opencv遍历图像方法集合

#include <opencv.hpp>
#include<iostream>
#include <string>
#include<conio.h>
#include<time.h>
#include<math.h>
using namespace cv;
using namespace std;
//测试时间
void PrintMs(const char* text = " ")
{
	static long long last = 0;
	long long cur = getTickCount();
	if (last == 0)
	{
		last = cur;
		return;
	}

	long long ms = 0;
	ms = ((double)(cur - last) / getTickFrequency()) * 1000;
	if (*text != 0)
	{
		printf("%s = %dms\n", text, ms);
	}

	last = getCPUTickCount();

}
int main()
{
	Mat m,m2;
	//创建指定大小的数组，数据类型为TYPE,
	m.create(100, 100, CV_8UC3);
	//构造指定数组，数据类型为TYPE,值全为0的数组
	m2 = Mat::zeros(1000, 1000, CV_8UC3);
	Point point(300, 300);
	circle(m2, point, 100, Scalar(0, 127, 127), 1, 8, 0);

	namedWindow("circle", 1);
	imshow("circle", m2);
	RNG rng;

	//多通道数组访问，通过模板函数at<>访问
	for (int i = 0; i < m2.rows; i++)
	{
		for (int j = 0; j < m2.cols; j++)
		{
			m2.at<Vec3b>(j, i)[0] = rng.uniform(0, 255);
			m2.at<Vec3b>(j, i)[1] = rng.uniform(0, 255);
			m2.at<Vec3b>(j, i)[2] = rng.uniform(0, 255);
		}

	}

	imshow("at<> mat", m2);
	PrintMs("at>mat");
		//直接地址访问连续空间
	for (int i = 0; i < m2.rows*m2.elemSize(); i++)
	{
		m2.data[i] = 0;			//B
		m2.data[i + 1] = 127;	//G
		m2.data[i + 2] = 0;		//R
	}

	imshow("lianxu di zhi kong jian", m2);

	PrintMs("直接地址访问连续空间");


	//直接地址访问不连续空间
	for (int i = 0; i < m2.rows; i++)
	{
		for (int j = 0; j < m2.cols; j++)
		{
			(&m2.data[i*m2.step])[j*3] = 255;			//B
			(&m2.data[i * m2.step])[j * 3+1] = 255;	//G
			(&m2.data[i * m2.step])[j * 3+2] = 1;		//R
		}
		
	}

	imshow("bu lianxu kong jian", m2);
	PrintMs("直接地址访问不连续空间");

	//通过ptr接口遍历Mat（模板函数）
	//性能基本等同有地址访问
	//mat.ptr<Vec3b>(row) 返回的指针
	//mat.ptr<Vec3b>(row,col);
	for (int i = 0; i < m2.rows; i++)
	{
		for (int j = 0; j < m2.cols; j++)
		{
			Vec3b *c= m2.ptr<Vec3b>(i, j);
			c->val[0] = 255;
			c->val[1] = 0;
			c->val[2] = 0;

		}

	}

	imshow("ptr *", m2);
	PrintMs("通过ptr接口遍历Mat（模板函数):");
	//try 捕获异常
	try{
	//使用at引用遍历
	for (int i = 0; i < m2.rows; i++)
	{
		for (int j = 0; j < m2.cols; j++)
		{
			Vec3b& c = m2.at<Vec3b>(i, j);
			c[0] = 100;
			c[1] = 100;
			c[2] = 100;
		}

	}

	}
	catch (Exception &ex)
	{
		cout << ex.what() << endl;//抛出一场
	}
	imshow("use at<> reference", m2);

	PrintMs("使用at引用遍历:");

	//使用迭代器遍历Mat
	//可以不用管Mat的行列
	auto it = m2.begin<Vec3b>();
	auto it_end = m2.end<Vec3b>();
	for (; it!=it_end; it++)
	{
		(*it).val[0] = 0;
		(*it).val[1] = 0;
		(*it).val[2] = 255;
	}
	imshow("use *it", m2);
	PrintMs("使用迭代器遍历Mat:");
	waitKey(0);

	return 0;
}