%4]->neighbors[i] &&
906                 quad->neighbors[(i+3)%4]->neighbors[i]->ordered )
907             {
908                 CvCBQuad *qn = quad->neighbors[(i+3)%4]->neighbors[i];
909                 q->count = 2;
910                 q->neighbors[(j+1)%4] = qn;
911                 qn->neighbors[(i+1)%4] = q;
912                 qn->count += 1;
913                 // have to set exact corner
914                 q->corners[(j+1)%4] = qn->corners[(i+1)%4];
915             }
916 
917             all_count++;
918         }
919     }
920     return added;
921 }
922 
923 
924 // trimming routines
925 #ifdef ENABLE_TRIM_COL_ROW
926 static int
icvTrimCol(CvCBQuad ** quads,int count,int col,int dir)927 icvTrimCol(CvCBQuad **quads, int count, int col, int dir)
928 {
929     int rcount = count;
930     // find the right quad(s)
931     for (int i=0; i<count; i++)
932     {
933 #ifdef DEBUG_CHESSBOARD
934         if (quads[i]->ordered)
935             PRINTF("index: %d  cur: %d\n", col, quads[i]->col);
936 #endif
937         if (quads[i]->ordered && quads[i]->col == col)
938         {
939             if (dir == 1)
940             {
941                 if (quads[i]->neighbors[1])
942                 {
943                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[1]);
944                     rcount--;
945                 }
946                 if (quads[i]->neighbors[2])
947                 {
948                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[2]);
949                     rcount--;
950                 }
951             }
952             else
953             {
954                 if (quads[i]->neighbors[0])
955                 {
956                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[0]);
957                     rcount--;
958                 }
959                 if (quads[i]->neighbors[3])
960                 {
961                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[3]);
962                     rcount--;
963                 }
964             }
965 
966         }
967     }
968     return rcount;
969 }
970 
971 static int
icvTrimRow(CvCBQuad ** quads,int count,int row,int dir)972 icvTrimRow(CvCBQuad **quads, int count, int row, int dir)
973 {
974     int i, rcount = count;
975     // find the right quad(s)
976     for (i=0; i<count; i++)
977     {
978 #ifdef DEBUG_CHESSBOARD
979         if (quads[i]->ordered)
980             PRINTF("index: %d  cur: %d\n", row, quads[i]->row);
981 #endif
982         if (quads[i]->ordered && quads[i]->row == row)
983         {
984             if (dir == 1)   // remove from bottom
985             {
986                 if (quads[i]->neighbors[2])
987                 {
988                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[2]);
989                     rcount--;
990                 }
991                 if (quads[i]->neighbors[3])
992                 {
993                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[3]);
994                     rcount--;
995                 }
996             }
997             else    // remove from top
998             {
999                 if (quads[i]->neighbors[0])
1000                 {
1001                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[0]);
1002                     rcount--;
1003                 }
1004                 if (quads[i]->neighbors[1])
1005                 {
1006                     icvRemoveQuadFromGroup(quads,rcount,quads[i]->neighbors[1]);
1007                     rcount--;
1008                 }
1009             }
1010 
1011         }
1012     }
1013     return rcount;
1014 }
1015 #endif
1016 
1017 //
1018 // remove quad from quad group
1019 //
1020 
1021 static void
icvRemoveQuadFromGroup(CvCBQuad ** quads,int count,CvCBQuad * q0)1022 icvRemoveQuadFromGroup(CvCBQuad **quads, int count, CvCBQuad *q0)
1023 {
1024     int i, j;
1025     // remove any references to this quad as a neighbor
1026     for(i = 0; i < count; i++ )
1027     {
1028         CvCBQuad *q = quads[i];
1029         for(j = 0; j < 4; j++ )
1030         {
1031             if( q->neighbors[j] == q0 )
1032             {
1033                 q->neighbors[j] = 0;
1034                 q->count--;
1035                 for(int k = 0; k < 4; k++ )
1036                     if( q0->neighbors[k] == q )
1037                     {
1038                         q0->neighbors[k] = 0;
1039                         q0->count--;
1040                         break;
1041                     }
1042                     break;
1043             }
1044         }
1045     }
1046 
1047     // remove the quad
1048     for(i = 0; i < count; i++ )
1049     {
1050         CvCBQuad *q = quads[i];
1051         if (q == q0)
1052         {
1053             quads[i] = quads[count-1];
1054             break;
1055         }
1056     }
1057 }
1058 
1059 //
1060 // put quad into correct order, where <corner> has value <common>
1061 //
1062 
1063 static void
icvOrderQuad(CvCBQuad * quad,CvCBCorner * corner,int common)1064 icvOrderQuad(CvCBQuad *quad, CvCBCorner *corner, int common)
1065 {
1066     // find the corner
1067     int tc;
1068     for (tc=0; tc<4; tc++)
1069         if (quad->corners[tc]->pt.x == corner->pt.x &&
1070             quad->corners[tc]->pt.y == corner->pt.y)
1071             break;
1072 
1073     // set corner order
1074     // shift
1075     while (tc != common)
1076     {
1077         // shift by one
1078         CvCBCorner *tempc;
1079         CvCBQuad *tempq;
1080         tempc = quad->corners[3];
1081         tempq = quad->neighbors[3];
1082         for (int i=3; i>0; i--)
1083         {
1084             quad->corners[i] = quad->corners[i-1];
1085             quad->neighbors[i] = quad->neighbors[i-1];
1086         }
1087         quad->corners[0] = tempc;
1088         quad->neighbors[0] = tempq;
1089         tc++;
1090         tc = tc%4;
1091     }
1092 }
1093 
1094 
1095 // if we found too many connect quads, remove those which probably do not belong.
1096 static int
icvCleanFoundConnectedQuads(int quad_count,CvCBQuad ** quad_group,CvSize pattern_size)1097 icvCleanFoundConnectedQuads( int quad_count, CvCBQuad **quad_group, CvSize pattern_size )
1098 {
1099     CvPoint2D32f center;
1100     int i, j, k;
1101     // number of quads this pattern should contain
1102     int count = ((pattern_size.width + 1)*(pattern_size.height + 1) + 1)/2;
1103 
1104     // if we have more quadrangles than we should,
1105     // try to eliminate duplicates or ones which don't belong to the pattern rectangle...
1106     if( quad_count <= count )
1107         return quad_count;
1108 
1109     // create an array of quadrangle centers
1110     cv::AutoBuffer<CvPoint2D32f> centers( quad_count );
1111     cv::Ptr<CvMemStorage> temp_storage(cvCreateMemStorage(0));
1112 
1113     for( i = 0; i < quad_count; i++ )
1114     {
1115         CvPoint2D32f ci;
1116         CvCBQuad* q = quad_group[i];
1117 
1118         for( j = 0; j < 4; j++ )
1119         {
1120             CvPoint2D32f pt = q->corners[j]->pt;
1121             ci.x += pt.x;
1122             ci.y += pt.y;
1123         }
1124 
1125         ci.x *= 0.25f;
1126         ci.y *= 0.25f;
1127 
1128         centers[i] = ci;
1129         center.x += ci.x;
1130         center.y += ci.y;
1131     }
1132     center.x /= quad_count;
1133     center.y /= quad_count;
1134 
1135     // If we still have more quadrangles than we should,
1136     // we try to eliminate bad ones based on minimizing the bounding box.
1137     // We iteratively remove the point which reduces the size of
1138     // the bounding box of the blobs the most
1139     // (since we want the rectangle to be as small as possible)
1140     // remove the quadrange that causes the biggest reduction
1141     // in pattern size until we have the correct number
1142     for( ; quad_count > count; quad_count-- )
1143     {
1144         double min_box_area = DBL_MAX;
1145         int skip, min_box_area_index = -1;
1146 
1147         // For each point, calculate box area without that point
1148         for( skip = 0; skip < quad_count; skip++ )
1149         {
1150             // get bounding rectangle
1151             CvPoint2D32f temp = centers[skip]; // temporarily make index 'skip' the same as
1152             centers[skip] = center;            // pattern center (so it is not counted for convex hull)
1153             CvMat pointMat = cvMat(1, quad_count, CV_32FC2, centers);
1154             CvSeq *hull = cvConvexHull2( &pointMat, temp_storage, CV_CLOCKWISE, 1 );
1155             centers[skip] = temp;
1156             double hull_area = fabs(cvContourArea(hull, CV_WHOLE_SEQ));
1157 
1158             // remember smallest box area
1159             if( hull_area < min_box_area )
1160             {
1161                 min_box_area = hull_area;
1162                 min_box_area_index = skip;
1163             }
1164             cvClearMemStorage( temp_storage );
1165         }
1166 
1167         CvCBQuad *q0 = quad_group[min_box_area_index];
1168 
1169         // remove any references to this quad as a neighbor
1170         for( i = 0; i < quad_count; i++ )
1171         {
1172             CvCBQuad *q = quad_group[i];
1173             for( j = 0; j < 4; j++ )
1174             {
1175                 if( q->neighbors[j] == q0 )
1176                 {
1177                     q->neighbors[j] = 0;
1178                     q->count--;
1179                     for( k = 0; k < 4; k++ )
1180                         if( q0->neighbors[k] == q )
1181                         {
1182                             q0->neighbors[k] = 0;
1183                             q0->count--;
1184                             break;
1185                         }
1186                     break;
1187                 }
1188             }
1189         }
1190 
1191         // remove the quad
1192         quad_count--;
1193         quad_group[min_box_area_index] = quad_group[quad_count];
1194         centers[min_box_area_index] = centers[quad_count];
1195     }
1196 
1197     return quad_count;
1198 }
1199 
1200 //=====================================================================================
1201 
1202 static int
icvFindConnectedQuads(CvCBQuad * quad,int quad_count,CvCBQuad ** out_group,int group_idx,CvMemStorage * storage)1203 icvFindConnectedQuads( CvCBQuad *quad, int quad_count, CvCBQuad **out_group,
1204                        int group_idx, CvMemStorage* storage )
1205 {
1206     cv::Ptr<CvMemStorage> temp_storage(cvCreateChildMemStorage( storage ));
1207     CvSeq* stack = cvCreateSeq( 0, sizeof(*stack), sizeof(void*), temp_storage );
1208     int i, count = 0;
1209 
1210     // Scan the array for a first unlabeled quad
1211     for( i = 0; i < quad_count; i++ )
1212     {
1213         if( quad[i].count > 0 && quad[i].group_idx < 0)
1214             break;
1215     }
1216 
1217     // Recursively find a group of connected quads starting from the seed quad[i]
1218     if( i < quad_count )
1219     {
1220         CvCBQuad* q = &quad[i];
1221         cvSeqPush( stack, &q );
1222         out_group[count++] = q;
1223         q->group_idx = group_idx;
1224         q->ordered = false;
1225 
1226         while( stack->total )
1227         {
1228             cvSeqPop( stack, &q );
1229             for( i = 0; i < 4; i++ )
1230             {
1231                 CvCBQuad *neighbor = q->neighbors[i];
1232                 if( neighbor && neighbor->count > 0 && neighbor->group_idx < 0 )
1233                 {
1234                     cvSeqPush( stack, &neighbor );
1235                     out_group[count++] = neighbor;
1236                     neighbor->group_idx = group_idx;
1237                     neighbor->ordered = false;
1238                 }
1239             }
1240         }
1241     }
1242 
1243     return count;
1244 }
1245 
1246 
1247 //=====================================================================================
1248 
1249 static int
icvCheckQuadGroup(CvCBQuad ** quad_group,int quad_count,CvCBCorner ** out_corners,CvSize pattern_size)1250 icvCheckQuadGroup( CvCBQuad **quad_group, int quad_count,
1251                    CvCBCorner **out_corners, CvSize pattern_size )
1252 {
1253     const int ROW1 = 1000000;
1254     const int ROW2 = 2000000;
1255     const int ROW_ = 3000000;
1256     int result = 0;
1257     int i, out_corner_count = 0, corner_count = 0;
1258     std::vector<CvCBCorner*> corners(quad_count*4);
1259 
1260     int j, k, kk;
1261     int width = 0, height = 0;
1262     int hist[5] = {0,0,0,0,0};
1263     CvCBCorner* first = 0, *first2 = 0, *right, *cur, *below, *c;
1264 
1265     // build dual graph, which vertices are internal quad corners
1266     // and two vertices are connected iff they lie on the same quad edge
1267     for( i = 0; i < quad_count; i++ )
1268     {
1269         CvCBQuad* q = quad_group[i];
1270         /*CvScalar color = q->count == 0 ? cvScalar(0,255,255) :
1271                          q->count == 1 ? cvScalar(0,0,255) :
1272                          q->count == 2 ? cvScalar(0,255,0) :
1273                          q->count == 3 ? cvScalar(255,255,0) :
1274                                          cvScalar(255,0,0);*/
1275 
1276         for( j = 0; j < 4; j++ )
1277         {
1278             //cvLine( debug_img, cvPointFrom32f(q->corners[j]->pt), cvPointFrom32f(q->corners[(j+1)&3]->pt), color, 1, CV_AA, 0 );
1279             if( q->neighbors[j] )
1280             {
1281                 CvCBCorner *a = q->corners[j], *b = q->corners[(j+1)&3];
1282                 // mark internal corners that belong to:
1283                 //   - a quad with a single neighbor - with ROW1,
1284                 //   - a quad with two neighbors     - with ROW2
1285                 // make the rest of internal corners with ROW_
1286                 int row_flag = q->count == 1 ? ROW1 : q->count == 2 ? ROW2 : ROW_;
1287 
1288                 if( a->row == 0 )
1289                 {
1290                     corners[corner_count++] = a;
1291                     a->row = row_flag;
1292                 }
1293                 else if( a->row > row_flag )
1294                     a->row = row_flag;
1295 
1296                 if( q->neighbors[(j+1)&3] )
1297                 {
1298                     if( a->count >= 4 || b->count >= 4 )
1299                         goto finalize;
1300                     for( k = 0; k < 4; k++ )
1301                     {
1302                         if( a->neighbors[k] == b )
1303                             goto finalize;
1304                         if( b->neighbors[k] == a )
1305                             goto finalize;
1306                     }
1307                     a->neighbors[a->count++] = b;
1308                     b->neighbors[b->count++] = a;
1309                 }
1310             }
1311         }
1312     }
1313 
1314     if( corner_count != pattern_size.width*pattern_size.height )
1315         goto finalize;
1316 
1317     for( i = 0; i < corner_count; i++ )
1318     {
1319         int n = corners[i]->count;
1320         assert( 0 <= n && n <= 4 );
1321         hist[n]++;
1322         if( !first && n == 2 )
1323         {
1324             if( corners[i]->row == ROW1 )
1325                 first = corners[i];
1326             else if( !first2 && corners[i]->row == ROW2 )
1327                 first2 = corners[i];
1328         }
1329     }
1330 
1331     // start with a corner that belongs to a quad with a signle neighbor.
1332     // if we do not have such, start with a corner of a quad with two neighbors.
1333     if( !first )
1334         first = first2;
1335 
1336     if( !first || hist[0] != 0 || hist[1] != 0 || hist[2] != 4 ||
1337         hist[3] != (pattern_size.width + pattern_size.height)*2 - 8 )
1338         goto finalize;
1339 
1340     cur = first;
1341     right = below = 0;
1342     out_corners[out_corner_count++] = cur;
1343 
1344     for( k = 0; k < 4; k++ )
1345     {
1346         c = cur->neighbors[k];
1347         if( c )
1348         {
1349             if( !right )
1350                 right = c;
1351             else if( !below )
1352                 below = c;
1353         }
1354     }
1355 
1356     if( !right || (right->count != 2 && right->count != 3) ||
1357         !below || (below->count != 2 && below->count != 3) )
1358         goto finalize;
1359 
1360     cur->row = 0;
1361     //cvCircle( debug_img, cvPointFrom32f(cur->pt), 3, cvScalar(0,255,0), -1, 8, 0 );
1362 
1363     first = below; // remember the first corner in the next row
1364     // find and store the first row (or column)
1365     for(j=1;;j++)
1366     {
1367         right->row = 0;
1368         out_corners[out_corner_count++] = right;
1369         //cvCircle( debug_img, cvPointFrom32f(right->pt), 3, cvScalar(0,255-j*10,0), -1, 8, 0 );
1370         if( right->count == 2 )
1371             break;
1372         if( right->count != 3 || out_corner_count >= MAX(pattern_size.width,pattern_size.height) )
1373             goto finalize;
1374         cur = right;
1375         for( k = 0; k < 4; k++ )
1376         {
1377             c = cur->neighbors[k];
1378             if( c && c->row > 0 )
1379             {
1380                 for( kk = 0; kk < 4; kk++ )
1381                 {
1382                     if( c->neighbors[kk] == below )
1383                         break;
1384                 }
1385                 if( kk < 4 )
1386                     below = c;
1387                 else
1388                     right = c;
1389             }
1390         }
1391     }
1392 
1393     width = out_corner_count;
1394     if( width == pattern_size.width )
1395         height = pattern_size.height;
1396     else if( width == pattern_size.height )
1397         height = pattern_size.width;
1398     else
1399         goto finalize;
1400 
1401     // find and store all the other rows
1402     for( i = 1; ; i++ )
1403     {
1404         if( !first )
1405             break;
1406         cur = first;
1407         first = 0;
1408         for( j = 0;; j++ )
1409         {
1410             cur->row = i;
1411             out_corners[out_corner_count++] = cur;
1412             //cvCircle( debug_img, cvPointFrom32f(cur->pt), 3, cvScalar(0,0,255-j*10), -1, 8, 0 );
1413             if( cur->count == 2 + (i < height-1) && j > 0 )
1414                 break;
1415 
1416             right = 0;
1417 
1418             // find a neighbor that has not been processed yet
1419             // and that has a neighbor from the previous row
1420             for( k = 0; k < 4; k++ )
1421             {
1422                 c = cur->neighbors[k];
1423                 if( c && c->row > i )
1424                 {
1425                     for( kk = 0; kk < 4; kk++ )
1426                     {
1427                         if( c->neighbors[kk] && c->neighbors[kk]->row == i-1 )
1428                             break;
1429                     }
1430                     if( kk < 4 )
1431                     {
1432                         right = c;
1433                         if( j > 0 )
1434                             break;
1435                     }
1436                     else if( j == 0 )
1437                         first = c;
1438                 }
1439             }
1440             if( !right )
1441                 goto finalize;
1442             cur = right;
1443         }
1444 
1445         if( j != width - 1 )
1446             goto finalize;
1447     }
1448 
1449     if( out_corner_count != corner_count )
1450         goto finalize;
1451 
1452     // check if we need to transpose the board
1453     if( width != pattern_size.width )
1454     {
1455         CV_SWAP( width, height, k );
1456 
1457         memcpy( &corners[0], out_corners, corner_count*sizeof(corners[0]) );
1458         for( i = 0; i < height; i++ )
1459             for( j = 0; j < width; j++ )
1460                 out_corners[i*width + j] = corners[j*height + i];
1461     }
1462 
1463     // check if we need to revert the order in each row
1464     {
1465         CvPoint2D32f p0 = out_corners[0]->pt, p1 = out_corners[pattern_size.width-1]->pt,
1466                      p2 = out_corners[pattern_size.width]->pt;
1467         if( (p1.x - p0.x)*(p2.y - p1.y) - (p1.y - p0.y)*(p2.x - p1.x) < 0 )
1468         {
1469             if( width % 2 == 0 )
1470             {
1471                 for( i = 0; i < height; i++ )
1472                     for( j = 0; j < width/2; j++ )
1473                         CV_SWAP( out_corners[i*width+j], out_corners[i*width+width-j-1], c );
1474             }
1475             else
1476             {
1477                 for( j = 0; j < width; j++ )
1478                     for( i = 0; i < height/2; i++ )
1479                         CV_SWAP( out_corners[i*width+j], out_corners[(height - i - 1)*width+j], c );
1480             }
1481         }
1482     }
1483 
1484     result = corner_count;
1485 
1486 finalize:
1487 
1488     if( result <= 0 )
1489     {
1490         corner_count = MIN( corner_count, pattern_size.width*pattern_size.height );
1491         for( i = 0; i < corner_count; i++ )
1492             out_corners[i] = corners[i];
1493         result = -corner_count;
1494 
1495         if (result == -pattern_size.width*pattern_size.height)
1496             result = -result;
1497     }
1498 
1499     return result;
1500 }
1501 
1502 
1503 
1504 
1505 //=====================================================================================
1506 
icvFindQuadNeighbors(CvCBQuad * quads,int quad_count)1507 static void icvFindQuadNeighbors( CvCBQuad *quads, int quad_count )
1508 {
1509     const float thresh_scale = 1.f;
1510     int idx, i, k, j;
1511     float dx, dy, dist;
1512 
1513     // find quad neighbors
1514     for( idx = 0; idx < quad_count; idx++ )
1515     {
1516         CvCBQuad* cur_quad = &quads[idx];
1517 
1518         // choose the points of the current quadrangle that are close to
1519         // some points of the other quadrangles
1520         // (it can happen for split corners (due to dilation) of the
1521         // checker board). Search only in other quadrangles!
1522 
1523         // for each corner of this quadrangle
1524         for( i = 0; i < 4; i++ )
1525         {
1526             CvPoint2D32f pt;
1527             float min_dist = FLT_MAX;
1528             int closest_corner_idx = -1;
1529             CvCBQuad *closest_quad = 0;
1530             CvCBCorner *closest_corner = 0;
1531 
1532             if( cur_quad->neighbors[i] )
1533                 continue;
1534 
1535             pt = cur_quad->corners[i]->pt;
1536 
1537             // find the closest corner in all other quadrangles
1538             for( k = 0; k < quad_count; k++ )
1539             {
1540                 if( k == idx )
1541                     continue;
1542 
1543                 for( j = 0; j < 4; j++ )
1544                 {
1545                     if( quads[k].neighbors[j] )
1546                         continue;
1547 
1548                     dx = pt.x - quads[k].corners[j]->pt.x;
1549                     dy = pt.y - quads[k].corners[j]->pt.y;
1550                     dist = dx * dx + dy * dy;
1551 
1552                     if( dist < min_dist &&
1553                         dist <= cur_quad->edge_len*thresh_scale &&
1554                         dist <= quads[k].edge_len*thresh_scale )
1555                     {
1556                         // check edge lengths, make sure they're compatible
1557                         // edges that are different by more than 1:4 are rejected
1558                         float ediff = cur_quad->edge_len - quads[k].edge_len;
1559                         if (ediff > 32*cur_quad->edge_len ||
1560                             ediff > 32*quads[k].edge_len)
1561                         {
1562                             PRINTF("Incompatible edge lengths\n");
1563                             continue;
1564                         }
1565                         closest_corner_idx = j;
1566                         closest_quad = &quads[k];
1567                         min_dist = dist;
1568                     }
1569                 }
1570             }
1571 
1572             // we found a matching corner point?
1573             if( closest_corner_idx >= 0 && min_dist < FLT_MAX )
1574             {
1575                 // If another point from our current quad is closer to the found corner
1576                 // than the current one, then we don't count this one after all.
1577                 // This is necessary to support small squares where otherwise the wrong
1578                 // corner will get matched to closest_quad;
1579                 closest_corner = closest_quad->corners[closest_corner_idx];
1580 
1581                 for( j = 0; j < 4; j++ )
1582                 {
1583                     if( cur_quad->neighbors[j] == closest_quad )
1584                         break;
1585 
1586                     dx = closest_corner->pt.x - cur_quad->corners[j]->pt.x;
1587                     dy = closest_corner->pt.y - cur_quad->corners[j]->pt.y;
1588 
1589                     if( dx * dx + dy * dy < min_dist )
1590                         break;
1591                 }
1592 
1593                 if( j < 4 || cur_quad->count >= 4 || closest_quad->count >= 4 )
1594                     continue;
1595 
1596                 // Check that each corner is a neighbor of different quads
1597                 for( j = 0; j < closest_quad->count; j++ )
1598                 {
1599                     if( closest_quad->neighbors[j] == cur_quad )
1600                         break;
1601                 }
1602                 if( j < closest_quad->count )
1603                     continue;
1604 
1605                 // check whether the closest corner to closest_corner
1606                 // is different from cur_quad->corners[i]->pt
1607                 for( k = 0; k < quad_count; k++ )
1608                 {
1609                     CvCBQuad* q = &quads[k];
1610                     if( k == idx || q == closest_quad )
1611                         continue;
1612 
1613                     for( j = 0; j < 4; j++ )
1614                         if( !q->neighbors[j] )
1615                         {
1616                             dx = closest_corner->pt.x - q->corners[j]->pt.x;
1617                             dy = closest_corner->pt.y - q->corners[j]->pt.y;
1618                             dist = dx*dx + dy*dy;
1619                             if( dist < min_dist )
1620                                 break;
1621                         }
1622                     if( j < 4 )
1623                         break;
1624                 }
1625 
1626                 if( k < quad_count )
1627                     continue;
1628 
1629                 closest_corner->pt.x = (pt.x + closest_corner->pt.x) * 0.5f;
1630                 closest_corner->pt.y = (pt.y + closest_corner->pt.y) * 0.5f;
1631 
1632                 // We've found one more corner - remember it
1633                 cur_quad->count++;
1634                 cur_quad->neighbors[i] = closest_quad;
1635                 cur_quad->corners[i] = closest_corner;
1636 
1637                 closest_quad->count++;
1638                 closest_quad->neighbors[closest_corner_idx] = cur_quad;
1639             }
1640         }
1641     }
1642 }
1643 
1644 //=====================================================================================
1645 
1646 // returns corners in clockwise order
1647 // corners don't necessarily start at same position on quad (e.g.,
1648 //   top left corner)
1649 
1650 static int
icvGenerateQuads(CvCBQuad ** out_quads,CvCBCorner ** out_corners,CvMemStorage * storage,CvMat * image,int flags)1651 icvGenerateQuads( CvCBQuad **out_quads, CvCBCorner **out_corners,
1652                   CvMemStorage *storage, CvMat *image, int flags )
1653 {
1654     int quad_count = 0;
1655     cv::Ptr<CvMemStorage> temp_storage;
1656 
1657     if( out_quads )
1658         *out_quads = 0;
1659 
1660     if( out_corners )
1661         *out_corners = 0;
1662 
1663     CvSeq *src_contour = 0;
1664     CvSeq *root;
1665     CvContourEx* board = 0;
1666     CvContourScanner scanner;
1667     int i, idx, min_size;
1668 
1669     CV_Assert( out_corners && out_quads );
1670 
1671     // empiric bound for minimal allowed perimeter for squares
1672     min_size = 25; //cvRound( image->cols * image->rows * .03 * 0.01 * 0.92 );
1673 
1674     // create temporary storage for contours and the sequence of pointers to found quadrangles
1675     temp_storage.reset(cvCreateChildMemStorage( storage ));
1676     root = cvCreateSeq( 0, sizeof(CvSeq), sizeof(CvSeq*), temp_storage );
1677 
1678     // initialize contour retrieving routine
1679     scanner = cvStartFindContours( image, temp_storage, sizeof(CvContourEx),
1680                                    CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE );
1681 
1682     // get all the contours one by one
1683     while( (src_contour = cvFindNextContour( scanner )) != 0 )
1684     {
1685         CvSeq *dst_contour = 0;
1686         CvRect rect = ((CvContour*)src_contour)->rect;
1687 
1688         // reject contours with too small perimeter
1689         if( CV_IS_SEQ_HOLE(src_contour) && rect.width*rect.height >= min_size )
1690         {
1691             const int min_approx_level = 1, max_approx_level = MAX_CONTOUR_APPROX;
1692             int approx_level;
1693             for( approx_level = min_approx_level; approx_level <= max_approx_level; approx_level++ )
1694             {
1695                 dst_contour = cvApproxPoly( src_contour, sizeof(CvContour), temp_storage,
1696                                             CV_POLY_APPROX_DP, (float)approx_level );
1697                 if( dst_contour->total == 4 )
1698                     break;
1699 
1700                 // we call this again on its own output, because sometimes
1701                 // cvApproxPoly() does not simplify as much as it should.
1702                 dst_contour = cvApproxPoly( dst_contour, sizeof(CvContour), temp_storage,
1703                                             CV_POLY_APPROX_DP, (float)approx_level );
1704 
1705                 if( dst_contour->total == 4 )
1706                     break;
1707             }
1708 
1709             // reject non-quadrangles
1710             if( dst_contour->total == 4 && cvCheckContourConvexity(dst_contour) )
1711             {
1712                 CvPoint pt[4];
1713                 double d1, d2, p = cvContourPerimeter(dst_contour);
1714                 double area = fabs(cvContourArea(dst_contour, CV_WHOLE_SEQ));
1715                 double dx, dy;
1716 
1717                 for( i = 0; i < 4; i++ )
1718                     pt[i] = *(CvPoint*)cvGetSeqElem(dst_contour, i);
1719 
1720                 dx = pt[0].x - pt[2].x;
1721                 dy = pt[0].y - pt[2].y;
1722                 d1 = sqrt(dx*dx + dy*dy);
1723 
1724                 dx = pt[1].x - pt[3].x;
1725                 dy = pt[1].y - pt[3].y;
1726                 d2 = sqrt(dx*dx + dy*dy);
1727 
1728                 // philipg.  Only accept those quadrangles which are more square
1729                 // than rectangular and which are big enough
1730                 double d3, d4;
1731                 dx = pt[0].x - pt[1].x;
1732                 dy = pt[0].y - pt[1].y;
1733                 d3 = sqrt(dx*dx + dy*dy);
1734                 dx = pt[1].x - pt[2].x;
1735                 dy = pt[1].y - pt[2].y;
1736                 d4 = sqrt(dx*dx + dy*dy);
1737                 if( !(flags & CV_CALIB_CB_FILTER_QUADS) ||
1738                     (d3*4 > d4 && d4*4 > d3 && d3*d4 < area*1.5 && area > min_size &&
1739                     d1 >= 0.15 * p && d2 >= 0.15 * p) )
1740                 {
1741                     CvContourEx* parent = (CvContourEx*)(src_contour->v_prev);
1742                     parent->counter++;
1743                     if( !board || board->counter < parent->counter )
1744                         board = parent;
1745                     dst_contour->v_prev = (CvSeq*)parent;
1746                     //for( i = 0; i < 4; i++ ) cvLine( debug_img, pt[i], pt[(i+1)&3], cvScalar(200,255,255), 1, CV_AA, 0 );
1747                     cvSeqPush( root, &dst_contour );
1748                 }
1749             }
1750         }
1751     }
1752 
1753     // finish contour retrieving
1754     cvEndFindContours( &scanner );
1755 
1756     // allocate quad & corner buffers
1757     *out_quads = (CvCBQuad*)cvAlloc((root->total+root->total / 2) * sizeof((*out_quads)[0]));
1758     *out_corners = (CvCBCorner*)cvAlloc((root->total+root->total / 2) * 4 * sizeof((*out_corners)[0]));
1759 
1760     // Create array of quads structures
1761     for( idx = 0; idx < root->total; idx++ )
1762     {
1763         CvCBQuad* q = &(*out_quads)[quad_count];
1764         src_contour = *(CvSeq**)cvGetSeqElem( root, idx );
1765         if( (flags & CV_CALIB_CB_FILTER_QUADS) && src_contour->v_prev != (CvSeq*)board )
1766             continue;
1767 
1768         // reset group ID
1769         memset( q, 0, sizeof(*q) );
1770         q->group_idx = -1;
1771         assert( src_contour->total == 4 );
1772         for( i = 0; i < 4; i++ )
1773         {
1774             CvPoint2D32f pt = cvPointTo32f(*(CvPoint*)cvGetSeqElem(src_contour, i));
1775             CvCBCorner* corner = &(*out_corners)[quad_count*4 + i];
1776 
1777             memset( corner, 0, sizeof(*corner) );
1778             corner->pt = pt;
1779             q->corners[i] = corner;
1780         }
1781         q->edge_len = FLT_MAX;
1782         for( i = 0; i < 4; i++ )
1783         {
1784             float dx = q->corners[i]->pt.x - q->corners[(i+1)&3]->pt.x;
1785             float dy = q->corners[i]->pt.y - q->corners[(i+1)&3]->pt.y;
1786             float d = dx*dx + dy*dy;
1787             if( q->edge_len > d )
1788                 q->edge_len = d;
1789         }
1790         quad_count++;
1791     }
1792 
1793     return quad_count;
1794 }
1795 
1796 
1797 CV_IMPL void
cvDrawChessboardCorners(CvArr * _image,CvSize pattern_size,CvPoint2D32f * corners,int count,int found)1798 cvDrawChessboardCorners( CvArr* _image, CvSize pattern_size,
1799                          CvPoint2D32f* corners, int count, int found )
1800 {
1801     const int shift = 0;
1802     const int radius = 4;
1803     const int r = radius*(1 << shift);
1804     int i;
1805     CvMat stub, *image;
1806     double scale = 1;
1807     int type, cn, line_type;
1808 
1809     image = cvGetMat( _image, &stub );
1810 
1811     type = CV_MAT_TYPE(image->type);
1812     cn = CV_MAT_CN(type);
1813     if( cn != 1 && cn != 3 && cn != 4 )
1814         CV_Error( CV_StsUnsupportedFormat, "Number of channels must be 1, 3 or 4" );
1815 
1816     switch( CV_MAT_DEPTH(image->type) )
1817     {
1818     case CV_8U:
1819         scale = 1;
1820         break;
1821     case CV_16U:
1822         scale = 256;
1823         break;
1824     case CV_32F:
1825         scale = 1./255;
1826         break;
1827     default:
1828         CV_Error( CV_StsUnsupportedFormat,
1829             "Only 8-bit, 16-bit or floating-point 32-bit images are supported" );
1830     }
1831 
1832     line_type = type == CV_8UC1 || type == CV_8UC3 ? CV_AA : 8;
1833 
1834     if( !found )
1835     {
1836         CvScalar color(0,0,255,0);
1837         if( cn == 1 )
1838             color = cvScalarAll(200);
1839         color.val[0] *= scale;
1840         color.val[1] *= scale;
1841         color.val[2] *= scale;
1842         color.val[3] *= scale;
1843 
1844         for( i = 0; i < count; i++ )
1845         {
1846             CvPoint pt;
1847             pt.x = cvRound(corners[i].x*(1 << shift));
1848             pt.y = cvRound(corners[i].y*(1 << shift));
1849             cvLine( image, cvPoint( pt.x - r, pt.y - r ),
1850                     cvPoint( pt.x + r, pt.y + r ), color, 1, line_type, shift );
1851             cvLine( image, cvPoint( pt.x - r, pt.y + r),
1852                     cvPoint( pt.x + r, pt.y - r), color, 1, line_type, shift );
1853             cvCircle( image, pt, r+(1<<shift), color, 1, line_type, shift );
1854         }
1855     }
1856     else
1857     {
1858         int x, y;
1859         CvPoint prev_pt;
1860         const int line_max = 7;
1861         static const CvScalar line_colors[line_max] =
1862         {
1863             CvScalar(0,0,255),
1864             CvScalar(0,128,255),
1865             CvScalar(0,200,200),
1866             CvScalar(0,255,0),
1867             CvScalar(200,200,0),
1868             CvScalar(255,0,0),
1869             CvScalar(255,0,255)
1870         };
1871 
1872         for( y = 0, i = 0; y < pattern_size.height; y++ )
1873         {
1874             CvScalar color = line_colors[y % line_max];
1875             if( cn == 1 )
1876                 color = cvScalarAll(200);
1877             color.val[0] *= scale;
1878             color.val[1] *= scale;
1879             color.val[2] *= scale;
1880             color.val[3] *= scale;
1881 
1882             for( x = 0; x < pattern_size.width; x++, i++ )
1883             {
1884                 CvPoint pt;
1885                 pt.x = cvRound(corners[i].x*(1 << shift));
1886                 pt.y = cvRound(corners[i].y*(1 << shift));
1887 
1888                 if( i != 0 )
1889                     cvLine( image, prev_pt, pt, color, 1, line_type, shift );
1890 
1891                 cvLine( image, cvPoint(pt.x - r, pt.y - r),
1892                         cvPoint(pt.x + r, pt.y + r), color, 1, line_type, shift );
1893                 cvLine( image, cvPoint(pt.x - r, pt.y + r),
1894                         cvPoint(pt.x + r, pt.y - r), color, 1, line_type, shift );
1895                 cvCircle( image, pt, r+(1<<shift), color, 1, line_type, shift );
1896                 prev_pt = pt;
1897             }
1898         }
1899     }
1900 }
1901 
findChessboardCorners(InputArray _image,Size patternSize,OutputArray corners,int flags)1902 bool cv::findChessboardCorners( InputArray _image, Size patternSize,
1903                             OutputArray corners, int flags )
1904 {
1905     int count = patternSize.area()*2;
1906     std::vector<Point2f> tmpcorners(count+1);
1907     Mat image = _image.getMat(); CvMat c_image = image;
1908     bool ok = cvFindChessboardCorners(&c_image, patternSize,
1909         (CvPoint2D32f*)&tmpcorners[0], &count, flags ) > 0;
1910     if( count > 0 )
1911     {
1912         tmpcorners.resize(count);
1913         Mat(tmpcorners).copyTo(corners);
1914     }
1915     else
1916         corners.release();
1917     return ok;
1918 }
1919 
1920 namespace
1921 {
quiet_error(int,const char *,const char *,const char *,int,void *)1922 int quiet_error(int /*status*/, const char* /*func_name*/,
1923                                        const char* /*err_msg*/, const char* /*file_name*/,
1924                                        int /*line*/, void* /*userdata*/ )
1925 {
1926   return 0;
1927 }
1928 }
1929 
drawChessboardCorners(InputOutputArray _image,Size patternSize,InputArray _corners,bool patternWasFound)1930 void cv::drawChessboardCorners( InputOutputArray _image, Size patternSize,
1931                             InputArray _corners,
1932                             bool patternWasFound )
1933 {
1934     Mat corners = _corners.getMat();
1935     if( corners.empty() )
1936         return;
1937     Mat image = _image.getMat(); CvMat c_image = _image.getMat();
1938     int nelems = corners.checkVector(2, CV_32F, true);
1939     CV_Assert(nelems >= 0);
1940     cvDrawChessboardCorners( &c_image, patternSize, corners.ptr<CvPoint2D32f>(),
1941                              nelems, patternWasFound );
1942 }
1943 
findCirclesGrid(InputArray _image,Size patternSize,OutputArray _centers,int flags,const Ptr<FeatureDetector> & blobDetector)1944 bool cv::findCirclesGrid( InputArray _image, Size patternSize,
1945                           OutputArray _centers, int flags, const Ptr<FeatureDetector> &blobDetector )
1946 {
1947     bool isAsymmetricGrid = (flags & CALIB_CB_ASYMMETRIC_GRID) ? true : false;
1948     bool isSymmetricGrid  = (flags & CALIB_CB_SYMMETRIC_GRID ) ? true : false;
1949     CV_Assert(isAsymmetricGrid ^ isSymmetricGrid);
1950 
1951     Mat image = _image.getMat();
1952     std::vector<Point2f> centers;
1953 
1954     std::vector<KeyPoint> keypoints;
1955     blobDetector->detect(image, keypoints);
1956     std::vector<Point2f> points;
1957     for (size_t i = 0; i < keypoints.size(); i++)
1958     {
1959       points.push_back (keypoints[i].pt);
1960     }
1961 
1962     if(flags & CALIB_CB_CLUSTERING)
1963     {
1964       CirclesGridClusterFinder circlesGridClusterFinder(isAsymmetricGrid);
1965       circlesGridClusterFinder.findGrid(points, patternSize, centers);
1966       Mat(centers).copyTo(_centers);
1967       return !centers.empty();
1968     }
1969 
1970     CirclesGridFinderParameters parameters;
1971     parameters.vertexPenalty = -0.6f;
1972     parameters.vertexGain = 1;
1973     parameters.existingVertexGain = 10000;
1974     parameters.edgeGain = 1;
1975     parameters.edgePenalty = -0.6f;
1976 
1977     if(flags & CALIB_CB_ASYMMETRIC_GRID)
1978       parameters.gridType = CirclesGridFinderParameters::ASYMMETRIC_GRID;
1979     if(flags & CALIB_CB_SYMMETRIC_GRID)
1980       parameters.gridType = CirclesGridFinderParameters::SYMMETRIC_GRID;
1981 
1982     const int attempts = 2;
1983     const size_t minHomographyPoints = 4;
1984     Mat H;
1985     for (int i = 0; i < attempts; i++)
1986     {
1987       centers.clear();
1988       CirclesGridFinder boxFinder(patternSize, points, parameters);
1989       bool isFound = false;
1990 #define BE_QUIET 1
1991 #if BE_QUIET
1992       void* oldCbkData;
1993       ErrorCallback oldCbk = redirectError(quiet_error, 0, &oldCbkData);
1994 #endif
1995       try
1996       {
1997         isFound = boxFinder.findHoles();
1998       }
1999       catch (const cv::Exception &)
2000       {
2001 
2002       }
2003 #if BE_QUIET
2004       redirectError(oldCbk, oldCbkData);
2005 #endif
2006       if (isFound)
2007       {
2008         switch(parameters.gridType)
2009         {
2010           case CirclesGridFinderParameters::SYMMETRIC_GRID:
2011             boxFinder.getHoles(centers);
2012             break;
2013           case CirclesGridFinderParameters::ASYMMETRIC_GRID:
2014         boxFinder.getAsymmetricHoles(centers);
2015         break;
2016           default:
2017             CV_Error(CV_StsBadArg, "Unkown pattern type");
2018         }
2019 
2020         if (i != 0)
2021         {
2022           Mat orgPointsMat;
2023           transform(centers, orgPointsMat, H.inv());
2024           convertPointsFromHomogeneous(orgPointsMat, centers);
2025         }
2026         Mat(centers).copyTo(_centers);
2027         return true;
2028       }
2029 
2030       boxFinder.getHoles(centers);
2031       if (i != attempts - 1)
2032       {
2033         if (centers.size() < minHomographyPoints)
2034           break;
2035         H = CirclesGridFinder::rectifyGrid(boxFinder.getDetectedGridSize(), centers, points, points);
2036       }
2037     }
2038     Mat(centers).copyTo(_centers);
2039     return false;
2040 }
2041 
2042 /* End of file. */
2043