I am trying to use OpenCV for Android (OpenCV 2.4.3) I am writing a program to track keypoints. I am trying to use FeatureDetector to detect keypoints and then Video.calcOpticalFlowPyrLK to track them. The question that has me stumped is that the FeatureDetector function returns a MatOfKeyPoint while calcOpticalFlowPyrLK takes a MatOfPoint2f.
Here is my code so far:
//Feature detector for LKT flow estimation
FeatureDetector cvFeatureDetector;
//Vector of keypoints
MatOfKeyPoint keypoints;
...
//intitialize detector
cvFeatureDetector = FeatureDetector.create(FeatureDetector.GFTT);
keypoints = new MatOfKeyPoint();
...
//mPrevImgMat is a grayscale image - previous frame
//mCurrentImgMat is a grayscale image - current frame
//Run feature detector in previous image
cvFeatureDetector.detect(mPrevImgMat, keypoints);
MatOfPoint2f keypointsFound = new MatOfPoint2f();
MatOfByte keypointsStatus = new MatOfByte();
MatOfFloat err = new MatOfFloat();
Size winSize = new Size(25,25);
int maxLevel = 3;
//Optical flow to find keypoints in current image
Video.calcOpticalFlowPyrLK(mPrevImgMat, mCurrentImgMat, keypoints,
keypointsFound, keypointsStatus, err, winSize, maxLevel);
//Obviously "keypoints" in the line above does not work. How does one covert
//keypoints to MatOfPoint2f?
Things I have tried unsuccessfully so far:
1. `keypoints.convertTo()`
2. Creating a vector from keypoints and then
trying to populate a vector of Point Vector pointList. Then typecast to
`MatOfPoint2f` when calling flow funciton (`MatOfPoint2f`) pointList
3. Trying to populate a `MatOfPoint2f` from scratch. Cant figure out how to
do this 4 Using `fromArray` method in `MatOfPoint2f` - Not sure what this
method does. Documentation is blank for this method. Am I missing
something obvious?
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