注：转载请标明原文出处链接：https://xiongyiming.blog.csdn.net/article/details/106937362

1 读取图像

#include <opencv2/core/core.hpp> 
#include <opencv2/imgcodecs.hpp> 
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/highgui/highgui_c.h>#include <iostream>
#include <math.h>using namespace cv;
using namespace std;
int main(int argc, char** args) {Mat src = imread("ZXP1.jpg", IMREAD_UNCHANGED);if (src.empty()) {cout << "could not find the image resource..." << std::endl;return -1;}namedWindow("Original Image", CV_WINDOW_AUTOSIZE);imshow("Original Image", src);waitKey(0);return 0;
}

运行结果

2 保存图像

#include <opencv2/core/core.hpp> 
#include <opencv2/imgcodecs.hpp> 
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/highgui/highgui_c.h>#include <iostream>
#include <math.h>using namespace cv;
using namespace std;
int main(int argc, char** args) {Mat src = imread("ZXP1.jpg", IMREAD_UNCHANGED);if (src.empty()) {cout << "could not find the image resource..." << std::endl;return -1;}namedWindow("Original Image", CV_WINDOW_AUTOSIZE);imshow("Original Image", src);Mat dst;cvtColor(src, dst, CV_BGR2GRAY);imwrite("ZXP_gray.png", dst);namedWindow("Output Image", CV_WINDOW_AUTOSIZE);imshow("Output Image", dst);waitKey(0);return 0;
}

运行结果

3 修改灰度图像的像素值

#include <opencv2/core/core.hpp> 
#include <opencv2/imgcodecs.hpp> 
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/highgui/highgui_c.h>#include <iostream>
#include <math.h>using namespace cv;
using namespace std;
int main(int argc, char** args) {Mat src = imread("ZXP1.jpg", IMREAD_UNCHANGED);if (src.empty()) {cout << "could not find the image resource..." << std::endl;return -1;}namedWindow("Original Image", CV_WINDOW_AUTOSIZE);imshow("Original Image", src);Mat gray_src;cvtColor(src, gray_src, CV_BGR2GRAY);namedWindow("Output Image_1", CV_WINDOW_AUTOSIZE);imshow("Output Image_1", gray_src);int height = gray_src.rows;int width = gray_src.cols;for (int row = 0; row < height; row++){for (int col = 0; col < width; col++){int gray_value = gray_src.at<uchar>(row, col);gray_src.at<uchar>(row, col) = 255 - gray_value;//修改像素值}}namedWindow("Output Image_2", CV_WINDOW_AUTOSIZE);imshow("Output Image_2", gray_src);waitKey(0);return 0;
}

运行结果

4 修改彩色图像的像素值

#include <opencv2/core/core.hpp> 
#include <opencv2/imgcodecs.hpp> 
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/highgui/highgui_c.h>#include <iostream>
#include <math.h>using namespace cv;
using namespace std;
int main(int argc, char** args) {Mat src = imread("ZXP1.jpg", IMREAD_UNCHANGED);if (src.empty()) {cout << "could not find the image resource..." << std::endl;return -1;}namedWindow("Original Image", CV_WINDOW_AUTOSIZE);imshow("Original Image", src);Mat gray_src;cvtColor(src, gray_src, CV_BGR2GRAY);namedWindow("Output Image_1", CV_WINDOW_AUTOSIZE);imshow("Output Image_1", gray_src);int height = gray_src.rows;int width = gray_src.cols;for (int row = 0; row < height; row++){for (int col = 0; col < width; col++){int gray_value = gray_src.at<uchar>(row, col);gray_src.at<uchar>(row, col) = 255 - gray_value;//修改像素值}}namedWindow("Output Image_2", CV_WINDOW_AUTOSIZE);imshow("Output Image_2", gray_src);int n = src.channels();Mat dst;dst.create(src.size(), src.type());//或者用dst = Mat(src.size(), src.type());for (int row = 0; row < height; row++){for (int col = 0; col < width; col++){int b = src.at<Vec3b>(row, col)[0];int g = src.at<Vec3b>(row, col)[1];int r = src.at<Vec3b>(row, col)[2];dst.at<Vec3b>(row, col)[0] = 255 - b ;dst.at<Vec3b>(row, col)[1] = 255 - g ;dst.at<Vec3b>(row, col)[2] = 255 - r ;}}namedWindow("Output Image_3", CV_WINDOW_AUTOSIZE);imshow("Output Image_3", dst);cout << src.type() << endl;cout << gray_src.type() << endl;cout << dst.type() << endl;waitKey(0);return 0;
}

运行结果

Vec3b 与 Vec3f 比较

1. Vec3b 对应三通道的顺序是Blue、Green、Red 的uchar类型数据；
2. Vec3f 对应三通道的float类型数据；
3. CV_8UC1 转换到 CV32F1 实现方法为：src.convertTo(dst, CV_32F);

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参考资料

[1] https://edu.51cto.com/course/7521.html?source=so