OpenCV3讀取、寫入和保存圖像

需要說明的是在OpenCV3中已經將imread()和imwrite()函數轉移到imgcodecs模塊中，因此讀寫圖像時，需要包含imgcodecs.hpp頭文件，但是highgui.hpp頭文件中已經包含了該頭文件，因此不用再顯式包含了。

#include <iostream>
#include <string>
using namespace std;

// OpenCV includes
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
using namespace cv;

int main(int argc, const char** argv)
{
    // Read images
    Mat color = imread("../images/eating.jpg");
    Mat gray  = imread("../images/eating.jpg", 0);

    // Write images
    imwrite("gray.jpg", gray);

    // Get same pixel with opencv function
    int myRow = color.cols - 1;
    int myCol = color.rows - 1;
    Vec3b pixel = color.at<Vec3b>(myRow, myCol);
    cout << "Pixel Value (B, G, R): ("
         << (int)pixel[0] << ", "
         << (int)pixel[1] << ", "
         << (int)pixel[2] << ")" << endl;

    // Show images
    imshow("Color Image", color);
    imshow("Gray Image", gray);

    // Wait for any key
    waitKey(0);
    return 0;
}

 

顯示的圖片效果如下：