1 /* This is sample from the OpenCV book. The copyright notice is below */
2
3 /* *************** License:**************************
4 Oct. 3, 2008
5 Right to use this code in any way you want without warranty, support or any guarantee of it working.
6
7 BOOK: It would be nice if you cited it:
8 Learning OpenCV: Computer Vision with the OpenCV Library
9 by Gary Bradski and Adrian Kaehler
10 Published by O'Reilly Media, October 3, 2008
11
12 AVAILABLE AT:
13 http://www.amazon.com/Learning-OpenCV-Computer-Vision-Library/dp/0596516134
14 Or: http://oreilly.com/catalog/9780596516130/
15 ISBN-10: 0596516134 or: ISBN-13: 978-0596516130
16
17 OPENCV WEBSITES:
18 Homepage: http://opencv.org
19 Online docs: http://docs.opencv.org
20 Q&A forum: http://answers.opencv.org
21 Issue tracker: http://code.opencv.org
22 GitHub: https://github.com/Itseez/opencv/
23 ************************************************** */
24
25 #include "opencv2/calib3d/calib3d.hpp"
26 #include "opencv2/imgcodecs.hpp"
27 #include "opencv2/highgui/highgui.hpp"
28 #include "opencv2/imgproc/imgproc.hpp"
29
30 #include <vector>
31 #include <string>
32 #include <algorithm>
33 #include <iostream>
34 #include <iterator>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <ctype.h>
38
39 using namespace cv;
40 using namespace std;
41
print_help()42 static int print_help()
43 {
44 cout <<
45 " Given a list of chessboard images, the number of corners (nx, ny)\n"
46 " on the chessboards, and a flag: useCalibrated for \n"
47 " calibrated (0) or\n"
48 " uncalibrated \n"
49 " (1: use cvStereoCalibrate(), 2: compute fundamental\n"
50 " matrix separately) stereo. \n"
51 " Calibrate the cameras and display the\n"
52 " rectified results along with the computed disparity images. \n" << endl;
53 cout << "Usage:\n ./stereo_calib -w board_width -h board_height [-nr /*dot not view results*/] <image list XML/YML file>\n" << endl;
54 return 0;
55 }
56
57
58 static void
StereoCalib(const vector<string> & imagelist,Size boardSize,bool useCalibrated=true,bool showRectified=true)59 StereoCalib(const vector<string>& imagelist, Size boardSize, bool useCalibrated=true, bool showRectified=true)
60 {
61 if( imagelist.size() % 2 != 0 )
62 {
63 cout << "Error: the image list contains odd (non-even) number of elements\n";
64 return;
65 }
66
67 bool displayCorners = false;//true;
68 const int maxScale = 2;
69 const float squareSize = 1.f; // Set this to your actual square size
70 // ARRAY AND VECTOR STORAGE:
71
72 vector<vector<Point2f> > imagePoints[2];
73 vector<vector<Point3f> > objectPoints;
74 Size imageSize;
75
76 int i, j, k, nimages = (int)imagelist.size()/2;
77
78 imagePoints[0].resize(nimages);
79 imagePoints[1].resize(nimages);
80 vector<string> goodImageList;
81
82 for( i = j = 0; i < nimages; i++ )
83 {
84 for( k = 0; k < 2; k++ )
85 {
86 const string& filename = imagelist[i*2+k];
87 Mat img = imread(filename, 0);
88 if(img.empty())
89 break;
90 if( imageSize == Size() )
91 imageSize = img.size();
92 else if( img.size() != imageSize )
93 {
94 cout << "The image " << filename << " has the size different from the first image size. Skipping the pair\n";
95 break;
96 }
97 bool found = false;
98 vector<Point2f>& corners = imagePoints[k][j];
99 for( int scale = 1; scale <= maxScale; scale++ )
100 {
101 Mat timg;
102 if( scale == 1 )
103 timg = img;
104 else
105 resize(img, timg, Size(), scale, scale);
106 found = findChessboardCorners(timg, boardSize, corners,
107 CALIB_CB_ADAPTIVE_THRESH | CALIB_CB_NORMALIZE_IMAGE);
108 if( found )
109 {
110 if( scale > 1 )
111 {
112 Mat cornersMat(corners);
113 cornersMat *= 1./scale;
114 }
115 break;
116 }
117 }
118 if( displayCorners )
119 {
120 cout << filename << endl;
121 Mat cimg, cimg1;
122 cvtColor(img, cimg, COLOR_GRAY2BGR);
123 drawChessboardCorners(cimg, boardSize, corners, found);
124 double sf = 640./MAX(img.rows, img.cols);
125 resize(cimg, cimg1, Size(), sf, sf);
126 imshow("corners", cimg1);
127 char c = (char)waitKey(500);
128 if( c == 27 || c == 'q' || c == 'Q' ) //Allow ESC to quit
129 exit(-1);
130 }
131 else
132 putchar('.');
133 if( !found )
134 break;
135 cornerSubPix(img, corners, Size(11,11), Size(-1,-1),
136 TermCriteria(TermCriteria::COUNT+TermCriteria::EPS,
137 30, 0.01));
138 }
139 if( k == 2 )
140 {
141 goodImageList.push_back(imagelist[i*2]);
142 goodImageList.push_back(imagelist[i*2+1]);
143 j++;
144 }
145 }
146 cout << j << " pairs have been successfully detected.\n";
147 nimages = j;
148 if( nimages < 2 )
149 {
150 cout << "Error: too little pairs to run the calibration\n";
151 return;
152 }
153
154 imagePoints[0].resize(nimages);
155 imagePoints[1].resize(nimages);
156 objectPoints.resize(nimages);
157
158 for( i = 0; i < nimages; i++ )
159 {
160 for( j = 0; j < boardSize.height; j++ )
161 for( k = 0; k < boardSize.width; k++ )
162 objectPoints[i].push_back(Point3f(k*squareSize, j*squareSize, 0));
163 }
164
165 cout << "Running stereo calibration ...\n";
166
167 Mat cameraMatrix[2], distCoeffs[2];
168 cameraMatrix[0] = Mat::eye(3, 3, CV_64F);
169 cameraMatrix[1] = Mat::eye(3, 3, CV_64F);
170 Mat R, T, E, F;
171
172 double rms = stereoCalibrate(objectPoints, imagePoints[0], imagePoints[1],
173 cameraMatrix[0], distCoeffs[0],
174 cameraMatrix[1], distCoeffs[1],
175 imageSize, R, T, E, F,
176 CALIB_FIX_ASPECT_RATIO +
177 CALIB_ZERO_TANGENT_DIST +
178 CALIB_SAME_FOCAL_LENGTH +
179 CALIB_RATIONAL_MODEL +
180 CALIB_FIX_K3 + CALIB_FIX_K4 + CALIB_FIX_K5,
181 TermCriteria(TermCriteria::COUNT+TermCriteria::EPS, 100, 1e-5) );
182 cout << "done with RMS error=" << rms << endl;
183
184 // CALIBRATION QUALITY CHECK
185 // because the output fundamental matrix implicitly
186 // includes all the output information,
187 // we can check the quality of calibration using the
188 // epipolar geometry constraint: m2^t*F*m1=0
189 double err = 0;
190 int npoints = 0;
191 vector<Vec3f> lines[2];
192 for( i = 0; i < nimages; i++ )
193 {
194 int npt = (int)imagePoints[0][i].size();
195 Mat imgpt[2];
196 for( k = 0; k < 2; k++ )
197 {
198 imgpt[k] = Mat(imagePoints[k][i]);
199 undistortPoints(imgpt[k], imgpt[k], cameraMatrix[k], distCoeffs[k], Mat(), cameraMatrix[k]);
200 computeCorrespondEpilines(imgpt[k], k+1, F, lines[k]);
201 }
202 for( j = 0; j < npt; j++ )
203 {
204 double errij = fabs(imagePoints[0][i][j].x*lines[1][j][0] +
205 imagePoints[0][i][j].y*lines[1][j][1] + lines[1][j][2]) +
206 fabs(imagePoints[1][i][j].x*lines[0][j][0] +
207 imagePoints[1][i][j].y*lines[0][j][1] + lines[0][j][2]);
208 err += errij;
209 }
210 npoints += npt;
211 }
212 cout << "average reprojection err = " << err/npoints << endl;
213
214 // save intrinsic parameters
215 FileStorage fs("../data/intrinsics.yml", FileStorage::WRITE);
216 if( fs.isOpened() )
217 {
218 fs << "M1" << cameraMatrix[0] << "D1" << distCoeffs[0] <<
219 "M2" << cameraMatrix[1] << "D2" << distCoeffs[1];
220 fs.release();
221 }
222 else
223 cout << "Error: can not save the intrinsic parameters\n";
224
225 Mat R1, R2, P1, P2, Q;
226 Rect validRoi[2];
227
228 stereoRectify(cameraMatrix[0], distCoeffs[0],
229 cameraMatrix[1], distCoeffs[1],
230 imageSize, R, T, R1, R2, P1, P2, Q,
231 CALIB_ZERO_DISPARITY, 1, imageSize, &validRoi[0], &validRoi[1]);
232
233 fs.open("extrinsics.yml", FileStorage::WRITE);
234 if( fs.isOpened() )
235 {
236 fs << "R" << R << "T" << T << "R1" << R1 << "R2" << R2 << "P1" << P1 << "P2" << P2 << "Q" << Q;
237 fs.release();
238 }
239 else
240 cout << "Error: can not save the extrinsic parameters\n";
241
242 // OpenCV can handle left-right
243 // or up-down camera arrangements
244 bool isVerticalStereo = fabs(P2.at<double>(1, 3)) > fabs(P2.at<double>(0, 3));
245
246 // COMPUTE AND DISPLAY RECTIFICATION
247 if( !showRectified )
248 return;
249
250 Mat rmap[2][2];
251 // IF BY CALIBRATED (BOUGUET'S METHOD)
252 if( useCalibrated )
253 {
254 // we already computed everything
255 }
256 // OR ELSE HARTLEY'S METHOD
257 else
258 // use intrinsic parameters of each camera, but
259 // compute the rectification transformation directly
260 // from the fundamental matrix
261 {
262 vector<Point2f> allimgpt[2];
263 for( k = 0; k < 2; k++ )
264 {
265 for( i = 0; i < nimages; i++ )
266 std::copy(imagePoints[k][i].begin(), imagePoints[k][i].end(), back_inserter(allimgpt[k]));
267 }
268 F = findFundamentalMat(Mat(allimgpt[0]), Mat(allimgpt[1]), FM_8POINT, 0, 0);
269 Mat H1, H2;
270 stereoRectifyUncalibrated(Mat(allimgpt[0]), Mat(allimgpt[1]), F, imageSize, H1, H2, 3);
271
272 R1 = cameraMatrix[0].inv()*H1*cameraMatrix[0];
273 R2 = cameraMatrix[1].inv()*H2*cameraMatrix[1];
274 P1 = cameraMatrix[0];
275 P2 = cameraMatrix[1];
276 }
277
278 //Precompute maps for cv::remap()
279 initUndistortRectifyMap(cameraMatrix[0], distCoeffs[0], R1, P1, imageSize, CV_16SC2, rmap[0][0], rmap[0][1]);
280 initUndistortRectifyMap(cameraMatrix[1], distCoeffs[1], R2, P2, imageSize, CV_16SC2, rmap[1][0], rmap[1][1]);
281
282 Mat canvas;
283 double sf;
284 int w, h;
285 if( !isVerticalStereo )
286 {
287 sf = 600./MAX(imageSize.width, imageSize.height);
288 w = cvRound(imageSize.width*sf);
289 h = cvRound(imageSize.height*sf);
290 canvas.create(h, w*2, CV_8UC3);
291 }
292 else
293 {
294 sf = 300./MAX(imageSize.width, imageSize.height);
295 w = cvRound(imageSize.width*sf);
296 h = cvRound(imageSize.height*sf);
297 canvas.create(h*2, w, CV_8UC3);
298 }
299
300 for( i = 0; i < nimages; i++ )
301 {
302 for( k = 0; k < 2; k++ )
303 {
304 Mat img = imread(goodImageList[i*2+k], 0), rimg, cimg;
305 remap(img, rimg, rmap[k][0], rmap[k][1], INTER_LINEAR);
306 cvtColor(rimg, cimg, COLOR_GRAY2BGR);
307 Mat canvasPart = !isVerticalStereo ? canvas(Rect(w*k, 0, w, h)) : canvas(Rect(0, h*k, w, h));
308 resize(cimg, canvasPart, canvasPart.size(), 0, 0, INTER_AREA);
309 if( useCalibrated )
310 {
311 Rect vroi(cvRound(validRoi[k].x*sf), cvRound(validRoi[k].y*sf),
312 cvRound(validRoi[k].width*sf), cvRound(validRoi[k].height*sf));
313 rectangle(canvasPart, vroi, Scalar(0,0,255), 3, 8);
314 }
315 }
316
317 if( !isVerticalStereo )
318 for( j = 0; j < canvas.rows; j += 16 )
319 line(canvas, Point(0, j), Point(canvas.cols, j), Scalar(0, 255, 0), 1, 8);
320 else
321 for( j = 0; j < canvas.cols; j += 16 )
322 line(canvas, Point(j, 0), Point(j, canvas.rows), Scalar(0, 255, 0), 1, 8);
323 imshow("rectified", canvas);
324 char c = (char)waitKey();
325 if( c == 27 || c == 'q' || c == 'Q' )
326 break;
327 }
328 }
329
330
readStringList(const string & filename,vector<string> & l)331 static bool readStringList( const string& filename, vector<string>& l )
332 {
333 l.resize(0);
334 FileStorage fs(filename, FileStorage::READ);
335 if( !fs.isOpened() )
336 return false;
337 FileNode n = fs.getFirstTopLevelNode();
338 if( n.type() != FileNode::SEQ )
339 return false;
340 FileNodeIterator it = n.begin(), it_end = n.end();
341 for( ; it != it_end; ++it )
342 l.push_back((string)*it);
343 return true;
344 }
345
main(int argc,char ** argv)346 int main(int argc, char** argv)
347 {
348 Size boardSize;
349 string imagelistfn;
350 bool showRectified = true;
351
352 for( int i = 1; i < argc; i++ )
353 {
354 if( string(argv[i]) == "-w" )
355 {
356 if( sscanf(argv[++i], "%d", &boardSize.width) != 1 || boardSize.width <= 0 )
357 {
358 cout << "invalid board width" << endl;
359 return print_help();
360 }
361 }
362 else if( string(argv[i]) == "-h" )
363 {
364 if( sscanf(argv[++i], "%d", &boardSize.height) != 1 || boardSize.height <= 0 )
365 {
366 cout << "invalid board height" << endl;
367 return print_help();
368 }
369 }
370 else if( string(argv[i]) == "-nr" )
371 showRectified = false;
372 else if( string(argv[i]) == "--help" )
373 return print_help();
374 else if( argv[i][0] == '-' )
375 {
376 cout << "invalid option " << argv[i] << endl;
377 return 0;
378 }
379 else
380 imagelistfn = argv[i];
381 }
382
383 if( imagelistfn == "" )
384 {
385 imagelistfn = "../data/stereo_calib.xml";
386 boardSize = Size(9, 6);
387 }
388 else if( boardSize.width <= 0 || boardSize.height <= 0 )
389 {
390 cout << "if you specified XML file with chessboards, you should also specify the board width and height (-w and -h options)" << endl;
391 return 0;
392 }
393
394 vector<string> imagelist;
395 bool ok = readStringList(imagelistfn, imagelist);
396 if(!ok || imagelist.empty())
397 {
398 cout << "can not open " << imagelistfn << " or the string list is empty" << endl;
399 return print_help();
400 }
401
402 StereoCalib(imagelist, boardSize, true, showRectified);
403 return 0;
404 }
405