opencv通过三种方式访问Mat类型的数据

#include<opencv2/opencv.hpp>
#include<iostream>
#include<vector>

using namespace std;
using namespace cv;

void colorReduce(Mat&srcImage, Mat&dstImage, int div);

int main(int argc, char**argv)
{
	Mat srcImage = imread("D:/pic/pic_fgo.jpeg");
	Mat dstImage;
	double time0 = static_cast<double>(getTickCount());
	colorReduce(srcImage, dstImage, 32);
	time0 = ((double)getTickCount() - time0) / getTickFrequency();
	imshow("效果图", dstImage);
	waitKey(0);
}

void colorReduce(Mat&srcImage, Mat&dstImage, int div)
{
	dstImage = srcImage.clone();
	int rowNumber = dstImage.rows;
	int colNumber = dstImage.cols*dstImage.channels();
	for (int i = 0; i < rowNumber; i++)
	{
		uchar*data = dstImage.ptr<uchar>(i);
		for (int j = 0; j < colNumber; j++)
		{
			data[j] = data[j] / div * div + div / 2;
		}
	}
}

void colorReduce(Mat&srcImage, Mat&dstImage, int div)
{
	dstImage = srcImage.clone();
	Mat_<Vec3b>::iterator it = dstImage.begin<Vec3b>();
	Mat_<Vec3b>::iterator itend = dstImage.end<Vec3b>();
	for (; it != itend; it++)
	{
		(*it)[0] = (*it)[0] / div * div + div / 2;
		(*it)[1] = (*it)[1] / div * div + div / 2;
		(*it)[2] = (*it)[2] / div * div + div / 2;
	}
}

void colorReduce(Mat&srcImage, Mat&dstImage, int div)
{
	dstImage = srcImage.clone();
	int rowNumber = srcImage.rows;
	int colNumber = srcImage.cols;
	for(int i=0;i<rowNumber;i++)
		for (int j = 0; j < colNumber; j++)
		{
			dstImage.at<Vec3b>(i, j)[0] = srcImage.at<Vec3b>(i, j)[0] / div * div + div / 2;
			dstImage.at<Vec3b>(i, j)[1] = srcImage.at<Vec3b>(i, j)[1]/ div * div + div / 2;
			dstImage.at<Vec3b>(i, j)[2] = dstImage.at<Vec3b>(i, j)[2] / div * div + div / 2;
		}
}

标签：srcImage,Mat,dstImage,colorReduce,opencv,int,三种,div
来源： https://blog.csdn.net/qq_43036419/article/details/112685577