mat | 易学教程

How do i get the size of a multi-dimensional cv::Mat? (Mat, or MatND)

阅读更多关于 How do i get the size of a multi-dimensional cv::Mat? (Mat, or MatND)

问题 I am creating a multi-dimensional MAT object, and would like to get the size of the object - e.g., const int sz[] = {10,10,9}; Mat temp(3,sz,CV_64F); std::cout << "temp.dims = " << temp.dims << " temp.size = " << temp.size() << " temp.channels = " << temp.channels() << std::endl; I believe the resulting MAT to be 10x10x9, and I'd like to confirm, but the COUT statement gives: temp.dims = 3 temp.size = [10 x 10] temp.channels = 1 I was hoping to see either: temp.dims = 3 temp.size = [10 x 10 x

How to capture the desktop in OpenCV (ie. turn a bitmap into a Mat)?

阅读更多关于 How to capture the desktop in OpenCV (ie. turn a bitmap into a Mat)?

I want to use OpenCV to process my desktop as if it were a video stream. I am familiar with OpenCV. I am not familiar with the Windows API. I realize there are other ways to capture the screen, but for the purposes of my question, I need it to be done using OpenCV. Here is my (super naive) code: HWND hDesktopWnd; HDC hDesktopDC; hDesktopWnd=GetDesktopWindow(); hDesktopDC=GetDC(hDesktopWnd); // get the height and width of the screen int height = GetSystemMetrics(SM_CYVIRTUALSCREEN); int width = GetSystemMetrics(SM_CXVIRTUALSCREEN); // create a bitmap HBITMAP hbDesktop = CreateCompatibleBitmap(

How to read a v7.3 mat file via h5py?

阅读更多关于 How to read a v7.3 mat file via h5py?

问题 I have a struct array created by matlab and stored in v7.3 format mat file: struArray = struct(\'name\', {\'one\', \'two\', \'three\'}, \'id\', {1,2,3}, \'data\', {[1:10], [3:9], [0]}) save(\'test.mat\', \'struArray\', \'-v7.3\') Now I want to read this file via python using h5py: data = h5py.File(\'test.mat\') struArray = data[\'/struArray\'] I have no idea how to get the struct data one by one from struArray : for index in range(<the size of struArray>): elem = <the index th struct in

cv::Mat to QImage and back

阅读更多关于 cv::Mat to QImage and back

问题 //Sorry for my english. Tell me please, what I am doing wrong? I have read a lot about this. And write some code, but I have a terrible result. As I understand in Opencv CV_8UC3 is the same as QImage::Format_RGB888 , except BRG and RGB accordingly. to read cv::Mat in this format I can do: cv::Mat mat1 = cv::imread(\"bugero.jpg\",3); So, to convert cv::Mat to QImage I can do: QImage Mat2QImage(cv::Mat const& src) { cv::Mat temp(src.cols,src.rows,src.type()); cvtColor(src, temp,CV_BGR2RGB);

Efficiently load a large Mat into memory in OpenCV

阅读更多关于 Efficiently load a large Mat into memory in OpenCV

Is there a more efficient way to load a large Mat object into memory than the FileStorage method in OpenCV? I have a large Mat with 192 columns and 1 million rows I want to store locally in a file and load into memory then my application starts. There is no problem using the FileStorage, but I was wondering if there exists a more efficient method to do this. At the moment it takes about 5 minutes to load the Mat into memory using the Debug mode in Visual Studio and around 3 minutes in the Release mode and the size of the data file is around 1.2GB. Is the FileStorage method the only method

How to capture the desktop in OpenCV (ie. turn a bitmap into a Mat)?

阅读更多关于 How to capture the desktop in OpenCV (ie. turn a bitmap into a Mat)?

问题 I want to use OpenCV to process my desktop as if it were a video stream. I am familiar with OpenCV. I am not familiar with the Windows API. I realize there are other ways to capture the screen, but for the purposes of my question, I need it to be done using OpenCV. Here is my (super naive) code: HWND hDesktopWnd; HDC hDesktopDC; hDesktopWnd=GetDesktopWindow(); hDesktopDC=GetDC(hDesktopWnd); // get the height and width of the screen int height = GetSystemMetrics(SM_CYVIRTUALSCREEN); int width