/*------------------------------------------------------------------------------------------*\
This file contains material supporting chapter 11 of the book:
OpenCV3 Computer Vision Application Programming Cookbook
Third Edition
by Robert Laganiere, Packt Publishing, 2016.
This program is free software; permission is hereby granted to use, copy, modify,
and distribute this source code, or portions thereof, for any purpose, without fee,
subject to the restriction that the copyright notice may not be removed
or altered from any source or altered source distribution.
The software is released on an as-is basis and without any warranties of any kind.
In particular, the software is not guaranteed to be fault-tolerant or free from failure.
The author disclaims all warranties with regard to this software, any use,
and any consequent failure, is purely the responsibility of the user.
Copyright (C) 2016 Robert Laganiere, www.laganiere.name
\*------------------------------------------------------------------------------------------*/
#ifndef CAMERACALIBRATOR_H
#define CAMERACALIBRATOR_H
#include <vector>
#include <iostream>
#include <opencv2/core.hpp>
#include "opencv2/imgproc.hpp"
#include "opencv2/calib3d.hpp"
#include <opencv2/highgui.hpp>
class CameraCalibrator {
// input points:
// the points in world coordinates
// (each square is one unit)
std::vector<std::vector<cv::Point3f> > objectPoints;
// the image point positions in pixels
std::vector<std::vector<cv::Point2f> > imagePoints;
// output Matrices
cv::Mat cameraMatrix;
cv::Mat distCoeffs;
// flag to specify how calibration is done
int flag;
// used in image undistortion
cv::Mat map1,map2;
bool mustInitUndistort;
public:
CameraCalibrator() : flag(0), mustInitUndistort(true) {}
// Open the chessboard images and extract corner points
int addChessboardPoints(const std::vector<std::string>& filelist, cv::Size & boardSize, std::string windowName="");
// Add scene points and corresponding image points
void addPoints(const std::vector<cv::Point2f>& imageCorners, const std::vector<cv::Point3f>& objectCorners);
// Calibrate the camera
double calibrate(const cv::Size imageSize);
// Set the calibration flag
void setCalibrationFlag(bool radial8CoeffEnabled=false, bool tangentialParamEnabled=false);
// Remove distortion in an image (after calibration)
cv::Mat remap(const cv::Mat &image, cv::Size &outputSize );
// Getters
cv::Mat getCameraMatrix() { return cameraMatrix; }
cv::Mat getDistCoeffs() { return distCoeffs; }
};
#endif // CAMERACALIBRATOR_H
/*------------------------------------------------------------------------------------------*\
This file contains material supporting chapter 11 of the book:
OpenCV3 Computer Vision Application Programming Cookbook
Third Edition
by Robert Laganiere, Packt Publishing, 2016.
This program is free software; permission is hereby granted to use, copy, modify,
and distribute this source code, or portions thereof, for any purpose, without fee,
subject to the restriction that the copyright notice may not be removed
or altered from any source or altered source distribution.
The software is released on an as-is basis and without any warranties of any kind.
In particular, the software is not guaranteed to be fault-tolerant or free from failure.
The author disclaims all warranties with regard to this software, any use,
and any consequent failure, is purely the responsibility of the user.
Copyright (C) 2016 Robert Laganiere, www.laganiere.name
\*------------------------------------------------------------------------------------------*/
#include "CameraCalibrator.h"
// Open chessboard images and extract corner points
int CameraCalibrator::addChessboardPoints(
const std::vector<std::string>& filelist, // list of filenames containing board images
cv::Size & boardSize, // size of the board
std::string windowName) { // name of window to display results
// if null, no display shown
// the points on the chessboard
std::vector<cv::Point2f> imageCorners;
std::vector<cv::Point3f> objectCorners;
// 3D Scene Points:
// Initialize the chessboard corners
// in the chessboard reference frame
// The corners are at 3D location (X,Y,Z)= (i,j,0)
for (int i=0; i<boardSize.height; i++) {
for (int j=0; j<boardSize.width; j++) {
objectCorners.push_back(cv::Point3f(i, j, 0.0f));
}
}
// 2D Image points:
cv::Mat image; // to contain chessboard image
int successes = 0;
// for all viewpoints
for (int i=0; i<filelist.size(); i++) {
// Open the image
image = cv::imread(filelist[i],0);
// Get the chessboard corners
bool found = cv::findChessboardCorners(image, // image of chessboard pattern
boardSize, // size of pattern
imageCorners); // list of detected corners
// Get subpixel accuracy on the corners
if (found) {
cv::cornerSubPix(image, imageCorners,
cv::Size(5, 5), // half size of serach window
cv::Size(-1, -1),
cv::TermCriteria(cv::TermCriteria::MAX_ITER +
cv::TermCriteria::EPS,
30, // max number of iterations
0.1)); // min accuracy
// If we have a good board, add it to our data
if (imageCorners.size() == boardSize.area()) {
// Add image and scene points from one view
addPoints(imageCorners, objectCorners);
successes++;
}
}
if (windowName.length()>0 && imageCorners.size() == boardSize.area()) {
//Draw the corners
cv::drawChessboardCorners(image, boardSize, imageCorners, found);
cv::imshow(windowName, image);
cv::waitKey(500);
}
}
return successes;
}
// Add scene points and corresponding image points
void CameraCalibrator::addPoints(const std::vector<cv::Point2f>& imageCorners, const std::vector<cv::Point3f>& objectCorners) {
// 2D image points from one view
imagePoints.push_back(imageCorners);
// corresponding 3D scene points
objectPoints.push_back(objectCorners);
}
// Calibrate the camera
// returns the re-projection error
double CameraCalibrator::calibrate(const cv::Size imageSize)
{
// undistorter must be reinitialized
mustInitUndistort= true;
//Output rotations and translations
std::vector<cv::Mat> rvecs, tvecs;
// start calibration
return
cv::calibrateCamera(objectPoints, // the 3D points
imagePoints, // the image points
imageSize, // image size
cameraMatrix, // output camera matrix
distCoeffs, // output distortion matrix
rvecs, tvecs, // Rs, Ts
CV_CALIB_USE_INTRINSIC_GUESS ); // set options
// ,CV_CALIB_USE_INTRINSIC_GUESS);
}
// remove distortion in an image (after calibration)
cv::Mat CameraCalibrator::remap(const cv::Mat &image, cv::Size &outputSize) {
cv::Mat undistorted;
if (outputSize.height == -1)
outputSize = image.size();
if (mustInitUndistort) { // called once per calibration
// cv::Mat dist = (cv::Mat_<double>(1, 14) << -107.8067046233813, 3606.394522865697, -0.003208480233032964, 0.00212257161649465, -706.3301131023582, -107.3590793091425, 3559.830030448713, 855.5629043718579, 0, 0, 0, 0, 0, 0);
// dist = distCoeffs;
cv::initUndistortRectifyMap(
cameraMatrix, // computed camera matrix
distCoeffs, // computed distortion matrix
cv::Mat(), // optional rectification (none)
cv::Mat(), // camera matrix to generate undistorted
outputSize, // size of undistorted
CV_32FC1, // type of output map
map1, map2); // the x and y mapping functions
mustInitUndistort= false;
}
// Apply mapping functions
cv::remap(image, undistorted, map1, map2,
cv::INTER_LINEAR); // interpolation type
return undistorted;
}
// Set the calibration options
// 8radialCoeffEnabled should be true if 8 radial coefficients are required (5 is default)
// tangentialParamEnabled should be true if tangeantial distortion is present
void CameraCalibrator::setCalibrationFlag(bool radial8CoeffEnabled, bool tangentialParamEnabled) {
// Set the flag used in cv::calibrateCamera()
flag = 0;
if (!tangentialParamEnabled) flag += CV_CALIB_ZERO_TANGENT_DIST;
if (radial8CoeffEnabled) flag += CV_CALIB_RATIONAL_MODEL;
}
#include <iostream>
#include <iomanip>
#include <vector>
#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/features2d.hpp>
#include "CameraCalibrator.h"
#define PATH "F:/QtProjects/stero/stereo4/right"
#define PICS_NUM 17
int main()
{
cv::Mat image;
std::vector<std::string> filelist;
// generate list of chessboard image filename
// named chessboard01 to chessboard27 in chessboard sub-dir
for (int i=1; i<=PICS_NUM; i++) {
std::stringstream str;
str << PATH << std::setw(2) << std::setfill('0') << i << ".png";
std::cout << str.str() << std::endl;
filelist.push_back(str.str());
image= cv::imread(str.str(),0);
// cv::imshow("Board Image",image);
// cv::waitKey(500);
}
// Create calibrator object
CameraCalibrator cameraCalibrator;
// add the corners from the chessboard
cv::Size boardSize(8,6);
cameraCalibrator.addChessboardPoints(
filelist, // filenames of chessboard image
boardSize, "Detected points"); // size of chessboard
// calibrate the camera
cameraCalibrator.setCalibrationFlag(true,true);
cameraCalibrator.calibrate(image.size());
// Exampple of Image Undistortion
std::cout << filelist[5] << std::endl;
image = cv::imread(filelist[5],0);
cv::Size newSize(static_cast<int>(image.cols*1.5), static_cast<int>(image.rows*1.5));
cv::Mat uImage= cameraCalibrator.remap(image, newSize);
// display camera matrix
cv::Mat cameraMatrix= cameraCalibrator.getCameraMatrix();
cv::Mat distCoeffs=cameraCalibrator.getDistCoeffs();
std::cout << " Camera intrinsic: " << cameraMatrix.rows << "x" << cameraMatrix.cols << std::endl;
std::cout << cameraMatrix.at<double>(0,0) << " " << cameraMatrix.at<double>(0,1) << " " << cameraMatrix.at<double>(0,2) << std::endl;
std::cout << cameraMatrix.at<double>(1,0) << " " << cameraMatrix.at<double>(1,1) << " " << cameraMatrix.at<double>(1,2) << std::endl;
std::cout << cameraMatrix.at<double>(2,0) << " " << cameraMatrix.at<double>(2,1) << " " << cameraMatrix.at<double>(2,2) << std::endl;
std::cout << distCoeffs.rows << "x" <<distCoeffs.cols << std::endl;
std::cout << distCoeffs << std::endl;
for(int i = 0;i < distCoeffs.cols;i++)
{
std::cout << distCoeffs.at<double>(0,i) << " " ;
}
std::cout <<std::endl;
cv::namedWindow("Original Image");
cv::imshow("Original Image", image);
cv::namedWindow("Undistorted Image");
cv::imshow("Undistorted Image", uImage);
// Store everything in a xml file
cv::FileStorage fs("calib.xml", cv::FileStorage::WRITE);
fs << "Intrinsic" << cameraMatrix;
fs << "Distortion" << cameraCalibrator.getDistCoeffs();
cv::waitKey();
return 0;
}
经验总结
- 照片要不同角度和距离拍摄,最好15张以上,不要偷懒。
- 出现矫正效果不好的情况,可以改变一下函数calibrateCamera中的参数flag。使用CV_CALIB_FIX_K3可以使畸变矩阵输出四个参数。根据网上博客的经验对于低端摄像头来说需要的参数数量一般使用5个或者4个比较合适。
From:OpenCV3.2 单目摄像头的标定与矫正 作者:Jacob杨帮帮