506 lines
18 KiB
C++
506 lines
18 KiB
C++
#include "cv.h"
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#include "highgui.h"
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#include <stdio.h>
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#include <string.h>
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#include <time.h>
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// example command line (for copy-n-paste):
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// calibration -w 6 -h 8 -s 2 -n 10 -o camera.yml -op -oe [<list_of_views.txt>]
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/* The list of views may look as following (discard the starting and ending ------ separators):
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-------------------
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view000.png
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view001.png
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#view002.png
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view003.png
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view010.png
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one_extra_view.jpg
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-------------------
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that is, the file will contain 6 lines, view002.png will not be used for calibration,
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other ones will be (those, in which the chessboard pattern will be found)
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*/
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enum { DETECTION = 0, CAPTURING = 1, CALIBRATED = 2 };
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double compute_reprojection_error( const CvMat* object_points,
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const CvMat* rot_vects, const CvMat* trans_vects,
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const CvMat* camera_matrix, const CvMat* dist_coeffs,
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const CvMat* image_points, const CvMat* point_counts,
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CvMat* per_view_errors )
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{
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CvMat* image_points2 = cvCreateMat( image_points->rows,
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image_points->cols, image_points->type );
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int i, image_count = rot_vects->rows, points_so_far = 0;
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double total_err = 0, err;
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for( i = 0; i < image_count; i++ )
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{
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CvMat object_points_i, image_points_i, image_points2_i;
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int point_count = point_counts->data.i[i];
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CvMat rot_vect, trans_vect;
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cvGetCols( object_points, &object_points_i,
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points_so_far, points_so_far + point_count );
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cvGetCols( image_points, &image_points_i,
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points_so_far, points_so_far + point_count );
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cvGetCols( image_points2, &image_points2_i,
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points_so_far, points_so_far + point_count );
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points_so_far += point_count;
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cvGetRow( rot_vects, &rot_vect, i );
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cvGetRow( trans_vects, &trans_vect, i );
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cvProjectPoints2( &object_points_i, &rot_vect, &trans_vect,
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camera_matrix, dist_coeffs, &image_points2_i,
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0, 0, 0, 0, 0 );
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err = cvNorm( &image_points_i, &image_points2_i, CV_L1 );
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if( per_view_errors )
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per_view_errors->data.db[i] = err/point_count;
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total_err += err;
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}
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cvReleaseMat( &image_points2 );
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return total_err/points_so_far;
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}
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int run_calibration( CvSeq* image_points_seq, CvSize img_size, CvSize board_size,
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float square_size, float aspect_ratio, int flags,
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CvMat* camera_matrix, CvMat* dist_coeffs, CvMat** extr_params,
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CvMat** reproj_errs, double* avg_reproj_err )
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{
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int code;
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int image_count = image_points_seq->total;
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int point_count = board_size.width*board_size.height;
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CvMat* image_points = cvCreateMat( 1, image_count*point_count, CV_32FC2 );
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CvMat* object_points = cvCreateMat( 1, image_count*point_count, CV_32FC3 );
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CvMat* point_counts = cvCreateMat( 1, image_count, CV_32SC1 );
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CvMat rot_vects, trans_vects;
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int i, j, k;
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CvSeqReader reader;
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cvStartReadSeq( image_points_seq, &reader );
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// initialize arrays of points
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for( i = 0; i < image_count; i++ )
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{
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CvPoint2D32f* src_img_pt = (CvPoint2D32f*)reader.ptr;
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CvPoint2D32f* dst_img_pt = ((CvPoint2D32f*)image_points->data.fl) + i*point_count;
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CvPoint3D32f* obj_pt = ((CvPoint3D32f*)object_points->data.fl) + i*point_count;
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for( j = 0; j < board_size.height; j++ )
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for( k = 0; k < board_size.width; k++ )
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{
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*obj_pt++ = cvPoint3D32f(j*square_size, k*square_size, 0);
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*dst_img_pt++ = *src_img_pt++;
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}
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CV_NEXT_SEQ_ELEM( image_points_seq->elem_size, reader );
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}
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cvSet( point_counts, cvScalar(point_count) );
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*extr_params = cvCreateMat( image_count, 6, CV_32FC1 );
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cvGetCols( *extr_params, &rot_vects, 0, 3 );
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cvGetCols( *extr_params, &trans_vects, 3, 6 );
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cvZero( camera_matrix );
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cvZero( dist_coeffs );
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if( flags & CV_CALIB_FIX_ASPECT_RATIO )
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{
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camera_matrix->data.db[0] = aspect_ratio;
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camera_matrix->data.db[4] = 1.;
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}
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cvCalibrateCamera2( object_points, image_points, point_counts,
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img_size, camera_matrix, dist_coeffs,
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&rot_vects, &trans_vects, flags );
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code = cvCheckArr( camera_matrix, CV_CHECK_QUIET ) &&
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cvCheckArr( dist_coeffs, CV_CHECK_QUIET ) &&
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cvCheckArr( *extr_params, CV_CHECK_QUIET );
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*reproj_errs = cvCreateMat( 1, image_count, CV_64FC1 );
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*avg_reproj_err =
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compute_reprojection_error( object_points, &rot_vects, &trans_vects,
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camera_matrix, dist_coeffs, image_points, point_counts, *reproj_errs );
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cvReleaseMat( &object_points );
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cvReleaseMat( &image_points );
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cvReleaseMat( &point_counts );
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return code;
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}
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void save_camera_params( const char* out_filename, int image_count, CvSize img_size,
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CvSize board_size, float square_size,
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float aspect_ratio, int flags,
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const CvMat* camera_matrix, CvMat* dist_coeffs,
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const CvMat* extr_params, const CvSeq* image_points_seq,
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const CvMat* reproj_errs, double avg_reproj_err )
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{
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CvFileStorage* fs = cvOpenFileStorage( out_filename, 0, CV_STORAGE_WRITE );
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time_t t;
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time( &t );
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struct tm *t2 = localtime( &t );
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char buf[1024];
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strftime( buf, sizeof(buf)-1, "%c", t2 );
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cvWriteString( fs, "calibration_time", buf );
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cvWriteInt( fs, "image_count", image_count );
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cvWriteInt( fs, "image_width", img_size.width );
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cvWriteInt( fs, "image_height", img_size.height );
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cvWriteInt( fs, "board_width", board_size.width );
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cvWriteInt( fs, "board_height", board_size.height );
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cvWriteReal( fs, "square_size", square_size );
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if( flags & CV_CALIB_FIX_ASPECT_RATIO )
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cvWriteReal( fs, "aspect_ratio", aspect_ratio );
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if( flags != 0 )
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{
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sprintf( buf, "flags: %s%s%s%s",
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flags & CV_CALIB_USE_INTRINSIC_GUESS ? "+use_intrinsic_guess" : "",
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flags & CV_CALIB_FIX_ASPECT_RATIO ? "+fix_aspect_ratio" : "",
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flags & CV_CALIB_FIX_PRINCIPAL_POINT ? "+fix_principal_point" : "",
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flags & CV_CALIB_ZERO_TANGENT_DIST ? "+zero_tangent_dist" : "" );
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cvWriteComment( fs, buf, 0 );
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}
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cvWriteInt( fs, "flags", flags );
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cvWrite( fs, "camera_matrix", camera_matrix );
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cvWrite( fs, "distortion_coefficients", dist_coeffs );
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cvWriteReal( fs, "avg_reprojection_error", avg_reproj_err );
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if( reproj_errs )
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cvWrite( fs, "per_view_reprojection_errors", reproj_errs );
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if( extr_params )
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{
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cvWriteComment( fs, "a set of 6-tuples (rotation vector + translation vector) for each view", 0 );
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cvWrite( fs, "extrinsic_parameters", extr_params );
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}
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if( image_points_seq )
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{
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cvWriteComment( fs, "the array of board corners projections used for calibration", 0 );
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assert( image_points_seq->total == image_count );
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CvMat* image_points = cvCreateMat( 1, image_count*board_size.width*board_size.height, CV_32FC2 );
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cvCvtSeqToArray( image_points_seq, image_points->data.fl );
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cvWrite( fs, "image_points", image_points );
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cvReleaseMat( &image_points );
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}
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cvReleaseFileStorage( &fs );
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}
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int main( int argc, char** argv )
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{
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CvSize board_size = {0,0};
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float square_size = 1.f, aspect_ratio = 1.f;
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const char* out_filename = "out_camera_data.yml";
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const char* input_filename = 0;
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int i, image_count = 10;
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int write_extrinsics = 0, write_points = 0;
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int flags = 0;
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CvCapture* capture = 0;
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FILE* f = 0;
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char imagename[1024];
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CvMemStorage* storage;
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CvSeq* image_points_seq = 0;
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int elem_size, flip_vertical = 0;
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int delay = 1000;
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clock_t prev_timestamp = 0;
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CvPoint2D32f* image_points_buf = 0;
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CvFont font = cvFont( 1, 1 );
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double _camera[9], _dist_coeffs[4];
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CvMat camera = cvMat( 3, 3, CV_64F, _camera );
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CvMat dist_coeffs = cvMat( 1, 4, CV_64F, _dist_coeffs );
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CvMat *extr_params = 0, *reproj_errs = 0;
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double avg_reproj_err = 0;
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int mode = DETECTION;
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int undistort_image = 0;
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CvSize img_size = {0,0};
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const char* live_capture_help =
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"When the live video from camera is used as input, the following hot-keys may be used:\n"
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" <ESC>, 'q' - quit the program\n"
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" 'g' - start capturing images\n"
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" 'u' - switch undistortion on/off\n";
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if( argc < 2 )
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{
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printf( "This is a camera calibration sample.\n"
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"Usage: calibration\n"
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" -w <board_width> # the number of inner corners per one of board dimension\n"
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" -h <board_height> # the number of inner corners per another board dimension\n"
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" [-n <number_of_frames>] # the number of frames to use for calibration\n"
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" # (if not specified, it will be set to the number\n"
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" # of board views actually available)\n"
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" [-d <delay>] # a minimum delay in ms between subsequent attempts to capture a next view\n"
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" # (used only for video capturing)\n"
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" [-s <square_size>] # square size in some user-defined units (1 by default)\n"
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" [-o <out_camera_params>] # the output filename for intrinsic [and extrinsic] parameters\n"
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" [-op] # write detected feature points\n"
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" [-oe] # write extrinsic parameters\n"
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" [-zt] # assume zero tangential distortion\n"
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" [-a <aspect_ratio>] # fix aspect ratio (fx/fy)\n"
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" [-p] # fix the principal point at the center\n"
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" [-v] # flip the captured images around the horizontal axis\n"
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" [input_data] # input data, one of the following:\n"
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" # - text file with a list of the images of the board\n"
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" # - name of video file with a video of the board\n"
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" # if input_data not specified, a live view from the camera is used\n"
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"\n" );
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printf( "%s", live_capture_help );
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return 0;
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}
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for( i = 1; i < argc; i++ )
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{
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const char* s = argv[i];
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if( strcmp( s, "-w" ) == 0 )
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{
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if( sscanf( argv[++i], "%u", &board_size.width ) != 1 || board_size.width <= 0 )
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return fprintf( stderr, "Invalid board width\n" ), -1;
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}
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else if( strcmp( s, "-h" ) == 0 )
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{
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if( sscanf( argv[++i], "%u", &board_size.height ) != 1 || board_size.height <= 0 )
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return fprintf( stderr, "Invalid board height\n" ), -1;
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}
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else if( strcmp( s, "-s" ) == 0 )
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{
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if( sscanf( argv[++i], "%f", &square_size ) != 1 || square_size <= 0 )
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return fprintf( stderr, "Invalid board square width\n" ), -1;
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}
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else if( strcmp( s, "-n" ) == 0 )
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{
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if( sscanf( argv[++i], "%u", &image_count ) != 1 || image_count <= 3 )
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return printf("Invalid number of images\n" ), -1;
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}
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else if( strcmp( s, "-a" ) == 0 )
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{
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if( sscanf( argv[++i], "%f", &aspect_ratio ) != 1 || aspect_ratio <= 0 )
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return printf("Invalid aspect ratio\n" ), -1;
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}
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else if( strcmp( s, "-d" ) == 0 )
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{
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if( sscanf( argv[++i], "%u", &delay ) != 1 || delay <= 0 )
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return printf("Invalid delay\n" ), -1;
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}
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else if( strcmp( s, "-op" ) == 0 )
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{
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write_points = 1;
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}
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else if( strcmp( s, "-oe" ) == 0 )
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{
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write_extrinsics = 1;
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}
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else if( strcmp( s, "-zt" ) == 0 )
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{
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flags |= CV_CALIB_ZERO_TANGENT_DIST;
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}
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else if( strcmp( s, "-p" ) == 0 )
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{
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flags |= CV_CALIB_FIX_PRINCIPAL_POINT;
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}
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else if( strcmp( s, "-v" ) == 0 )
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{
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flip_vertical = 1;
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}
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else if( strcmp( s, "-o" ) == 0 )
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{
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out_filename = argv[++i];
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}
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else if( s[0] != '-' )
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input_filename = s;
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else
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return fprintf( stderr, "Unknown option %s", s ), -1;
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}
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if( input_filename )
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{
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capture = cvCreateFileCapture( input_filename );
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if( !capture )
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{
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f = fopen( input_filename, "rt" );
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if( !f )
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return fprintf( stderr, "The input file could not be opened\n" ), -1;
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image_count = -1;
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}
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mode = CAPTURING;
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}
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else
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capture = cvCreateCameraCapture(0);
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if( !capture && !f )
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return fprintf( stderr, "Could not initialize video capture\n" ), -2;
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if( capture )
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printf( "%s", live_capture_help );
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elem_size = board_size.width*board_size.height*sizeof(image_points_buf[0]);
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storage = cvCreateMemStorage( MAX( elem_size*4, 1 << 16 ));
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image_points_buf = (CvPoint2D32f*)cvAlloc( elem_size );
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image_points_seq = cvCreateSeq( 0, sizeof(CvSeq), elem_size, storage );
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cvNamedWindow( "Image View", 1 );
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for(;;)
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{
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IplImage *view = 0, *view_gray = 0;
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int count = 0, found, blink = 0;
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CvPoint text_origin;
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CvSize text_size = {0,0};
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int base_line = 0;
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char s[100];
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int key;
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if( f && fgets( imagename, sizeof(imagename)-2, f ))
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{
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int l = strlen(imagename);
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if( l > 0 && imagename[l-1] == '\n' )
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imagename[--l] = '\0';
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if( l > 0 )
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{
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if( imagename[0] == '#' )
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continue;
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view = cvLoadImage( imagename, 1 );
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}
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}
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else if( capture )
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{
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IplImage* view0 = cvQueryFrame( capture );
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if( view0 )
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{
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view = cvCreateImage( cvGetSize(view0), IPL_DEPTH_8U, view0->nChannels );
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if( view0->origin == IPL_ORIGIN_BL )
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cvFlip( view0, view, 0 );
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else
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cvCopy( view0, view );
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}
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}
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if( !view )
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{
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if( image_points_seq->total > 0 )
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{
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image_count = image_points_seq->total;
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goto calibrate;
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}
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break;
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}
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if( flip_vertical )
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cvFlip( view, view, 0 );
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img_size = cvGetSize(view);
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found = cvFindChessboardCorners( view, board_size,
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image_points_buf, &count, CV_CALIB_CB_ADAPTIVE_THRESH );
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#if 1
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// improve the found corners' coordinate accuracy
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view_gray = cvCreateImage( cvGetSize(view), 8, 1 );
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cvCvtColor( view, view_gray, CV_BGR2GRAY );
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cvFindCornerSubPix( view_gray, image_points_buf, count, cvSize(11,11),
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cvSize(-1,-1), cvTermCriteria( CV_TERMCRIT_EPS+CV_TERMCRIT_ITER, 30, 0.1 ));
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cvReleaseImage( &view_gray );
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#endif
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if( mode == CAPTURING && found && (f || clock() - prev_timestamp > delay*1e-3*CLOCKS_PER_SEC) )
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{
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cvSeqPush( image_points_seq, image_points_buf );
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prev_timestamp = clock();
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blink = !f;
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#if 1
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if( capture )
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{
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sprintf( imagename, "view%03d.png", image_points_seq->total - 1 );
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cvSaveImage( imagename, view );
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}
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#endif
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}
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cvDrawChessboardCorners( view, board_size, image_points_buf, count, found );
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cvGetTextSize( "100/100", &font, &text_size, &base_line );
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text_origin.x = view->width - text_size.width - 10;
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text_origin.y = view->height - base_line - 10;
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if( mode == CAPTURING )
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{
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if( image_count > 0 )
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sprintf( s, "%d/%d", image_points_seq ? image_points_seq->total : 0, image_count );
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else
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sprintf( s, "%d/?", image_points_seq ? image_points_seq->total : 0 );
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}
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else if( mode == CALIBRATED )
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sprintf( s, "Calibrated" );
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else
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sprintf( s, "Press 'g' to start" );
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cvPutText( view, s, text_origin, &font, mode != CALIBRATED ?
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CV_RGB(255,0,0) : CV_RGB(0,255,0));
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if( blink )
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cvNot( view, view );
|
|
|
|
if( mode == CALIBRATED && undistort_image )
|
|
{
|
|
IplImage* t = cvCloneImage( view );
|
|
cvUndistort2( t, view, &camera, &dist_coeffs );
|
|
cvReleaseImage( &t );
|
|
}
|
|
|
|
cvShowImage( "Image View", view );
|
|
key = cvWaitKey(capture ? 50 : 500);
|
|
|
|
if( key == 27 )
|
|
break;
|
|
|
|
if( key == 'u' && mode == CALIBRATED )
|
|
undistort_image = !undistort_image;
|
|
|
|
if( capture && key == 'g' )
|
|
{
|
|
mode = CAPTURING;
|
|
cvClearMemStorage( storage );
|
|
image_points_seq = cvCreateSeq( 0, sizeof(CvSeq), elem_size, storage );
|
|
}
|
|
|
|
if( mode == CAPTURING && (unsigned)image_points_seq->total >= (unsigned)image_count )
|
|
{
|
|
calibrate:
|
|
cvReleaseMat( &extr_params );
|
|
cvReleaseMat( &reproj_errs );
|
|
int code = run_calibration( image_points_seq, img_size, board_size,
|
|
square_size, aspect_ratio, flags, &camera, &dist_coeffs, &extr_params,
|
|
&reproj_errs, &avg_reproj_err );
|
|
// save camera parameters in any case, to catch Inf's/NaN's
|
|
save_camera_params( out_filename, image_count, img_size,
|
|
board_size, square_size, aspect_ratio, flags,
|
|
&camera, &dist_coeffs, write_extrinsics ? extr_params : 0,
|
|
write_points ? image_points_seq : 0, reproj_errs, avg_reproj_err );
|
|
if( code )
|
|
mode = CALIBRATED;
|
|
else
|
|
mode = DETECTION;
|
|
}
|
|
|
|
if( !view )
|
|
break;
|
|
cvReleaseImage( &view );
|
|
}
|
|
|
|
if( capture )
|
|
cvReleaseCapture( &capture );
|
|
if( storage )
|
|
cvReleaseMemStorage( &storage );
|
|
return 0;
|
|
}
|