"A calibration is required prior to running the activity" mean?

[janardhan1212]

Hi, thanks for sharing this project. how to run this calibration?

[jsmith613]

There is an activity Here. Just run the activity once on your device and you'll be set to go.

[janardhan1212]

I didn't find XML files for this activity and why should i run this activity?

[AdamMc331]

I can't find these XML files either. Any luck @janardhan1212 @jsmith613 ?

[jsmith613]

Sorry, been busy with schoolwork recently. So basically, lots of openCV and aruco methods require camera parameters as an input. To get those camera parameters, you need to run a calibration activity. You only need to run this once for a device and the parameters can be saved on your device. I believe I posted the wrong calibration activity on here. I'll take a look and see if I can get it working.

[oradomskyi]

Hi all =)
Rough and extremely fast solution - instead of loading camera parameters from file, create CameraParameters with some generic hardcoded data...

1. Add below code to CameraParameters class
   /* -------------- ADD TO CameraParameters -----------*/
   public void loadConstandCalibration()
   {
   cameraMatrix.put(0,0, 100000, 0.0, 960,
   0.0, 100000, 540,
   0.00000, 0.00000, 1.00000
   );

    double[] distArray =  {	0.0,
    						0.0,
    						0.0,
    						0.0,
    						0.0
    };
    distorsionMatrix.fromArray(distArray);
   

   }
   /* ----------------------------------------------------------*/
   Here is
   fx fy - focal length; fx=100000, fy=100000
   cx cy - camera center in pixels(my camera 1920x1080) cx=960 cy=540
   works pretty well on Note 4

2. Force MarkerTracker to load hardcpded data instead of loading file
   a) find and comment this line:
   camParams.readFromFile(Environment.getExternalStorageDirectory().toString() + DATA_FILEPATH);
   ...it becomes:
   //camParams.readFromFile(Environment.getExternalStorageDirectory().toString() + DATA_FILEPATH);

b) next to connemted line add this code:
camParams.loadConstandCalibration();
...it becomes
//camParams.readFromFile(Environment.getExternalStorageDirectory().toString() + DATA_FILEPATH);
camParams.loadConstandCalibration();

3. Trick detector. After some debugging i found that there is normal marker tracking but some fails when adding new markers... so let's go
   a) Find this section of code in MarkerDetector
   ...
   int id = marker.calculateMarkerId();
   if(id != -1){
   // rotate the points of the marker so they are always in the same order no matter the camera orientation
   Collections.rotate(marker.toList(), 4-marker.getRotations());
   newMarkers.add(marker);
   }
   ...

b) Move line "newMarkers.add(marker);" outside the IF statement
...
int id = marker.calculateMarkerId();
if(id != -1){
// rotate the points of the marker so they are always in the same order no matter the camera orientation
Collections.rotate(marker.toList(), 4-marker.getRotations());
newMarkers.add(marker); // inside the IF statement
}
newMarkers.add(marker); // outside the IF statement
...

Now all the stuff should work...
Enjoy =)

[pietjanssen]

Hey. I am trying to get this library to work on Android Studio 3.0. I am still having trouble with trying to run the camera calibration.

Can someone explain to me what I am supposed to do in order to run the camera calibration? Should I change anything in the AndroidManifest.xml in openCVTutorial1CameraPreview?

I tried the FrayaMiner's approach, and it works, but it makes the camera look distorted in color.