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2020-04-13 13:03:07 -0600 | commented question | cv2.imshow() doesn't work when I remove cv2.watKey(0) after it cv2.waitKey(1) will have negligible impact and will do what you want |
2020-04-12 18:10:24 -0600 | edited question | Drawing checkerboard's reference frame does not yield correct results (solvePnp+projectPoints) OpenCV solvePnP does not yield correct results Greetings, I have followed the tutorial at https://docs.opencv.org/mast |
2020-04-12 15:55:25 -0600 | asked a question | Drawing checkerboard's reference frame does not yield correct results (solvePnp+projectPoints) OpenCV solvePnP does not yield correct results Greetings, I have followed the tutorial at https://docs.opencv.org/mast |
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2013-05-08 16:38:25 -0600 | asked a question | cv::VideoCapture works for webcams but not IP cameras It had to happen, I'm stuck in the last phase of my project, when I want to use my code which works like a charm on my webcam, on an IP camera. The URL works perfectly in my browser, but nothing comes out with OpenCV... Here is my code: And the compiler settings : I've tested opening a .avi file with the same code and it works... But a public IP camera URL like Thanks for your help, Regards, Mister Mystère |
2013-05-06 13:27:25 -0600 | commented answer | Delay voluntarily a live feed from a VideoCapture I have a buffer for each camera so that should be fine for this. Well I'd be glad to share a code that worked for me using simply cv::Mat::clone() but I'm not allowed to answer my own question before 2 days so I'll post later. In the meantime I'm still looking for an explanation for having and a solution for avoiding tuning the timer to the actual FPS of the camera... Because otherwise I get an increase in the desired lag by up to 50% (at 30 fps instead of 23fps with which I have 10%) ! |
2013-05-06 05:00:03 -0600 | commented answer | Delay voluntarily a live feed from a VideoCapture Merci de votre réponse ;) I'm particularly interested in the first solution since it's a very simple one (I have quite a tight schedule). So I would need to grab an image in my timerEvent (so once every 35ms), and in that very method, as soon as a counter reaches delay*fps start retrieving at each call ? (I can't compile here for now) One important issue is the size of the buffer. I'll be dealing with delays up to 2 seconds (hence 60 frames in VGA)... Is it limited somehow ? Edit: Hmm, sounds like this solution would not allow for 2 cameras without some extra work around it. I saw cv::Mat::clone(), seems to answer my question doesn't it? |
2013-05-06 03:49:27 -0600 | asked a question | Delay voluntarily a live feed from a VideoCapture Hi, I have a class Camera inheriting from cv::VideoCapture, which its core method is to convert a cv::Mat that I get from a live stream to a QImage : And an encapsulating class CameraDelayedView which calls this method and adds a delay : The first frame is delayed like I want, but from that moment on, the video is a normal live feed like I would get without the queue system. Apparently, the images are part of a buffer which is updated, so that when creating a QImage with image.data, the pointers point at a frame which will be updated afterward. I want to avoid that: keep a snapshot, store it. Do I have to copy each image.data myself to make it independant, or is there a more efficient way ? Please do not hesitate to tell me if the above can be more efficient as well. Thanks in advance. Regards, Mister Mystère |
2013-05-06 03:41:35 -0600 | commented answer | Control PTZ Thank you for your answer. I ended up sniffing the communication port with WireShark for HTTP requests in order to get what the commands were because I couldn't find any API for this camera. Works like a charm :) |
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2013-05-01 06:48:23 -0600 | asked a question | Control PTZ Hi, I will soon be using OpenCV for retrieving a live feed from my Wanscam, but I don't know how to control the pan and tilt functionalities (C++), which are yet vital to my project. I couldn't find it in OpenCV's doc. Is it really absent from the API ? If so, would you happen to know how I could achieve this please ? Thanks in advance. Regards, Mister Mystère |