How to find corners on a Image using OpenCv

First, check out /samples/c/squares.c in your OpenCV distribution. This example provides a square detector, and it should be a pretty good start on how to detect corner-like features. Then, take a look at OpenCV’s feature-oriented functions like cvCornerHarris() and cvGoodFeaturesToTrack(). The above methods can return many corner-like features – most will not be the “true … Read more

How to process images of a video, frame by frame, in video streaming using OpenCV and Python

After reading the documentation of VideoCapture. I figured out that you can tell VideoCapture, which frame to process next time we call VideoCapture.read() (or VideoCapture.grab()). The problem is that when you want to read() a frame which is not ready, the VideoCapture object stuck on that frame and never proceed. So you have to force … Read more

cv2.imshow() function is opening a window that always says not responding – python opencv

You missed one more line: cv2.waitKey(0) Then the window shows the image until you press any key on keyboard. Or you can pass as following: cv2.waitKey(1000) cv2.destroyAllWindows() Here, window shows image for 1000 ms, or 1 second. After that, the window would disappear itself. But in some cases, it won’t. So you can forcefully destroy … Read more

opencv how can I select a region of image irregularly with mouse event? c/c++ [closed]

I had a little attempt at this – it is probably not the cleanest code, but should give you some ideas. #include <opencv2/opencv.hpp> #include <iostream> using namespace std; using namespace cv; // Globals bool finished=false; Mat img,ROI; vector<Point> vertices; void CallBackFunc(int event,int x,int y,int flags,void* userdata) { if(event==EVENT_RBUTTONDOWN){ cout << “Right mouse button clicked at … Read more