cvMinAreaRect2 for a list of Points: (-5:Bad argument) Exception

[Oleksandr]

Hello,

while been able to estimate the rectangle for an array (or a list) or points by using opencv-java as:

MatOfPoint2f mat = new MatOfPoint2f(pointList.toArray(new Point[] {}));
org.opencv.core.RotatedRect rrect = Imgproc.minAreaRect(mat);

I have problems to implement the same with javacv and getting

(-5:Bad argument) Unknown array type in function 'cvarrToMat'

E.g.

CvSeq seq = new CvSeq(cvPointsList.size());

for (int i = 0; i < cvPointsList.size(); i++) {
      seq.position(i).put(cvPointsList.get(i));
}

RotatedRect box = cvMinAreaRect2(seq).asRotatedRect(); <--- throws (-5:Bad argument) Unknown array type in function 'cvarrToMat'

Can you provide an example how to do that with javacv?

Many thanks in advance

Oleksandr

[Samuel Audet]

The C API of OpenCV is deprecated. If you don't have any legacy code to maintain,

I would recommend using the C++ API, probably something this (although I didn't test it):

    RotatedRect rr = minAreaRect(new Mat(pointList))

Samuel

[Oleksandr]

Thank you Samuel.

My problem is the mix of javacv and opencv-java code. If I understood it correctly ImgProc.minAreaRect is the Java port of C++ OpenCV = opencv-java (from comments in the source code). And I was wondering if I can get rid of opencv-java minAreaRect (as its result is also a opencv-java object), by evoking cvMinAreaRect2 or something else with the same functionality which returns a min area for 2D points.

Oleksandr

[Samuel Audet]

You can keep using the official Java API of OpenCV with JavaCV as well, there's no issues with that:

http://bytedeco.org/javacpp-presets/opencv/apidocs/org/opencv/imgproc/Imgproc.html#minAreaRect-org.opencv.core.MatOfPoint2f-

[Oleksandr]

Ok, thank you, Samuel.