cvFindCornerSubPix利用cvGoodFeaturesToTrack檢測出來的角點的基礎上，能夠將角點位置精確到亞像素級精度。
cvGoodFeaturesToTrack的使用可以參考這裏。
//cvFindCornersSubPix_demo.cpp
//http://blog.csdn.net/moc062066
//2011.07.26
#include <stdio.h>
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#pragma comment(lib, "opencv_core220d.lib")
#pragma comment(lib, "opencv_highgui220d.lib")
#pragma comment(lib, "opencv_imgproc220d.lib")
int main(int argc, char** argv)
{
FILE* fp = fopen("d:\\result.txt","w+" ) ;
const char* filename = "D:\\mochen_WIN32\\opencv\\CH10\\one_way_train_0001.jpg" ;
//const char* windowname = "http://blog.csdn.net/moc062066" ;
//img AND img_copy is the same,use to draw different result
IplImage* img = cvLoadImage(filename,CV_LOAD_IMAGE_COLOR );
IplImage* img_copy = cvCloneImage( img ) ;//a copy of img
IplImage* img_gray = cvCreateImage(cvGetSize( img ),IPL_DEPTH_8U, 1) ;
IplImage* eig_image = cvCreateImage(cvGetSize( img ),IPL_DEPTH_32F, 1);
IplImage* temp_image = cvCloneImage( eig_image ) ;
cvCvtColor(img,img_gray,CV_BGR2GRAY);
const int MAX_CORNERS = 1000 ;
CvPoint2D32f* corners = new CvPoint2D32f[ MAX_CORNERS ];
int corner_count = MAX_CORNERS;
double quality_level = 0.1; //OR 0.01
double min_distance = 5;
cvGoodFeaturesToTrack(
img_gray,
eig_image,
temp_image,
corners,
&corner_count,
quality_level,
min_distance
);
//draw corners from cvGoodFeaturesToTrack on "img"
for (int i = 0 ; i < corner_count ; ++i){
cvLine(
img,
cvPoint(corners[i].x,corners[i].y) ,
cvPoint(corners[i].x,corners[i].y),
CV_RGB(255,0,0),
5
);
fprintf(fp,"\t%f\t%f\n",corners[i].x,corners[i].y) ;
}
fprintf(fp,"\n\n\n\n\n") ;
int half_win_size = 3;//the window size will be 3+1+3=7
int iteration = 20;
double epislon = 0.1;
cvFindCornerSubPix(
img_gray,
corners,
corner_count,
cvSize(half_win_size,half_win_size),
cvSize(-1,-1),//no ignoring the neighbours of the center corner
cvTermCriteria(CV_TERMCRIT_ITER|CV_TERMCRIT_EPS,iteration,epislon)
);
//draw subpix corners on "img_copy"
for (int i=0;i<corner_count;i++){
cvLine(
img_copy,
cvPoint(corners[i].x,corners[i].y) ,
cvPoint(corners[i].x,corners[i].y),
CV_RGB(255,0,0),
5
);
fprintf(fp,"\t%f\t%f\n",corners[i].x,corners[i].y) ;
}
cvNamedWindow("cvFindCornerSubPix", CV_WINDOW_AUTOSIZE );
cvShowImage( "cvFindCornerSubPix", img );
cvNamedWindow("cvGoodFeaturesToTrack", CV_WINDOW_AUTOSIZE );
cvShowImage( "cvGoodFeaturesToTrack", img_copy );
cvWaitKey(0);
cvReleaseImage(&img_gray);
cvReleaseImage(&img);
cvReleaseImage(&img_copy);
cvDestroyWindow("cvGoodFeaturesToTrack");
cvDestroyWindow("cvFindCornerSubPix");
return 0;
}
結果：
還可以看看具體的位置差別：
226 177 223.979004 177.954727
246 457 246.342575 458.441925
206 217 205.988937 217.017212
63 233 61.92979 231.779572
59 239 57.358231 237.760956
476 127 476.999207 126.51577
244 230 244.378113 231.000763
329 261 328.071289 261.544617
41 253 39.679108 251.516586
449 206 450.561768 205.385559
298 116 297.48111 115.146233
57 249 58.309151 250.528427
65 259 63.784649 257.482605
56 233 57.358143 231.902939
480 265 481.90155 264.144104
40 266 39.356575 265.407654
282 151 280.037598 152.058228
37 247 37.105995 245.344711
391 103 393.433319 101.992729
242 141 242.607422 141.100433
186 258 187.336563 257.453247
374 279 373.053436 277.157898
55 259 53.271538 257.877075
69 242 69.2658 244.048813
260 67 259.071808 67.505707
50 252 49.351063 250.887909
356 323 355.215271 323.20282
37 260 37.986225 258.311005
336 127 337.292725 126.324081
320 163 320.452179 163.841644
305 203 303.238556 204.069641
51 267 49.322056 265.451752
46 246 44.387882 244.464386
423 150 421.249329 150.734589
64 245 62.19445 243.746231
50 239 48.513313 238.295792
365 60 366.504028 59.652817
189 209 187.248123 209.612976
60 266 59.270794 265.092224
262 191 262.622223 190.768219
288 5 287.563843 4.65015
70 252 69.444695 249.886948
421 293 419.476837 293.755798
389 233 389.720612 233.096863
510 178 508.495789 178.653564
513 327 513.642883 326.605164
285 246 285.041473 245.707077
42 243 44.218742 244.554565
74 271 74.592758 271.931274
265 290 266.595428 289.260986
45 259 43.965206 258.221985
445 81 446.234833 80.587486
262 105 260.089722 105.417213
38 238 39.463673 239.081985
179 477 178.42366 478.361267
294 349 292.825348 349.096405
291 43 291.821869 42.637604
277 72 277.381744 72.414444
466 309 466.518738 310.26712
310 306 309.965088 305.939087
361 178 362.592712 177.057404
69 265 68.396118 264.394745
65 271 64.174408 272.556793
226 274 225.409454 272.912567
346 219 345.795349 218.329971
464 163 464.552094 164.572495
70 237 70.615662 236.817734
74 298 74.548515 296.672241
402 340 402.264862 340.515778
435 247 435.498627 248.511307
68 306 68.562714 305.116577
528 279 528.224304 279.99704
60 256 58.378197 257.673218
451 357 449.710205 357.786896
226 134 224.146622 134.863815
406 190 406.038696 190.735214
312 82 313.823181 81.432472
337 366 337.767242 366.91449
432 402 432.503906 403.237396
34 235 35.783943 233.398193
72 333 72 333
63 227 62.944881 225.204498
72 303 72.011215 304.445038
497 373 497.65799 374.472382
210 313 208.663559 313.423889
387 385 385.418671 385.524963
39 272 39 272
68 300 68 300
573 294 573.499817 295.692657
68 319 69.112984 318.079987
72 312 72.112968 310.587891
170 295 170.060715 296.296753
378 137 378.369995 137.953888
61 335 60.104778 334.017151
40 228 40.901752 226.912415
66 311 66.144821 311.928802
434 112 434.703094 113.567688
353 92 352.966858 91.11277
53 327 53.927685 328.156189
56 227 57.43726 225.764465
72 323 74.141632 323.789276
277 424 277 424
58 307 57.944839 307.864197
58 329 58.423988 327.466278
294 458 295.407806 459.466583
50 259 49.397194 258.418549
60 302 60 302
47 234 47.988354 232.771988
330 52 329.634888 50.872742
48 227 50.580132 226.629684
293 429 291.427155 427.723633
61 319 60.054024 320.291595
279 6 279.202332 4.682604
55 264 54.053097 265.40564
55 243 53.70647 243.994568
152 288 151.368958 288.24527
70 338 68.620132 339.708984
561 154 562.112 153.836777
298 467 296.016693 465.889954
129 144 130.049789 143.166763
542 237 541.159363 235.351898
248 329 248.618698 330.610992
559 343 559.828735 342.710571
169 252 168.375534 250.124008
494 221 495.947693 220.213699
528 105 528.884766 104.912086
73 318 73.327011 317.454468
145 477 145 477
48 272 49.243771 273.165466
58 343 59.737438 341.331635
552 192 552.329285 193.175949
587 250 585.283508 251.023361
521 139 519.62085 139.533493
188 376 188 376
161 477 160.223663 478.555725
286 438 287.129913 439.437408
528 435 528.64801 436.565552
53 304 53 304
64 327 64.307709 326.131226
206 173 205.530167 172.02626
53 321 52.927059 322.150146
290 453 289.464203 451.641998
283 425 284.591217 425.801331
59 272 59.303421 272.722107
2 195 0.55171 194.967331
594 209 595.181274 208.285736
50 309 50.056606 310.088776
594 301 594.44751 302.387329
110 465 112.678375 464.216278
105 301 105.904839 299.43158
58 313 59.005356 313.973969
580 351 581.15625 350.483337
65 347 64.425552 348.0896
284 368 285.773041 367.813232
242 102 241.573944 100.385773
543 391 544.625549 390.523132
54 272 53.65321 272.630188
120 477 120 477
65 339 63.423409 340.927551
489 94 488.384949 92.754433
65 332 63.918072 333.602203
26 266 25.558767 264.518463
291 401 289.508911 400.552765
141 433 141 433
161 434 161.566635 432.378479
143 427 144.209717 424.16922
144 453 146.34552 450.987305
50 315 49.960327 316.33371
65 207 66.250748 207.832001
158 407 158 407
282 461 283.567688 460.905243
53 337 54.0564 334.985413
638 291 638.365051 291.364532
34 477 32.855476 478.484039
162 413 162 413
274 40 274.129211 38.520088
41 277 41 277
407 71 406.617126 70.229546
95 477 95.162102 478.559387
133 477 133 477
225 390 226.661194 389.679596
603 169 603.631226 168.46019
146 467 144.850479 464.238312
174 383 174.595169 382.531189
112 325 111.867439 326.299652
194 388 194 388
58 348 58.941166 349.243073
156 453 157.918381 454.864227
615 213 615.423035 214.50383
178 398 178.002335 397.914215
116 473 117.430855 470.287781
47 329 46.515869 329.850739
44 307 44.659878 305.491821
160 457 157.926819 459.669403
148 415 150.416962 417.023529
145 290 143.436157 290.277985
109 474 109 474
118 447 117.039696 446.002502
139 469 139 469
138 445 140.743973 444.947571
160 310 159.202484 309.343964
153 467 152.075958 468.852844
137 455 134.443466 455.724915
484 420 482.420044 421.416656
143 448 140.511902 445.754517
622 176 622.9776 174.712143
154 448 154 448
150 306 151.808548 305.681183
30 277 30.737091 279.031219
136 439 136 439
165 449 162.291138 450.282227
191 395 191.669235 392.0336
2 229 0.359053 229.453705
95 306 93.769638 306.755463
303 477 303.275635 478.525665
176 389 176 389
140 477 139.243103 478.506836
149 455 149 455
97 438 95.075996 438.308624
638 285 638.268433 284.668304
292 477 292 477
188 401 185.619461 400.684967
70 227 70 227
126 419 126 419
143 438 143 438
610 133 611.076111 132.721558
172 440 172 440
24 247 24.90378 247.919006
158 419 158 419
566 397 566.452209 398.134277
121 410 119.065735 410.2771
33 252 33.511356 251.844849
180 381 178.197098 379.613708
126 452 126 452
183 393 182.582108 392.361359
131 437 131 437
151 420 150.32756 417.153473
128 477 126.419952 478.534943
138 429 138 429
166 394 166.871658 395.072937
217 367 217 367
172 394 170.262985 391.322693
133 451 134.923233 449.34375
135 298 136.869858 298.207581
131 446 131 446
113 454 111.401466 453.746399
142 399 143.115082 397.244324
144 462 145.246246 464.354553
132 462 130.169952 459.457245
182 420 182.27916 419.063446
170 388 170 388
8 255 8.042757 256.647827
605 259 605.310486 257.383911
102 468 100.057426 467.894165
76 155 74.387268 155.617752
2 174 0.527431 173.877594
185 427 185 427
161 463 161 463
280 28 280 28
118 461 116.281197 461.59375
198 393 198 393
140 362 140.18956 361.06958
77 345 75.254028 346.954712
45 323 46.802341 323.090698
156 414 154.80864 411.225403
107 461 105.771194 460.097656
115 467 115 467
107 434 107 434
572 121 570.835999 119.155617
153 478 151.811005 478.576996
122 466 124.632881 466.831177
173 445 171.83699 442.292023
131 406 132.519928 403.895569
207 394 208.327072 392.170074
124 440 122.428673 439.951691
176 327 177.730301 326.282715
176 403 174.62149 400.221405
83 453 82.17395 452.288971
194 407 192.251038 405.181671
144 303 144.42923 301.771515
173 399 173 399
88 458 88 458
128 459 130.425415 458.998322
78 460 76.168289 459.321838
182 401 184.579971 400.85202
5 242 3.816916 243.952225
169 411 169 411
302 442 302 442
82 464 82 464
128 402 127.028763 401.395264
109 423 108.082031 422.247162
115 417 113.579552 416.254883
42 331 42 331
167 400 167 400
201 397 201 397
90 446 88.533951 445.079132
30 304 28.948282 305.937805
121 451 123.440361 448.574249
104 429 102.435143 428.326569
118 421 118 421
36 277 36 277
52 344 54.155262 342.375519
119 221 119 221
155 473 155 473
22 254 22 254
70 469 68.035934 469.233368
172 477 169.329987 478.596527
151 460 153.50676 461.944519
48 337 50.156414 335.978241
215 384 215.199768 385.493744
181 387 181 387
106 443 106 443
278 419 276.92392 419.238892
42 319 42 319
149 447 150.125107 449.818298
190 421 190 421
228 360 230.534348 361.441376
6 247 4.255842 245.215683
185 406 185 406
95 331 95.585266 329.267426
124 471 124 471
46 344 46.258667 343.305542
139 460 139 460
93 450 93 450
184 440 184 440
153 409 154.891968 411.116425
20 235 20 235
139 420 138.211136 420.432587
82 477 80.268921 478.45166
102 448 102 448
24 275 24 275
276 457 275.921661 457.222351
192 477 192 477
634 135 634 135
212 390 212 390
314 477 314.638733 478.578766
179 437 180.079559 436.389618
307 405 308.8909 405.719025
75 340 74.390884 338.975739
150 363 148.123001 363.714539
324 448 325.662994 448.72998
113 427 113 427
133 467 131.354553 464.375366
195 415 195.793442 414.296265
555 449 554.767761 450.06488
53 288 52.229633 289.30661
126 243 124.381767 242.674225
306 446 306 446
302 464 303.366913 465.364105
50 349 50.666424 350.814087
301 437 299.912231 435.25946
21 229 18.846128 227.009109
593 335 592.243591 335.971527
41 314 41 314
157 400 154.883865 400.263031
303 470 305.244904 471.695343
22 269 22 269
22 240 22 240
132 396 130.897324 395.369934
81 243 78.946297 241.783127
297 477 297 477
288 445 288.517487 444.895172
299 432 299 432
168 320 169.037354 318.091766
284 374 284 374
122 457 121.275467 454.710907
88 298 88 298
171 316 169.500443 317.163361
130 415 130 415
225 340 225 340
84 254 83.076866 256.995026
103 145 103 145
221 361 221 361