OpenCV 提取水平或垂直线，过滤细 小杂质

灰度化 -> 二值化 -> 建立满足不同需求的结构元素 -> 开运算

若要去除垂直线，则建立水平长条状矩形结构元素

若要去除水平线，则建立垂直长条状矩形结构元素

#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;



int main() {
    Mat src1, src2, gray_src, dst;
    src1 = imread("/Users/apple/Desktop/chars.png", IMREAD_COLOR);
    //src2 = imread("/Users/apple/Desktop/test2.jpg", IMREAD_COLOR);
    if (src1.empty()) { // if (!src.data())
        cout << "could not load image..." << endl;
        return -1;
    }
    imshow("input", src1);
    
    cvtColor(src1, gray_src, CV_BGR2GRAY);
    imshow("output_gray", gray_src);
    
    Mat binImg;
    adaptiveThreshold(~gray_src, binImg, 255, ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, 25, -2);
    Mat kernel = getStructuringElement(MORPH_RECT, Size(4, 4), Point(-1, -1));
    //morphologyEx(binImg, binImg, MORPH_OPEN, kernel);
    imshow("output binary image", binImg);
    
    // 水平结构元素
    Mat hline = getStructuringElement(MORPH_RECT, Size(src1.cols / 16, 1), Point(-1, -1));
    
    // 垂直结构元素
    Mat vline = getStructuringElement(MORPH_RECT, Size(1, src1.rows / 16), Point(-1, -1));
    
    
    
    Mat temp;
    erode(binImg, temp, kernel);
    dilate(temp, dst, kernel);
    
    imshow("temp", temp);
    imshow("output", ~dst);
    waitKey(0);
    
    return 0;
}