I tried your code and for me it works (it visualizes the current webcam input)! I ran it on Visual Studio 2012 Ultimate with OpenCV 2.4.7. … The error occurs because the image is empty, so try this: while (true) { cap >> image; if(!image.empty()){ imshow(“window”, image); } // delay 33ms waitKey(33); } Maybe the … Read more
First, I have to admit I agree with generic_opto_guy: The approach with the loop looks good, so we would need to check the math. On thing I noticed: if (oldRow > 0 && oldCol > 0 && oldRow <= oldHeight && oldCol <= oldWidth) implies you start indexing with 1. I belife that opencv starts … Read more
According to the code below, all callbacks would have to follow this definition: IplImage* custom_callback(IplImage* frame); This signature means the callback is going to be executed on each frame retrieved by the system. On my example, make_it_gray() allocates a new image to save the result of the grayscale conversion and returns it. This means you … Read more
The problem is with how OpenCV handles the initialization of the native library. Usually a class that uses a native library will have a static initializer that loads the library. This way the class and the native library will always be loaded in the same class loader. With OpenCV the application code loads the native … Read more
A lot of things changed from OpenCV 2.4 to OpenCV 3.0. Among others, the machine learning module, which isn’t backward compatible. This is the OpenCV tutorial code for the SVM, update for OpenCV 3.0: #include <opencv2/core.hpp> #include <opencv2/imgproc.hpp> #include “opencv2/imgcodecs.hpp” #include <opencv2/highgui.hpp> #include <opencv2/ml.hpp> using namespace cv; using namespace cv::ml; int main(int, char**) { // … Read more
Your second approach is correct, but you have source and destination of different types in cvtColor, and that causes the error. Be sure to have both hsv and bgr of the same type, CV_32F here: #include <opencv2/opencv.hpp> #include <iostream> int main() { cv::Mat3f hsv(cv::Vec3f(0.7, 0.7, 0.8)); std::cout << “HSV: ” << hsv << std::endl; cv::Mat3f … Read more
If you use OpenCV > 2.0 it is as easy as using namespace cv; Mat rotateImage(const Mat& source, double angle) { Point2f src_center(source.cols/2.0F, source.rows/2.0F); Mat rot_mat = getRotationMatrix2D(src_center, angle, 1.0); Mat dst; warpAffine(source, dst, rot_mat, source.size()); return dst; } Note: angle is in degrees, not radians. See the C++ interface documentation for more details and … Read more
As of OpenCV3.2, life just got a bit easier, you can now rotate an image in a single line of code: cv::rotate(image, image, cv::ROTATE_90_CLOCKWISE); For the direction you can choose any of the following: ROTATE_90_CLOCKWISE ROTATE_180 ROTATE_90_COUNTERCLOCKWISE
Update 29-5-2017: This also works with OpenCV 3.2.0-dev. Now using Visual Studio 2015 or 2017 gives no errors. The cv2.pyd is now automatically moved to site-packages. You just only need to copy the DLLs. As mentioned by @AleksandrUsarov in the comments section, this method still works for OpenCV 4.1.2, but you need to check OPENCV_ENABLE_NONFREE … Read more
I found the solution, lots of stuff was missing. I used the need-data signal like the examples of gst-rtsp-server. I changed some default parameters of appsrc, like the is-live, block and format. The caps on the appsrc element. I was not setting the offset of the buffer correctly. Here’s the code for anyone who’s facing … Read more