Measure OpenCV FPS
I have posted a way to do that @ Getting current FPS of OpenCV. It is necessary to do a bit of averaging otherwise the fps will be too jumpy.
edit
I have put a Sleep inside process() and it gives correct fps and duration(+/- 1ms).
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <opencv/cv.h>
#include <sys/timeb.h>
using namespace cv;
#if defined(_MSC_VER) || defined(WIN32) || defined(_WIN32) || defined(__WIN32__) \
|| defined(WIN64) || defined(_WIN64) || defined(__WIN64__)
#include <windows.h>
bool _qpcInited=false;
double PCFreq = 0.0;
__int64 CounterStart = 0;
void InitCounter()
{
LARGE_INTEGER li;
if(!QueryPerformanceFrequency(&li))
{
std::cout << "QueryPerformanceFrequency failed!\n";
}
PCFreq = double(li.QuadPart)/1000.0f;
_qpcInited=true;
}
double CLOCK()
{
if(!_qpcInited) InitCounter();
LARGE_INTEGER li;
QueryPerformanceCounter(&li);
return double(li.QuadPart)/PCFreq;
}
#endif
#if defined(unix) || defined(__unix) || defined(__unix__) \
|| defined(linux) || defined(__linux) || defined(__linux__) \
|| defined(sun) || defined(__sun) \
|| defined(BSD) || defined(__OpenBSD__) || defined(__NetBSD__) \
|| defined(__FreeBSD__) || defined __DragonFly__ \
|| defined(sgi) || defined(__sgi) \
|| defined(__MACOSX__) || defined(__APPLE__) \
|| defined(__CYGWIN__)
double CLOCK()
{
struct timespec t;
clock_gettime(CLOCK_MONOTONIC, &t);
return (t.tv_sec * 1000)+(t.tv_nsec*1e-6);
}
#endif
double _avgdur=0;
double _fpsstart=0;
double _avgfps=0;
double _fps1sec=0;
double avgdur(double newdur)
{
_avgdur=0.98*_avgdur+0.02*newdur;
return _avgdur;
}
double avgfps()
{
if(CLOCK()-_fpsstart>1000)
{
_fpsstart=CLOCK();
_avgfps=0.7*_avgfps+0.3*_fps1sec;
_fps1sec=0;
}
_fps1sec++;
return _avgfps;
}
void process(Mat& frame)
{
Sleep(3);
}
int main(int argc, char** argv)
{
int frameno=0;
cv::Mat frame;
cv::VideoCapture cap(0);
for(;;)
{
//cap>>frame;
double start=CLOCK();
process(frame);
double dur = CLOCK()-start;
printf("avg time per frame %f ms. fps %f. frameno = %d\n",avgdur(dur),avgfps(),frameno++ );
if(waitKey(1)==27)
exit(0);
}
return 0;
}
You can use OpenCV's API to get the original FPS if you are dealing with video files. The following method will not work when capturing from a live stream:
cv::VideoCapture capture("C:\\video.avi");
if (!capture.isOpened())
{
std::cout << "!!! Could not open input video" << std::endl;
return;
}
std::cout << "FPS: " << capture.get(CV_CAP_PROP_FPS) << std::endl;
To get the actual FPS after the processing, you can try Zaw's method.
You can use opencv helper cv::getTickCount()
#include <iostream>
#include <string>
#include "opencv2/core.hpp"
#include "opencv2/core/utility.hpp"
#include "opencv2/video.hpp"
#include "opencv2/highgui.hpp"
using namespace cv;
int main(int ac, char** av) {
VideoCapture capture(0);
Mat frame;
for (;;) {
int64 start = cv::getTickCount();
capture >> frame;
if (frame.empty())
break;
/* do some image processing here */
char key = (char)waitKey(1);
double fps = cv::getTickFrequency() / (cv::getTickCount() - start);
std::cout << "FPS : " << fps << std::endl;
}
return 0;
}