I want my application to create a window that will show my camera feed. my code is correct in regards to a vanilla implementation,
#include <opencv2/highgui.hpp>
#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <iostream>
int main()
{
cv::VideoCapture cap(0);
const cv::String windowName = "helloThere";
cv::Mat frame;
while(1)
{
cap >> frame;
if(frame.empty()) // Check for invalid input
{
std::cout << "Could not open or find the frame" << std::endl;
return -1;
}
imshow(windowName, frame);
std::cout << frame << std::endl;
}
return 0;
}
but I think that, because I am launching from CLion, the window object isn't launching properly. I am able to log output from the frame, so my question is:
Does anyone know how to get a namedWindow to launch from a CLion runtime? sort of a newb question, but I think helpful for posterity. I haven't seen anything about this
Related
My problem is that I cannot read from file I tried with .mp4 and .mov using cpp code on windows with library opencv3.4.0. I tried to read from camera it is working.
What could be the reason ?
cv::VideoCapture cap("001.mp4");
// Check if camera opened successfully
if (!cap.isOpened()) {
std::cout << "Error opening video stream or file" << std::endl;
break; //==>hits here
}
/// while below code part works correctly
cv::VideoCapture cap(0);
// Check if camera opened successfully
if (!cap.isOpened()) {
std::cout << "Error opening video stream or file" << std::endl;
break;
}
Copy and try below code, if it doesnt work either. It is completely about your opencv installation or directory mistake.
#include <opencv2/core.hpp>
#include <opencv2/videoio.hpp>
#include <opencv2/highgui.hpp>
#include <iostream>
#include <stdio.h>
#include "opencv2/opencv.hpp"
#include <iostream>
using namespace std;
using namespace cv;
int main(){
VideoCapture cap("videoname.mp4");
if(!cap.isOpened()){
cout << "Error opening video stream or file" << endl;
return -1;
}
while(1){
Mat frame;
cap >> frame;
if (frame.empty())
break;
imshow( "Frame", frame );
char c=(char)waitKey(25);
if(c==27)
break;
}
cap.release();
destroyAllWindows();
return 0;
}
I have a question about saving a video with openCV in C++ (I'm using Linux Ubuntu).
I was trying to save a stream from open camera for some time. I finally succeeded, but now I have really not many ideas why the saved stream doesn't have the same duration as I was streaming from my camera. When I am streaming for 10 seconds it has only for example 2-3 seconds and looks like it is accelerated.
Does anybody have some clue what could be the problem? Something wrong in my code or maybe computing performance, maybe the system doesn't save every frame?
Thanks for your help.
My code:
#include <stdio.h>
#include <iostream> // for standard I/O
#include <string> // for strings
#include <opencv2/core.hpp> // Basic OpenCV structures (cv::Mat)
#include <opencv2/videoio.hpp> // Video write
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/opencv.hpp"
using namespace std;
using namespace cv;
int main(int argc, char** argv)
{
Mat capture;
VideoCapture cap(0);
if(!cap.isOpened())
{
cout<<"Cannot connect to camera"<<endl;
return -1;
}
namedWindow("Display",CV_WINDOW_AUTOSIZE);
double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH);
double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT);
Size frameSize(static_cast<int>(dWidth), static_cast<int>(dHeight));
VideoWriter oVideoWriter ("/home/Stream_video/cpp/Cam/out.avi", CV_FOURCC('P','I','M','1'), 20, frameSize,true);
if ( !oVideoWriter.isOpened() ) {
cout << "ERROR: Failed to write the video" << endl;
return -1;
}
while(true){
Mat frame;
bool bSuccess = cap.read(frame); // read a new frame from video
if (!bSuccess) {
cout << "ERROR: Cannot read a frame from video file" << endl;
break; //if not success, break loop
}
oVideoWriter.write(frame); //writer the frame into the file
imshow("Display", frame);
if (waitKey(10) == 27) {
cout << "esc key is pressed by user" << endl;
break;
}
}
}
I'm trying to get OpenCV to work with visual studio. After following the official OpenCV installation instructions down to the letter, I tried building a sample program. I got the error in the title. The odd part is that the namespace 'cv' works fine - there are no errors for the rest of the code. Here's the sample program I tried to build:
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
if (argc != 2)
{
cout << " Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], IMREAD_COLOR); // Read the file
if (image.empty()) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl;
return -1;
}
namedWindow("Display window", WINDOW_AUTOSIZE); // Create a window for display.
imshow("Display window", image); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
In addition, here's my list of additional dependencies that I put in the project properties:
opencv_calib3d320d.lib
opencv_core320d.lib
opencv_features2d320d.lib
opencv_flann320d.lib
opencv_highgui320d.lib
opencv_imgcodecs320d.lib
opencv_imgproc320d.lib
opencv_ml320d.lib
opencv_objdetect320d.lib
opencv_photo320d.lib
opencv_shape320d.lib
opencv_stitching320d.lib
opencv_superres320d.lib
opencv_ts320d.lib
opencv_video320d.lib
opencv_videoio320d.lib
opencv_videostab320d.lib
I badly need this work :( . It should be noted that I have quadruple-checked the instructions to make this work, so I don't think it has to do with the header files or something.
I am reading in an image sequence from a file using an OpenCV VidoeCapture - I believe I am doing this part correctly - and then putting them in a c++ vector, for processing at a later point.
To test this, I wrote the following that would read in images, put them in a vector, and then display those images from the vector one by one. However, when I run this, no images appear.
What's wrong?
I am using a raspberry pi, I don't know if that makes any difference.
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <vector>
#include <iostream>
using namespace cv;
using namespace std;
vector<Mat> imageQueue;
int main(int argc, char** argv)
{
string arg = ("/home/pi/pictures/ceilingSequence/%02d.jpg");
VidoeCapture sequence(arg);
if(!sequence.isOpened()) {
cout << "Failed to open image sequence" << endl;
return -1;
}
Mat image;
for(;;)
{
sequence >> image;
if(image.empty()) {
cout << "End of sequence" << endl;
break;
}
imageQueue.push_back(image);
}
for(int i = 0; i < 10; i++)
{
//display 10 images
Mat readImage;
readImage = imageQueue[i];
namedWindow("Current Image", CV_WINDOW_AUTOSIZE);
imshow("Current Image", readImage);
sleep(2);
}
return 0;
}
please replace the sleep(2) with a waitKey(2000). // assuming you want to wait for 2 seconds
even if you're not interested in keypresses in general, it is needed to update the opencv / highgui graphics loop correctly.
I am using OpenCV 2.4.9 in Visual Studio 2010 and am trying to run simple source code provided on a tutorial website:
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main( int argc, char** argv )
{
if( argc != 2)
{
cout <<" Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
cout << argv[1] << std::endl;
return -1;
}
namedWindow( "Display window", WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
However, when I try to run the executable (and comment out that if statement) I get: Assertion failed (size.width>0 && size.height>0) in cv::imshow ......(file path)
I have looked at just about every related thread I have found on here. The file path is not wrong, I have printed it out and even moved the executable and jpg to the same folder.
Furthermore, this sample code from another tutorial does the exact same thing flawlessly, so I doubt it's a project configuration error but not sure:
#include <opencv2/opencv.hpp>
using namespace cv;
int main()
{
IplImage *img = cvLoadImage("C:\\Users\\bomoon\\Documents\\Koala.jpg", 1);
cvNamedWindow("test");
cvShowImage("test", img);
cvWaitKey(0);
cvReleaseImage(&img);
cvDestroyWindow("test");
return 0;
}
Can anyone explain why the second program works but not the first, and how I can fix the first one?
P.S.: It's not that I need to find a workaround to accomplish something, I'm trying to run sample code to verify the installation works, but it apparently doesn't if one sample program runs but not the other.