#include "stdafx.h"
#include<iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <string.h>
using namespace cv;
using namespace std;
const string IMAGEPATH = "D:/Program Files/projects/TriggerCount_MutiThread/相机00312779/20171225163059.jpg";//图像路径
Mat preprocess(Mat gray)
{
//1.Sobel算子，x方向求梯度
// Mat sobel;
// Sobel(gray, sobel, CV_8U, 1, 0, 3);
//2.二值化
// Mat binary;
// threshold(sobel, binary, 0, 255, THRESH_OTSU + THRESH_BINARY);
Mat middle;
Mat erzhi(gray.size(), CV_8U, Scalar(0)); //0是黑，255是白
blur(gray, middle, Size(5, 5)); //降噪处理
threshold(middle, erzhi, 60, 255, THRESH_BINARY_INV); //二值化取反
//3.膨胀和腐蚀操作核设定
Mat element1 = getStructuringElement(MORPH_RECT, Size(20, 30));
//控制高度设置可以控制上下行的膨胀程度，例如3比4的区分能力更强,但也会造成漏检
Mat element2 = getStructuringElement(MORPH_RECT, Size(40, 40));
//4.膨胀一次，让轮廓突出
Mat dilate1;
dilate(erzhi, dilate1, element2);
//5.腐蚀一次，去掉细节，表格线等。这里去掉的是竖直的线
Mat erode1;
erode(dilate1, erode1, element1);
//6.再次膨胀，让轮廓明显一些
Mat dilate2;
dilate(erode1, dilate2, element2);
//7.存储中间图片
return dilate2;
}
vector<RotatedRect> findTextRegion(Mat img)
{
vector<RotatedRect> rects;
//1.查找轮廓
vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
findContours(img, contours, hierarchy, RETR_CCOMP, CHAIN_APPROX_SIMPLE, Point(0, 0));
//2.筛选那些面积小的
for (int i = 0; i < contours.size(); i++)
{
//计算当前轮廓的面积
double area = contourArea(contours[i]);
//面积小于1000的全部筛选掉
if (area < 30000)
continue;
//轮廓近似，作用较小，approxPolyDP函数有待研究
double epsilon = 0.001*arcLength(contours[i], true);
Mat approx;
approxPolyDP(contours[i], approx, epsilon, true);
//找到最小矩形，该矩形可能有方向
RotatedRect rect = minAreaRect(contours[i]);
//计算高和宽
int m_width = rect.boundingRect().width;
int m_height = rect.boundingRect().height;
//筛选那些太细的矩形，留下扁的
if (m_height > m_width * 1.2)
continue;
//符合条件的rect添加到rects集合中
rects.push_back(rect);
}
return rects;
}
void detect(Mat img)
{
//1.转化成灰度图
Mat gray;
cvtColor(img, gray, CV_BGR2GRAY);
imshow("gray", gray);
//2.形态学变换的预处理，得到可以查找矩形的轮廓
Mat dilation = preprocess(gray);
//3.查找和筛选文字区域
vector<RotatedRect> rects = findTextRegion(dilation);
//4.用绿线画出这些找到的轮廓
for each (RotatedRect rect in rects)
{
Point2f P[4];
rect.points(P);
for (int j = 0; j <= 3; j++)
{
// line(gray, P[j], P[(j + 1) % 4], Scalar(0, 255, 0), 2);
}
Mat mask = Mat::zeros(img.size(), CV_8UC1);
Rect rect;
rect.x = P[2].x;
rect.y = P[2].y;
rect.width = P[3].x-P[2].x;
rect.height = P[1].y - P[2].y;
//设置矩形掩模
mask(rect).setTo(255);
Mat img2=img(rect);
// img.copyTo(img2, mask);
imshow("img2", img2);
imwrite("数字区域.jpg", img2);
}
//5.显示带轮廓的图像
// imshow("img", img);
waitKey(0);
}
int main()
{
Mat textImageSrc = imread(IMAGEPATH);
detect(textImageSrc);
return 0;
}
