点运算

公式：

G(X)=a*raw(X)+b
线性方程，改变图像的亮度

#include<opencv2/opencv.hpp>
#include<iostream>
using namespace cv;
using namespace std;
int main() {
    Mat src;
    src = imread("F:/test.jpg");
    int width = src.cols;
    int height = src.rows;
    Mat dst;
    dst = Mat::zeros(src.size(), src.type());
    float alpha = 1.2;
    float beta = 30;
    Mat ml;
    src.convertTo(ml, CV_32F);
    for (int row = 0; row < height; row++) {
        for (int col = 0; col < width; col++) {
            if (src.channels() == 3) {
                float b = ml.at<Vec3f>(row, col)[0];
                float g = ml.at<Vec3f>(row, col)[1];
                float r = ml.at<Vec3f>(row, col)[2];

                dst.at<Vec3b>(row, col)[0] = saturate_cast<uchar>(b*alpha + beta);
                dst.at<Vec3b>(row, col)[1] = saturate_cast<uchar>(g*alpha + beta);
                dst.at<Vec3b>(row, col)[2] = saturate_cast<uchar>(r*alpha + beta);
            }
        }
    }
    
    imshow("点运算", dst);
    waitKey(0);
    return 0;
}