hough变换 矩形检测

//#include "cv.h"//#include "highgui.h"#include<opencv2/core/core.hpp>#include<opencv2/highgui/highgui.hpp>#include<opencv2/imgproc/imgproc.hpp>#include<opencv2/opencv.hpp>#include <stdio.h>#include <math.h>#include <string.h>#include <iostream>#include <fstream>#include <sstream>#include <io.h>#include <atlbase.h>using namespace std;using namespace cv;int thresh = 50;IplImage* img = NULL;IplImage* img0 = NULL;CvMemStorage* storage = NULL;const char * wndname = "正方形检测 demo";//angle函数用来返回（两个向量之间找到角度的余弦值）double angle(CvPoint* pt1, CvPoint* pt2, CvPoint* pt0){double dx1 = pt1->x - pt0->x;double dy1 = pt1->y - pt0->y;double dx2 = pt2->x - pt0->x;double dy2 = pt2->y - pt0->y;return (dx1*dx2 + dy1*dy2) / sqrt((dx1*dx1 + dy1*dy1)*(dx2*dx2 + dy2*dy2) + 1e-10);}// 返回图像中找到的所有轮廓序列，并且序列存储在内存存储器中CvSeq* findSquares4(IplImage* img, CvMemStorage* storage){CvSeq* contours;int i, c, l, N = 11;CvSize sz = cvSize(img->width & -2, img->height & -2);IplImage* timg = cvCloneImage(img);IplImage* gray = cvCreateImage(sz, 8, 1);IplImage* pyr = cvCreateImage(cvSize(sz.width / 2, sz.height / 2), 8, 3);IplImage* tgray;CvSeq* result;double s, t;// 创建一个空序列用于存储轮廓角点CvSeq* squares = cvCreateSeq(0, sizeof(CvSeq), sizeof(CvPoint), storage);cvSetImageROI(timg, cvRect(0, 0, sz.width, sz.height));// 过滤噪音cvPyrDown(timg, pyr, 7);cvPyrUp(pyr, timg, 7);tgray = cvCreateImage(sz, 8, 1);// 红绿蓝3色分别尝试提取for (c = 0; c < 3; c++){// 提取 the c-th color planecvSetImageCOI(timg, c + 1);cvCopy(timg, tgray, 0);// 尝试各种阈值提取得到的（N=11）for (l = 0; l < N; l++){// apply Canny. Take the upper threshold from slider// Canny helps to catch squares with gradient shading  if (l == 0){cvCanny(tgray, gray, 0, thresh, 5);//使用任意结构元素膨胀图像cvDilate(gray, gray, 0, 1);}else{// apply threshold if l!=0:cvThreshold(tgray, gray, (l + 1) * 255 / N, 255, CV_THRESH_BINARY);}// 找到所有轮廓并且存储在序列中cvFindContours(gray, storage, &contours, sizeof(CvContour),CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0, 0));// 遍历找到的每个轮廓contourswhile (contours){//用指定精度逼近多边形曲线result = cvApproxPoly(contours, sizeof(CvContour), storage,CV_POLY_APPROX_DP, cvContourPerimeter(contours)*0.02, 0);if (result->total == 4 &&fabs(cvContourArea(result, CV_WHOLE_SEQ)) > 500 &&fabs(cvContourArea(result, CV_WHOLE_SEQ)) < 100000 &&cvCheckContourConvexity(result)){s = 0;for (i = 0; i < 5; i++){// find minimum angle between joint edges (maximum of cosine)if (i >= 2){t = fabs(angle((CvPoint*)cvGetSeqElem(result, i),(CvPoint*)cvGetSeqElem(result, i - 2),(CvPoint*)cvGetSeqElem(result, i - 1)));s = s > t ? s : t;}}// if 余弦值 足够小，可以认定角度为90度直角//cos0.1=83度，能较好的趋近直角if (s < 0.1)for (i = 0; i < 4; i++)cvSeqPush(squares,(CvPoint*)cvGetSeqElem(result, i));}// 继续查找下一个轮廓contours = contours->h_next;}}}cvReleaseImage(&gray);cvReleaseImage(&pyr);cvReleaseImage(&tgray);cvReleaseImage(&timg);return squares;}//drawSquares函数用来画出在图像中找到的所有正方形轮廓void drawSquares(IplImage* img, CvSeq* squares){CvSeqReader reader;IplImage* cpy = cvCloneImage(img);int i;cvStartReadSeq(squares, &reader, 0);// read 4 sequence elements at a time (all vertices of a square)for (i = 0; i < squares->total; i += 4){CvPoint pt[4], *rect = pt;int count = 4;// read 4 verticesCV_READ_SEQ_ELEM(pt[0], reader);CV_READ_SEQ_ELEM(pt[1], reader);CV_READ_SEQ_ELEM(pt[2], reader);CV_READ_SEQ_ELEM(pt[3], reader);// draw the square as a closed polylinecvPolyLine(cpy, &rect, &count, 1, 1, CV_RGB(0, 255, 0), 2, CV_AA, 0);}cvShowImage(wndname, cpy);/*const char* filename = "111111111111111111111.jpg";const CvArr* image = cpy;int cvSaveImage("1111111111111111111111.jpg",image);*/char* filename2 = "E:\\大贝壳\\C++\\opencvBlog\\Project1\\Project1\\pic\\Rect_img_233.jpg"; //图像名cvSaveImage(filename2, cpy);//把图像写入文件Mat mtx(cpy);cvReleaseImage(&cpy);}char* names[] = { "img_233.jpg", 0 };int main(int argc, char** argv){int i, c;storage = cvCreateMemStorage(0);for (i = 0; names[i] != 0; i++){img0 = cvLoadImage(names[i], 1);if (!img0){cout << "不能载入" << names[i] << "继续下一张图片" << endl;continue;}img = cvCloneImage(img0);cvNamedWindow(wndname, 1);// find and draw the squaresdrawSquares(img, findSquares4(img, storage));c = cvWaitKey(0);cvReleaseImage(&img);cvReleaseImage(&img0);cvClearMemStorage(storage);if ((char)c == 27)break;}cvDestroyWindow(wndname);return 0;}