How to convert MatOfPoint to MatOfPoint2f in opencv java api

Question

I\'m trying to implement the example code of the following question by using opencv java api. To implement findContours(gray, contours, CV_RETR_LIST, CV_CHAIN_APPROX_

Answer 1

Although this question has already been answered, I believe that the accepted answer is not the best. Converting a matrix to an array and then back comes with quite the performance penalty, both time-wise and memory-wise.

Instead, OpenCV already has a function that does exactly this: convertTo.

MatOfPoint src;
// initialize src
MatOfPoint2f dst = new MatOfPoint2f();
src.convertTo(dst, CvType.CV_32F);

I have found this to be significantly faster and more memory-friendly.

To convert a MatOfPoint2f to a MatOfPoint, use CvType.CV_32S instead.