opencv4 学习 11 padding 操作

1. opencv内置函数的使用：
copyMakeBorder(InputArray src, OutputArray dst, int top, int bottom, int left, int right, int borderType, const Scalar &value)
其中 borderType 参数支持两种模式：

• BORDER_CONSTANT: Pad the image with a constant value 
• BORDER_REPLICATE: The row or column at the very edge of the original is replicated to the extra border。

int top, int bottom, int left, int right：分别表示各个方向的填充尺寸。

#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <iostream>

using namespace cv;

Mat src, dst;
int top, bottom, left=0, right=0; // border size
int borderType = BORDER_CONSTANT;
const char* window_name = "copyMakeBorder Demo";
RNG rng(12345);

int main(int arc, char* argv){
    const char* imageName = "lena.jpg";
    src = imread(imageName, IMREAD_COLOR);

    top = (int)(0.05*src.rows); bottom = top;
    left = (int)(0.05*src.cols); right = left;

    for(;;){
        Scalar value(rng.uniform(0,255), rng.uniform(0, 255), rng.uniform(0, 255));
        copyMakeBorder(src, dst, top, bottom, left, right, borderType, value);
        imshow(window_name, dst);

        char c = (char)waitKey(500);
        if(c == 27) break;
        if(c == 'c') borderType = BORDER_CONSTANT;
        if(c == 'r') borderType = BORDER_REPLICATE;
    }
    std::cout << src.rows  << dst.rows  << left << std::endl;
    return 0;
}

 

参考：

https://docs.opencv.org/3.4/dc/da3/tutorial_copyMakeBorder.html