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#include <ctime>
#include <iostream>
#include <vector>
#include <opencv2/calib3d.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/objdetect/aruco_detector.hpp>
#include "aruco_samples_utility.hpp"
using namespace std;
using namespace cv;
namespace {
const char* about =
"Calibration using a ArUco Planar Grid board\n"
" To capture a frame for calibration, press 'c',\n"
" If input comes from video, press any key for next frame\n"
" To finish capturing, press 'ESC' key and calibration starts.\n";
const char* keys =
"{w | | Number of squares in X direction }"
"{h | | Number of squares in Y direction }"
"{l | | Marker side length (in meters) }"
"{s | | Separation between two consecutive markers in the grid (in meters) }"
"{d | | dictionary: DICT_4X4_50=0, DICT_4X4_100=1, DICT_4X4_250=2,"
"DICT_4X4_1000=3, DICT_5X5_50=4, DICT_5X5_100=5, DICT_5X5_250=6, DICT_5X5_1000=7, "
"DICT_6X6_50=8, DICT_6X6_100=9, DICT_6X6_250=10, DICT_6X6_1000=11, DICT_7X7_50=12,"
"DICT_7X7_100=13, DICT_7X7_250=14, DICT_7X7_1000=15, DICT_ARUCO_ORIGINAL = 16}"
"{cd | | Input file with custom dictionary }"
"{@outfile |cam.yml| Output file with calibrated camera parameters }"
"{v | | Input from video file, if ommited, input comes from camera }"
"{ci | 0 | Camera id if input doesnt come from video (-v) }"
"{dp | | File of marker detector parameters }"
"{rs | false | Apply refind strategy }"
"{zt | false | Assume zero tangential distortion }"
"{a | | Fix aspect ratio (fx/fy) to this value }"
"{pc | false | Fix the principal point at the center }";
}
int main(int argc, char *argv[]) {
CommandLineParser parser(argc, argv, keys);
parser.about(about);
if(argc < 6) {
parser.printMessage();
return 0;
}
int markersX = parser.get<int>("w");
int markersY = parser.get<int>("h");
float markerLength = parser.get<float>("l");
float markerSeparation = parser.get<float>("s");
string outputFile = parser.get<string>(0);
int calibrationFlags = 0;
float aspectRatio = 1;
if(parser.has("a")) {
calibrationFlags |= CALIB_FIX_ASPECT_RATIO;
aspectRatio = parser.get<float>("a");
}
if(parser.get<bool>("zt")) calibrationFlags |= CALIB_ZERO_TANGENT_DIST;
if(parser.get<bool>("pc")) calibrationFlags |= CALIB_FIX_PRINCIPAL_POINT;
aruco::Dictionary dictionary = readDictionatyFromCommandLine(parser);
aruco::DetectorParameters detectorParams = readDetectorParamsFromCommandLine(parser);
bool refindStrategy = parser.get<bool>("rs");
int camId = parser.get<int>("ci");
String video;
if(parser.has("v")) {
video = parser.get<String>("v");
}
if(!parser.check()) {
parser.printErrors();
return 0;
}
VideoCapture inputVideo;
int waitTime;
if(!video.empty()) {
inputVideo.open(video);
waitTime = 0;
} else {
inputVideo.open(camId);
waitTime = 10;
}
//! [CalibrationWithArucoBoard1]
// Create board object and ArucoDetector
aruco::GridBoard gridboard(Size(markersX, markersY), markerLength, markerSeparation, dictionary);
aruco::ArucoDetector detector(dictionary, detectorParams);
// Collected frames for calibration
vector<vector<vector<Point2f>>> allMarkerCorners;
vector<vector<int>> allMarkerIds;
Size imageSize;
while(inputVideo.grab()) {
Mat image, imageCopy;
inputVideo.retrieve(image);
vector<int> markerIds;
vector<vector<Point2f>> markerCorners, rejectedMarkers;
// Detect markers
detector.detectMarkers(image, markerCorners, markerIds, rejectedMarkers);
// Refind strategy to detect more markers
if(refindStrategy) {
detector.refineDetectedMarkers(image, gridboard, markerCorners, markerIds, rejectedMarkers);
}
//! [CalibrationWithArucoBoard1]
// Draw results
image.copyTo(imageCopy);
if(!markerIds.empty()) {
aruco::drawDetectedMarkers(imageCopy, markerCorners, markerIds);
}
putText(imageCopy, "Press 'c' to add current frame. 'ESC' to finish and calibrate",
Point(10, 20), FONT_HERSHEY_SIMPLEX, 0.5, Scalar(255, 0, 0), 2);
imshow("out", imageCopy);
// Wait for key pressed
char key = (char)waitKey(waitTime);
if(key == 27) {
break;
}
//! [CalibrationWithArucoBoard2]
if(key == 'c' && !markerIds.empty()) {
cout << "Frame captured" << endl;
allMarkerCorners.push_back(markerCorners);
allMarkerIds.push_back(markerIds);
imageSize = image.size();
}
}
//! [CalibrationWithArucoBoard2]
if(allMarkerIds.empty()) {
throw std::runtime_error("Not enough captures for calibration\n");
}
//! [CalibrationWithArucoBoard3]
Mat cameraMatrix, distCoeffs;
if(calibrationFlags & CALIB_FIX_ASPECT_RATIO) {
cameraMatrix = Mat::eye(3, 3, CV_64F);
cameraMatrix.at<double>(0, 0) = aspectRatio;
}
// Prepare data for calibration
vector<Point3f> objectPoints;
vector<Point2f> imagePoints;
vector<Mat> processedObjectPoints, processedImagePoints;
size_t nFrames = allMarkerCorners.size();
for(size_t frame = 0; frame < nFrames; frame++) {
Mat currentImgPoints, currentObjPoints;
gridboard.matchImagePoints(allMarkerCorners[frame], allMarkerIds[frame], currentObjPoints, currentImgPoints);
if(currentImgPoints.total() > 0 && currentObjPoints.total() > 0) {
processedImagePoints.push_back(currentImgPoints);
processedObjectPoints.push_back(currentObjPoints);
}
}
// Calibrate camera
double repError = calibrateCamera(processedObjectPoints, processedImagePoints, imageSize, cameraMatrix, distCoeffs,
noArray(), noArray(), noArray(), noArray(), noArray(), calibrationFlags);
//! [CalibrationWithArucoBoard3]
bool saveOk = saveCameraParams(outputFile, imageSize, aspectRatio, calibrationFlags,
cameraMatrix, distCoeffs, repError);
if(!saveOk) {
throw std::runtime_error("Cannot save output file\n");
}
cout << "Rep Error: " << repError << endl;
cout << "Calibration saved to " << outputFile << endl;
return 0;
}
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