代码是我几个月前，不知道哪里下载的，原始版权不在我，也没法给出处。
opencv做相机标定经常碰到问题，就是超大图片无法找到角点。我做了小修改，就是把图片先缩小，等找到角点了，再放大到原来比例。
输入参数：
方格的数量，注意是内圈角点数量 boardsize
方格的物理 尺寸，单位毫米 squaresize
CMakeLists:
cmake_minimum_required(VERSION 2.8)
project( Calibrate )
find_package( OpenCV REQUIRED )
include_directories(toolFunction.h)
add_executable( Calibrate camera.cpp toolFunction.cpp)
target_link_libraries( Calibrate ${OpenCV_LIBS} )
camera.cpp
#include<iostream>
#include <vector>
#include <string>
#include <opencv2/photo.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/calib3d/calib3d.hpp>
#include "toolFunction.h"
#define DEBUG_OUTPUT_INFO
using namespace std;
using namespace cv;
int main()
{
//char* folderPath = "E:/Images/New"; // image folder
//std::vector<std::string> graphPaths;
std::vector<std::string> graphSuccess;
char mypath[50];
CalibrationAssist calAssist;
cv::Size msize(600,400); //for resolution 6000*4000
int downsize = 10; //downsize scale factor
//graphPaths = calAssist.get_filelist(folderPath); // collect image list
std::cout << "Start corner detection ..." << std::endl;
cv::Mat curGraph; // current image
cv::Mat gray; // gray image of current image
cv::Mat small; // temp file to downsize the image
int imageCount = 12;
int imageCountSuccess = 0;
cv::Size image_size;
cv::Size boardSize = cv::Size(7, 5); // chess board pattern size,only compute the inside square!!
cv::Size squareSize = cv::Size(30, 30); // grid physical size, as a scale factor
std::vector<cv::Point2f> corners; // one image corner list
std::vector<std::vector<cv::Point2f> > seqCorners; // n images corner list
for ( int i=1; i<=imageCount; i++ )
{
sprintf(mypath,"/home/jst/Data/gezi/%03d.jpg", i);
std::cout<<mypath<<endl;
curGraph = cv::imread(mypath);
cv::resize(curGraph, small, msize);
if ( curGraph.channels() == 3 )
cv::cvtColor( curGraph, gray, CV_BGR2GRAY );
else
curGraph.copyTo( gray );
// for every image, empty the corner list
std::vector<cv::Point2f>().swap( corners );
// corners detection
bool success = cv::findChessboardCorners( small, boardSize, corners );
if ( success ) // succeed
{
std::cout << i << " " << mypath << " succeed"<< std::endl;
int row = curGraph.rows;
int col = curGraph.cols;
imageCountSuccess ++;
image_size = cv::Size( col, row );
//rectify the corner
for(size_t j=0;j<corners.size();j++)
{
corners[j].x = corners[j].x*downsize;
corners[j].y = corners[j].y*downsize;
}
// find sub-pixels
cv::cornerSubPix(
gray,
corners,
cv::Size( 11, 11 ),
cv::Size( -1, -1 ),
cv::TermCriteria( CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 30, 0.1 ) );
seqCorners.push_back( corners );
// draw corners and show them in current image
cv::Mat imageDrawCorners;
if ( curGraph.channels() == 3 )
curGraph.copyTo( imageDrawCorners );
else
cv::cvtColor( curGraph, imageDrawCorners, CV_GRAY2RGB );
for ( int j = 0; j < corners.size(); j ++)
{
cv::Point2f dotPoint = corners[j];
cv::circle( imageDrawCorners, dotPoint, 3.0, cv::Scalar( 0, 255, 0 ), -1 );
cv::Point2f pt_m = dotPoint + cv::Point2f(4,4);
char text[100];
sprintf( text, "%d", j+1 ); // corner indexes which start from 1
cv::putText( imageDrawCorners, text, pt_m, 1, 0.5, cv::Scalar( 255, 0, 255 ) );
}
sprintf(mypath,"./corners_%d.jpg",i);
// save image drawn with corners and labeled with indexes
cv::imwrite( mypath, imageDrawCorners );
}
else // failed
{
std::cout << mypath << " corner detect failed!" << std::endl;
}
}
std::cout << "Corner detect done!" << std::endl
<< imageCountSuccess << " succeed! " << std::endl;
if ( imageCountSuccess < 3 )
{
std::cout << "Calibrated success " << imageCountSuccess
<< " images, less than 3 images." << std::endl;
return 0;
}
else
{
std::cout << "Start calibration ..." << std::endl;
cv::Point3f point3D;
std::vector<cv::Point3f> objectPoints;
std::vector<double> distCoeffs;
std::vector<double> rotation;
std::vector<double> translation;
std::vector<std::vector<cv::Point3f> > seqObjectPoints;
std::vector<std::vector<double> > seqRotation;
std::vector<std::vector<double> > seqTranslation;
cv::Mat_<double> cameraMatrix;
// calibration pattern points in the calibration pattern coordinate space
for ( int t=0; t<imageCountSuccess; t++ )
{
objectPoints.clear();
for ( int i=0; i<boardSize.height; i++ )
{
for ( int j=0; j<boardSize.width; j++ )
{
point3D.x = i * squareSize.width;
point3D.y = j * squareSize.height;
point3D.z = 0;
objectPoints.push_back(point3D);
}
}
seqObjectPoints.push_back(objectPoints);
}
double reprojectionError = calibrateCamera(
seqObjectPoints,
seqCorners,
image_size,
cameraMatrix,
distCoeffs,
seqRotation,
seqTranslation,
CV_CALIB_FIX_ASPECT_RATIO|CV_CALIB_FIX_PRINCIPAL_POINT );
std::cout << "Calibration done!" << std::endl;
// calculate the calibration pattern points with the camera model
std::vector<cv::Mat_<double> > projectMats;
for ( int i=0; i<imageCountSuccess; i++ )
{
cv::Mat_<double> R, T;
// translate rotation vector to rotation matrix via Rodrigues transformation
cv::Rodrigues( seqRotation[i], R );
T = cv::Mat( cv::Matx31d(
seqTranslation[i][0],
seqTranslation[i][1],
seqTranslation[i][2]) );
cv::Mat_<double> P = cameraMatrix * cv::Mat( cv::Matx34d(
R(0,0), R(0,1), R(0,2), T(0),
R(1,0), R(1,1), R(1,2), T(1),
R(2,0), R(2,1), R(2,2), T(2) ) );
projectMats.push_back(P);
}
std::vector<cv::Point2d> PointSet;
int pointNum = boardSize.width*boardSize.height;
std::vector<cv::Point3d> objectClouds;
for ( int i=0; i<pointNum; i++ )
{
PointSet.clear();
for ( int j=0; j<imageCountSuccess; j++ )
{
cv::Point2d tempPoint = seqCorners[j][i];
PointSet.push_back(tempPoint);
}
// calculate calibration pattern points
cv::Point3d objectPoint = calAssist.triangulate(projectMats,PointSet);
objectClouds.push_back(objectPoint);
}
std::string pathTemp_point;
pathTemp_point = ".";
pathTemp_point += "/point.txt";
calAssist.save3dPoint(pathTemp_point,objectClouds);
std::string pathTemp_calib;
pathTemp_calib = ".";
pathTemp_calib += "/calibration.txt";
FILE* fp = fopen( pathTemp_calib.c_str(), "w" );
fprintf( fp, "The average of re-projection error : %lf\n", reprojectionError );
for ( int i=0; i<imageCountSuccess; i++ )
{
std::vector<cv::Point2f> errorList;
cv::projectPoints(
seqObjectPoints[i],
seqRotation[i],
seqTranslation[i],
cameraMatrix,
distCoeffs,
errorList );
corners.clear();
corners = seqCorners[i];
double meanError(0.0);
for ( int j=0; j<corners.size(); j++ )
{
meanError += std::sqrt((errorList[j].x - corners[j].x)*(errorList[j].x - corners[j].x) +
(errorList[j].y - corners[j].y)*(errorList[j].y - corners[j].y));
}
rotation.clear();
translation.clear();
rotation = seqRotation[i];
translation = seqTranslation[i];
fprintf( fp, "Re-projection of image %d：%lf\n", i+1, meanError/corners.size() );
fprintf( fp, "Rotation vector :\n" );
fprintf( fp, "%lf %lf %lf\n", rotation[0], rotation[1], rotation[2] );
fprintf( fp, "Translation vector :\n" );
fprintf( fp, "%lf %lf %lf\n\n", translation[0], translation[1], translation[2] );
}
fprintf( fp, "Camera internal matrix :\n" );
fprintf( fp, "%lf %lf %lf\n%lf %lf %lf\n%lf %lf %lf\n",
cameraMatrix(0,0), cameraMatrix(0,1), cameraMatrix(0,2),
cameraMatrix(1,0), cameraMatrix(1,1), cameraMatrix(1,2),
cameraMatrix(2,0), cameraMatrix(2,1), cameraMatrix(2,2));
fprintf( fp,"Distortion coefficient :\n" );
for ( int k=0; k<distCoeffs.size(); k++)
fprintf( fp, "%lf ", distCoeffs[k] );
std::cout << "Results are saved!" << std::endl;
}
return 0;
}
toolFunction.cpp
#include "toolFunction.h"
cv::Point3d CalibrationAssist::triangulate(
std::vector<cv::Mat_<double> > &ProjectMats,
std::vector<cv::Point2d> &imagePoints)
{
int i,j;
std::vector<cv::Point2d> pointSet;
int frameSum = ProjectMats.size();
cv::Mat A(2*frameSum,3,CV_32FC1);
cv::Mat B(2*frameSum,1,CV_32FC1);
cv::Point2d u,u1;
cv::Mat_<double> P;
cv::Mat_<double> rowA1,rowA2,rowB1,rowB2;
int k = 0;
for ( i = 0; i < frameSum; i++ ) //get the coefficient matrix A and B
{
u = imagePoints[i];
P = ProjectMats[i];
cv::Mat( cv::Matx13d(
u.x*P(2,0)-P(0,0),
u.x*P(2,1)-P(0,1),
u.x*P(2,2)-P(0,2) ) ).copyTo( A.row(k) );
cv::Mat( cv::Matx13d(
u.y*P(2,0)-P(1,0),
u.y*P(2,1)-P(1,1),
u.y*P(2,2)-P(1,2) ) ).copyTo( A.row(k+1) );
cv::Mat rowB1( 1, 1, CV_32FC1, cv::Scalar( -(u.x*P(2,3)-P(0,3)) ) );
cv::Mat rowB2( 1, 1, CV_32FC1, cv::Scalar(-(u.y*P(2,3)-P(1,3)) ) );
rowB1.copyTo( B.row(k) );
rowB2.copyTo( B.row(k+1) );
k += 2;
}
cv::Mat X;
cv::solve( A, B, X, DECOMP_SVD );
return Point3d(X);
}
void CalibrationAssist::save3dPoint( std::string path_, std::vector<cv::Point3d> &Point3dLists)
{
const char * path = path_.c_str();
FILE* fp = fopen( path, "w" );
for ( int i = 0; i < Point3dLists.size(); i ++)
{
// fprintf(fp,"%d ",i);
fprintf( fp, "%lf %lf %lf\n",
Point3dLists[i].x, Point3dLists[i].y, Point3dLists[i].z);
}
fclose(fp);
#if 1
std::cout << "clouds of points are saved!" << std::endl;
#endif
}
#ifndef TOOL_FUNCTION_H
#pragma once
#define TOOL_FUNCTION_H
#include<iostream>
#include <math.h>
#include <fstream>
#include <vector>
#include <string>
#include <opencv2/photo.hpp>
#include <opencv2/highgui.hpp>
using namespace cv;
using namespace std;
class CalibrationAssist
{
public:
CalibrationAssist() {}
~CalibrationAssist() {}
public:
cv::Point3d triangulate( std::vector<cv::Mat_<double> > &ProjectMats,
std::vector<cv::Point2d> &imagePoints );
void save3dPoint( std::string path_, std::vector<cv::Point3d> &Point3dLists );
};
#endif // TOOL_FUNCTION_H
Camera internal matrix :
11964.095146 0.000000 2999.500000
0.000000 11964.095146 1999.500000
0.000000 0.000000 1.000000
Distortion coefficient :
0.163781 6.243557 -0.000678 0.000548 -190.849777
这图可是6000*4000分辨率！我缩小的10倍做的