adaptiveThreshold(~gray_src, binImg, , ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, , -);

#include <opencv2/opencv.hpp>

#include <iostream>

using namespace cv;

int main(int argc, char** argv) {

    Mat src, dst;

    src = imread("E:/opencv3.2/TestOpenCVInstall/Debug/chars.png");

    if (!src.data) {

        printf("could not load image...\n");

        return -;

    }

    char INPUT_WIN[] = "input image";

    char OUTPUT_WIN[] = "result image";

    namedWindow(INPUT_WIN, CV_WINDOW_AUTOSIZE);

    imshow(INPUT_WIN, src);

    Mat gray_src;

    cvtColor(src, gray_src, CV_BGR2GRAY);

    imshow("gray image", gray_src);

    Mat binImg;

    adaptiveThreshold(~gray_src, binImg, , ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, , -);

    imshow("binary image", binImg);

    // 水平结构元素

    Mat hline = getStructuringElement(MORPH_RECT, Size(src.cols / , ), Point(-, -));

    // 垂直结构元素

    Mat vline = getStructuringElement(MORPH_RECT, Size(, src.rows / ), Point(-, -));

    // 矩形结构

    Mat kernel = getStructuringElement(MORPH_RECT, Size(, ), Point(-, -));

    Mat temp;

    erode(binImg, temp, kernel);

    dilate(temp, dst, kernel);

    // morphologyEx(binImg, dst, CV_MOP_OPEN, vline);

    bitwise_not(dst, dst);

    //blur(dst, dst, Size(3, 3), Point(-1, -1));

    imshow("Final Result", dst);

    waitKey();

    return ;

}