opencv中的getTickCount和getTickFrequency计算时间

首先上代码

比较两种计算时间方法：

GetTickcount函数：它返回从操作系统启动到当前所经的计时周期数。

getTickFrequency函数：返回每秒的计时周期数。

#include <iostream>
#include <string>
#include <fstream>
#include <omp.h>  //开启多核cpu计算模式
#include <cv.h>

using namespace std;
using namespace cv;

int main()
{

	double t1=(double)getTickCount();
	cout<<"t1 ="<<t1<<endl;
	int sum=0;
	for(int i=0;i<10000;i++)
	{
		sum+=i;
	}
	double t2=(double)getTickCount();
	cout<<"t2 ="<<t2<<endl;
	double time = (t2-t1)/getTickFrequency();
	cout<<"Time = "<<time<<endl;

	int64 e1 = getTickCount();
	cout<<"e1 ="<<e1<<endl;
    int sum1=0;
	for(int i=0;i<10000;i++)
	{
		sum1+=i;
	}
	int64 e2 = getTickCount();
	cout<<"e2 ="<<e2<<endl;
	double time1 = (e2-e1)/getTickFrequency();
	cout<<"time1 ="<<time1<<endl;

	system("pause");
	return 0;
}

代码结果：