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Merge pull request #11723 from alalek:sample_videocapture_camera

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Alexander Alekhin 2018-06-09 13:49:20 +00:00
commit 93f2fd396b
1 changed files with 76 additions and 0 deletions
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samples/cpp/videocapture_camera.cpp Normal file
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#include <opencv2/core.hpp>
#include <opencv2/videoio.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp> // cv::Canny()
#include <iostream>
using namespace cv;
using std::cout; using std::cerr; using std::endl;
int main(int, char**)
{
Mat frame;
cout << "Opening camera..." << endl;
VideoCapture capture(-1); // open the first available camera
if (!capture.isOpened())
{
cerr << "ERROR: Can't initialize camera capture" << endl;
return 1;
}
cout << "Frame width: " << capture.get(CAP_PROP_FRAME_WIDTH) << endl;
cout << " height: " << capture.get(CAP_PROP_FRAME_HEIGHT) << endl;
cout << "Capturing FPS: " << capture.get(CAP_PROP_FPS) << endl;
cout << endl << "Press 'ESC' to quit, 'space' to toggle frame processing" << endl;
cout << endl << "Start grabbing..." << endl;
size_t nFrames = 0;
bool enableProcessing = false;
int64 t0 = cv::getTickCount();
int64 processingTime = 0;
for (;;)
{
capture >> frame; // read the next frame from camera
if (frame.empty())
{
cerr << "ERROR: Can't grab camera frame." << endl;
break;
}
nFrames++;
if (nFrames % 10 == 0)
{
const int N = 10;
int64 t1 = cv::getTickCount();
cout << "Frames captured: " << cv::format("%5lld", (long long int)nFrames)
<< " Average FPS: " << cv::format("%9.1f", (double)getTickFrequency() * N / (t1 - t0))
<< " Average time per frame: " << cv::format("%9.2f ms", (double)(t1 - t0) * 1000.0f / (N * getTickFrequency()))
<< " Average processing time: " << cv::format("%9.2f ms", (double)(processingTime) * 1000.0f / (N * getTickFrequency()))
<< std::endl;
t0 = t1;
processingTime = 0;
}
if (!enableProcessing)
{
imshow("Frame", frame);
}
else
{
int64 tp0 = cv::getTickCount();
Mat processed;
cv::Canny(frame, processed, 400, 1000, 5);
processingTime += cv::getTickCount() - tp0;
imshow("Frame", processed);
}
int key = waitKey(1);
if (key == 27/*ESC*/)
break;
if (key == 32/*SPACE*/)
{
enableProcessing = !enableProcessing;
cout << "Enable frame processing ('space' key): " << enableProcessing << endl;
}
}
std::cout << "Number of captured frames: " << nFrames << endl;
return nFrames > 0 ? 0 : 1;
}