Originally, I used the mnemonic from OpenCV online guides: Mat::Mat(Size size, int type, void* data, size_t step=AUTO_STEP) But I didn’t understand what the document meant by size_t step=AUTO_STEP. And this means that I can omit the step argument with which OpenCV will automatically choose AUTO_STEP I’ve tried and this works: A = Mat(2, 5, CV_32FC1, … Read more
Developing from Miki’s answer, In OpenCV 3 definition has moved to modules/core/include/opencv2/core/traits.hpp, where you can find: /** @brief A helper class for cv::DataType The class is specialized for each fundamental numerical data type supported by OpenCV. It provides DataDepth<T>::value constant. */ template<typename _Tp> class DataDepth { public: enum { value = DataType<_Tp>::depth, fmt = DataType<_Tp>::fmt … Read more
To extend Otsu’s thresholding method to multi-level thresholding the between class variance equation becomes: Please check out Deng-Yuan Huang, Ta-Wei Lin, Wu-Chih Hu, Automatic Multilevel Thresholding Based on Two-Stage Otsu’s Method with Cluster Determination by Valley Estimation, Int. Journal of Innovative Computing, 2011, 7:5631-5644 for more information. http://www.ijicic.org/ijicic-10-05033.pdf Here is my C# implementation of Otsu … Read more
There are a couple of options. The easiest way is probably to install locally in the way the OpenCV site recommends: git clone https://github.com/Itseez/opencv.git cd opencv/ mkdir build install cd build cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/path/to/opencv/install .. make install Then add the following to your WORKSPACE file: new_local_repository( name = “opencv”, path = “/path/to/opencv/install”, build_file … Read more
I solved this a while ago, apologies for the year delay. In the python OpenCV 2.1 I was using, and the newer version 3.0.0-dev, I have verified that to get the pose of the camera in the global frame you must: _, rVec, tVec = cv2.solvePnP(objectPoints, imagePoints, cameraMatrix, distCoeffs) Rt = cv2.Rodrigues(rvec) R = Rt.transpose() … Read more
All zero-valued pixels in the same connected component as the seed point of the mask are replaced by the value you specify. This value must be added to the flags parameter, left-shifted by 8 bits: uchar fillValue = 128; cv::floodFill(img, mask, seed, cv::Scalar(255) ,0, cv::Scalar(), cv::Scalar(), 4 | cv::FLOODFILL_MASK_ONLY | (fillValue << 8)); A simple, … Read more
Try by disabling pre-compiled headers, either from cmake-gui or using the command line parameter -DENABLE_PRECOMPILED_HEADERS=OFF
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
I had the same issue on Windows 7 64-bit. I had to recompile opencv_highgui changing the “Preprocesser Definitions” in the C/C++ panel of the properties page to include: HAVE_VIDEOINPUT HAVE_DSHOW Hope this helps
Another, simpler way, that will probably translate better into OpenCV as it uses convolution rather than sequential Perl/C code. Basically set all the black pixels to value 10, and all the white pixels to value 0, then convolve the image with the following 3×3 kernel: 1 1 1 1 10 1 1 1 1 Now, … Read more