mat

I have an app that prints a 3x3 cv::Mat on the iPhone screen. I need to reduce the decimals, as the screen is not so big, see: [1.004596557012473, -0.003116992336797859, 5.936915104939593; -0.007241746117066327, 0.9973985665720294, -0.2118670500989478; 1.477734234970711e-05, -1.03363734495053e-05, 1.000089074805124] so I would like to reduce the decimals .4 or .6 or six decimals. Any ideas? Cheers If you were using printf cv::Mat data(3, 3, CV_64FC1); for (int y = 0; y < data.rows; ++y) { for (int x = 0;x < data.cols; ++x) { printf("%.6f ", data.at<double>(y, x)); } } If you were using std:

I am developing an android application based on Tutorial 2 given by OpenCV4Android. What I want to achieve is to get the Mat object of the camera frame when I touch the phone's screen ( onTouch() ). I want to modify the code such that I store the image as Mat instead of a jpeg file on the phone's memory. The Mat will then go under further processing. Do I need to involve the onCameraFrame() function? Any guidance will be much appreciated. I am very new to Android developing and OpenCV as well. Note: I am using Android version 4.2.2 and OpenCV2.4.8. Edit: After editing onTouch() and

I just want to add the contents of 2 different Mat s to 1 other Mat . I tried: Mat1.copyTo(newMat); Mat2.copyTo(newMat); But that just seemed to overwrite the previous contents of the Mat . This may be a simple question, but I'm lost. It depends on what you want to add . For example, you have two 3x3 Mat: cv::Mat matA(3, 3, CV_8UC1, cv::Scalar(20)); cv::Mat matB(3, 3, CV_8UC1, cv::Scalar(80)); You can add matA and matB to a new 3x3 Mat with value 100 using matrix operation : auto matC = matA + matB; Or using array operation cv::add that does the same job: cv::Mat matD; cv::add(matA, matB, matD

From my question, Can I determine the number of channels in cv::Mat Opencv I am using the same code, to find the laplacian of Gaussian of the image. The edges around the objects are well detected in the image. How can I access the single element value of the final output image, abs_dst_gray? I know I have to use the '.at' operator and I also found its datatype to be CV_8U. I tried the following cout<<abs_dst_gray.at<uchar>(10,10)<<endl; But I was not able to know wat value it holds there, using this method. How can I find that value? If I use int or long, I end up with garbage values. I have

In C++/opencv, how can I select a subset of a big Mat and copy them to create a new Mat? I know how to use copyto, colrange, rowrange, etc., but don't know to combine them together to develop a decent and efficient code. Thanks! fatihk You can use copyTo() for this purpose: //copy a sub matrix of X to Y with starting coodinate (startX,startY) // and dimension (cols,rows) cv::Mat tmp = X(cv::Rect(startX,startY,cols,rows)); cv::Mat Y; tmp.copyTo(Y); or directly: cv::Mat Y; X(cv::Rect(startX,startY,cols,rows)).copyTo(Y); 来源： https://stackoverflow.com/questions/17691079/select-a-subset-of-a-mat