图像的采样、DOG

#include <opencv2/opencv.hpp>
#include <iostream>
#include "math.h"

using namespace cv;
int main(int agrc, char** argv) {
    Mat src, dst;
    src = imread("L:/6.jpg");
    if (!src.data) {
        printf("could not load image...");
        return -1;
    }

    char INPUT_WIN[] = "input image";
    char OUTPUT_WIN[] = "sample up";
    namedWindow(INPUT_WIN, CV_WINDOW_AUTOSIZE);
    namedWindow(OUTPUT_WIN, CV_WINDOW_AUTOSIZE);
    imshow(INPUT_WIN, src);

    // 上采样
    pyrUp(src, dst, Size(src.cols * 2, src.rows * 2));
    imshow(OUTPUT_WIN, dst);

    // 降采样
    Mat s_down;
    pyrDown(src, s_down, Size(src.cols / 2, src.rows / 2));
    imshow("sample down", s_down);

    // DOG
    Mat gray_src, g1, g2, dogImg;
    cvtColor(src, gray_src, CV_BGR2GRAY);
    GaussianBlur(gray_src, g1, Size(5, 5), 0, 0);
    GaussianBlur(g1, g2, Size(5, 5), 0, 0);
    subtract(g1, g2, dogImg, Mat());  // dogImg =g1 - g2

    // 归一化显示
    normalize(dogImg, dogImg, 255, 0, NORM_MINMAX);
    imshow("DOG Image", dogImg);

    waitKey(0);
    return 0;
}