CODEWITHSUNDEEP
c++opencvc++11opencv3.0aruco
Bierbarbar
Bierbarbar

Reputation: 1479

OpenCv Aruco marker is not detected when i parse the Mat directly

Hope you can help me out. I try to use Aruco marker for finding the corners of an Window. So added an marker to each corner. But when i tried to detected the marker they don't get found. If it take a photo with an smartphone and then try to detect the marker on the Photo it works. Here is a minimum working Code example:

#include <opencv2/opencv.hpp>
#include <stdlib.h>
#include <string> 
#include <opencv2/aruco.hpp>
using namespace cv;
using namespace std;
using namespace aruco;

Dictionary dictionary;
int markerSize = 200;
vector<int> ids;
vector< vector<Point2f> > corners;


Mat addMarkertoImage(const Mat image){
    Mat retImage, marker0;
    image.copyTo(retImage);
    drawMarker(dictionary, 0, markerSize, marker0, 1);

    unsigned char value;

    //Add marker to top left corner
    for(int i = 0; i<marker0.rows; i++)
      for(int j = 0; j<marker0.cols; j++){
        value = marker0.at<uchar>(i,j);
        Vec3b colorValue = Vec3b(value, value, value);
        retImage.at<Vec3b>(i,j) = colorValue;} 
 return retImage;
 }


int main(){
        Mat image, image_marker;
dictionary = getPredefinedDictionary(cv::aruco::DICT_6X6_250); 
image = imread( "bild.jpg", 1 );
image_marker = addMarkertoImage(image);
detectMarkers(image_marker, dictionary, corners, ids);
drawDetectedMarkers(image_marker, corners, ids);
    imshow("Display Image", image_marker);
  waitKey(0);
  return 0;
}

Any Ideas, why this does not work? But with an Photo taken by my iPhone camera is working?

Upvotes: 0

Views: 3421

Answers (1)

Bierbarbar
Bierbarbar

Reputation: 1479

You meanwhile i solved the Problem on my own, the problem was the marker were to big to detected, with the default configuration. So i needed only to update the dectorparamenters and the example in the question worked.

Edit: Because i was asked of the changed parameters here. I added this code snipped with the changes:

ImageFinder::ImageFinder() {
    //initalize dictionary with markers....
    dictionary = getPredefinedDictionary(cv::aruco::DICT_6X6_250);
    dp = new DetectorParameters();
    dp->minDistanceToBorder = 0;
    dp->adaptiveThreshWinSizeMax = 400;
}

Upvotes: 1

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