c++和opencv小知识：计算代码块执行时间

opencv工具函数getTickCount()

#include<opencv2/opencv.hpp>
#include<iostream>
using namespace std;
using namespace cv;
int main()
{
	//opencv实现时间的统计
	double time0 = static_cast<double>(getTickCount());
	//
	//放入要统计时间的程序
	//
	time0 = ((double)getTickCount() - time0) / getTickFrequency();
	cout << "计算时间：" << time0 << endl;
	waitKey(0);
	return 0;
}

c++< time.h >方式

clock_t start,end;
start = clock();
//需要测试运行时间的程序段
end = clock();

c++11中< chrono >统计代码块时间

#include <chrono>

auto start = chrono::steady_clock::now();

for (int i = 0; i < 1024; ++i) {
	cout << "hello C++11 !" << endl;
}

auto end = chrono::steady_clock::now();
chrono::duration<double, micro> elapsed = end - start; // stmicro 表示以微秒为时间单位
cout<< "time: "  << elapsed.count() << "us" << std::endl;