[opencv450] salt and pepper noise demo

Salt and pepper noise

Source code ：

#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
using namespace cv;
using namespace std;


// Salt and pepper noise function 
void saltAndPepper(Mat image, int n)
{
    int i = 0, j = 0, write_black = 0;
    for (int k = 0; k < n; ++k)
    {
        // Randomly determine the position in the image 




        i = rand() % image.cols;// Take the remainder operation , Ensure that within the number of columns of the image 
        j = rand() % image.rows;// Take the remainder operation , Ensure that within the number of lines of the image 
        write_black = 1;// rand() % 2;// A variable that determines whether it is white noise or black noise 
        if (write_black == 0)
        {// Add white noise 
            if (image.type() == CV_8UC1)
            {// Process grayscale images 
                image.at<uchar>(j, i) = 255;// White noise 
            }
            else if (image.type() == CV_8UC3) {// Process color images 
                image.at<Vec3b>(j, i)[0] = 255;//Vec3b by opencv Defined 3 Vector type of a value 
                image.at<Vec3b>(j, i)[1] = 255;//[] Establish access ,B:0,G:1,R:2
                image.at<Vec3b>(j, i)[2] = 255;
            }
        }
        else
        {// Add black noise 
            if (image.type() == CV_8UC1)
            {
                image.at<uchar>(j, i) = 0;
            }
            if (image.type() == CV_8UC3)
            {
                image.at<Vec3b>(j, i)[0] = 0;//Vec3b by opencv Defined 3 Vector type of a value 
                image.at<Vec3b>(j, i)[1] = 0;//[] Establish access ,B:0,G:1,R:2
                image.at<Vec3b>(j, i)[2] = 0;
            }




        }
    }
}


int main() {
    Mat img_ = imread(".\\5.jpg");
    Mat img;
    resize(img_, img, Size(img_.cols / 2, img_.rows / 2));
    Mat gray;
    cvtColor(img, gray, COLOR_BGR2GRAY);
    if (img.empty() || gray.empty()) {
        cout << " Please confirm whether the entered path is correct " << endl;
        return -1;
    }
    imshow("luffy Original picture ", img);
    imshow("luffy_gray Original picture ", gray);
    saltAndPepper(img, 1000);// Add salt and pepper noise to color images 
    saltAndPepper(gray, 1000);// Add salt and pepper noise to gray image 
    imshow("luffy Add noise ", img);
    imshow("luffy_gray Add noise ", gray);
    imwrite(".\\salt5.jpg", img);
    waitKey(0);
    destroyAllWindows();
    return 0;
}

Reference resources ：

https://blog.csdn.net/weixin_51326570/article/details/115184484