OpenCV + CPP 系列（十七）图像金字塔（上采样 | 降采样）与 高斯差分

文章目录

一、函数介绍

算法详情见：图像金字塔 官方给出了好的示例。

这两个函数参数类似，输入矩阵，输出矩阵，采样后图像大小，边界处理

void pyrDown(
InputArray src, 
OutputArray dst, 
const Size& dstsize = Size(), 
int borderType = BORDER_DEFAULT );
void pyrUp(
InputArray src, 
OutputArray dst, 
const Size& dstsize = Size(), 
int borderType = BORDER_DEFAULT );

二、演示

头文件 quick_opencv.h：声明类与公共函数

#pragma once
#include <opencv2\opencv.hpp>
using namespace cv;

class QuickDemo {
public:
  ...
  void DoG_Demo(Mat& image);
};

主函数调用该类的公共成员函数

#include <opencv2\opencv.hpp>
#include <quick_opencv.h>
#include <iostream>
using namespace cv;


int main(int argc, char** argv) {
  Mat src = imread("D:\\Desktop\\pandas_small22.png");
  if (src.empty()) {
    printf("Could not load images...\n");
    return -1;
  }
  namedWindow("input", WINDOW_NORMAL);
  imshow("input", src);

  QuickDemo qk;
  qk.DoG_Demo(src);
  waitKey(0);
  destroyAllWindows();
  return 0;
}

源文件 quick_demo.cpp：实现类与公共函数

void QuickDemo::DoG_Demo(Mat& image) {
  int height = image.rows;
  int width = image.cols;
  Mat down_dst, up_dst;

  pyrDown(image, down_dst, Size(width / 2, height / 2));
  pyrUp(image, up_dst, Size(width * 2, height * 2));
  imshow("down_dst", down_dst);
  imshow("up_dst", up_dst);

  Mat gray_img, g1, g2, dog_dst, dog_dst2;
  cvtColor(image, gray_img, COLOR_BGR2GRAY);
  

  GaussianBlur(gray_img, g1, Size(3, 3), 0, 0);
  GaussianBlur(g1, g2, Size(3, 3), 0, 0);
  subtract(g1, g2, dog_dst);
  normalize(dog_dst, dog_dst, 255, 0, NORM_MINMAX);

  imshow("gray_img", gray_img);
  imshow("g1", g1);
  imshow("g2", g2);
  imshow("dog_dst", dog_dst);

  applyColorMap(dog_dst, dog_dst2, 2);
  imshow("dog_dst2", dog_dst2);
}

演示效果：