Aruco tutorial code does not compile

问题

Hello I am getting an error when using aruco. I am just trying to get an example from the tutorial working. I did everything according to the tutorial but I get:

    /home/pi/Programs/markerDetection/markerDetection.cpp: In function ‘int main(int, char**)’:
/home/pi/Programs/markerDetection/markerDetection.cpp:26:104: error: invalid initialization of reference of type ‘cv::Ptr<cv::aruco::Dictionary>&’ from expression of type ‘cv::aruco::Dictionary’
   aruco::detectMarkers(inputImage, dictionary, markerCorners, markerIds, parameters, rejectedCandidates);
                                                                                                        ^
In file included from /home/pi/Programs/markerDetection/markerDetection.cpp:6:0:
/home/pi/opencv/include/opencv2/aruco.hpp:176:19: note: in passing argument 2 of ‘void cv::aruco::detectMarkers(cv::InputArray, cv::Ptr<cv::aruco::Dictionary>&, cv::OutputArrayOfArrays, cv::OutputArray, const cv::Ptr<cv::aruco::DetectorParameters>&, cv::OutputArrayOfArrays)’
 CV_EXPORTS_W void detectMarkers(InputArray image, Ptr<Dictionary> &dictionary, OutputArrayOfArrays corners,
                   ^
CMakeFiles/marker.dir/build.make:54: recipe for target 'CMakeFiles/marker.dir/markerDetection.cpp.o' failed
make[2]: *** [CMakeFiles/marker.dir/markerDetection.cpp.o] Error 1
CMakeFiles/Makefile2:60: recipe for target 'CMakeFiles/marker.dir/all' failed
make[1]: *** [CMakeFiles/marker.dir/all] Error 2
Makefile:76: recipe for target 'all' failed
make: *** [all] Error 2

My code is:

#include "opencv2/opencv.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/videoio/videoio.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/aruco.hpp"
#include <vector>

using namespace cv;
using namespace std;

int main (int argc, char** argv)
{
        VideoCapture cap;

        if(!cap.open(0)){
                return 0;
        }
        for(;;){
                Mat inputImage;
                cap >> inputImage;
                vector< int > markerIds;
                vector< vector<Point2f> > markerCorners, rejectedCandidates;
                aruco::DetectorParameters parameters;
                aruco::Dictionary dictionary = aruco::getPredefinedDictionary(aruco::DICT_6X6_250);
                aruco::detectMarkers(inputImage, dictionary, markerCorners, markerIds, parameters, rejectedCandidates);
                Mat outputImage;
                aruco::drawDetectedMarkers(outputImage, markerCorners, markerIds);
                if(inputImage.empty()) break;
                imshow("Webcam", outputImage);
                if(waitKey(1) >= 0) break;
        }

        return 0;
}

I know there are too many includes and the code needs some work but I just need it to compile and I have no idea what is happening there. Has the function changed?

回答1:

The following code works for me:

Dictionary declaration:

cv::Ptr<cv::aruco::Dictionary> dictionary =   cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);

As the function getPredefinedDictionary returns a Ptr<Dictionary> (http://docs.opencv.org/trunk/d9/d6a/group__aruco.html)

To detect markers:

cv::aruco::detectMarkers(gray, dictionary, marker_corners, marker_ids);

回答2:

I had the same problem as you. Here is what did the trick:

instead of:

aruco::DetectorParameters parameters;
aruco::Dictionary dictionary=aruco::getPredefinedDictionary(aruco::DICT_6X6_250);

use:

cv::Ptr<aruco::DetectorParameters> parameters;
cv::Ptr<aruco::Dictionary> dictionary=aruco::getPredefinedDictionary(aruco::DICT_6X6_250);

I hope it helps you.

来源：https://stackoverflow.com/questions/36391657/aruco-tutorial-code-does-not-compile

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