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@royshil
Last active May 8, 2024 05:49
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A simple video stabilizer in OpenCV, based on goodFeaturesToTrack, calcOpticalFlowPyrLK and estimateRigidTransform.
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/video/video.hpp>
#include <iostream>
using namespace cv;
using namespace std;
class Tracker {
vector<Point2f> trackedFeatures;
Mat prevGray;
public:
bool freshStart;
Mat_<float> rigidTransform;
Tracker():freshStart(true) {
rigidTransform = Mat::eye(3,3,CV_32FC1); //affine 2x3 in a 3x3 matrix
}
void processImage(Mat& img) {
Mat gray; cvtColor(img,gray,CV_BGR2GRAY);
vector<Point2f> corners;
if(trackedFeatures.size() < 200) {
goodFeaturesToTrack(gray,corners,300,0.01,10);
cout << "found " << corners.size() << " features\n";
for (int i = 0; i < corners.size(); ++i) {
trackedFeatures.push_back(corners[i]);
}
}
if(!prevGray.empty()) {
vector<uchar> status; vector<float> errors;
calcOpticalFlowPyrLK(prevGray,gray,trackedFeatures,corners,status,errors,Size(10,10));
if(countNonZero(status) < status.size() * 0.8) {
cout << "cataclysmic error \n";
rigidTransform = Mat::eye(3,3,CV_32FC1);
trackedFeatures.clear();
prevGray.release();
freshStart = true;
return;
} else
freshStart = false;
Mat_<float> newRigidTransform = estimateRigidTransform(trackedFeatures,corners,false);
Mat_<float> nrt33 = Mat_<float>::eye(3,3);
newRigidTransform.copyTo(nrt33.rowRange(0,2));
rigidTransform *= nrt33;
trackedFeatures.clear();
for (int i = 0; i < status.size(); ++i) {
if(status[i]) {
trackedFeatures.push_back(corners[i]);
}
}
}
for (int i = 0; i < trackedFeatures.size(); ++i) {
circle(img,trackedFeatures[i],3,Scalar(0,0,255),CV_FILLED);
}
gray.copyTo(prevGray);
}
};
int main() {
VideoCapture vc;
vc.open("myvideo.mp4");
Mat frame,orig,orig_warped,tmp;
Tracker tracker;
while(vc.isOpened()) {
vc >> frame;
if(frame.empty()) break;
frame.copyTo(orig);
tracker.processImage(orig);
Mat invTrans = tracker.rigidTransform.inv(DECOMP_SVD);
warpAffine(orig,orig_warped,invTrans.rowRange(0,2),Size());
imshow("orig",orig_warped);
int c = waitKey(0);
if(c == ' ') {
if(waitKey()==27) break;
} else
if(c == 27) break;
}
vc.release();
}
@martinfaucheux
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Hi !
Same question. I could open the video and display the interest points. Inside the window the black space constantly changes but it doesn't really stabilize my video. I use my phone cam as source with only small movement so according to the video you posted it should work. Any ideas ? Thanks

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