【opencv】矩形检测

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#include "cv.h"#include "highgui.h"#include <stdio.h>#include <math.h>#include <string.h>////////////////////////////////////////////////////////////////////函数功能：用向量来做COSα=两向量之积/两向量模的乘积求两条线段夹角//输入：   线段3个点坐标pt1,pt2,pt0,最后一个参数为公共点//输出：   线段夹角，单位为角度//////////////////////////////////////////////////////////////////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;        double angle_line = (dx1*dx2 + dy1*dy2)/sqrt((dx1*dx1 + dy1*dy1)*(dx2*dx2 + dy2*dy2) + 1e-10);//余弦值    return acos(angle_line)*180/3.141592653; }////////////////////////////////////////////////////////////////////函数功能：采用多边形检测，通过约束条件寻找矩形//输入：   img 原图像//          storage 存储//          minarea，maxarea 检测矩形的最小/最大面积//          minangle,maxangle 检测矩形边夹角范围，单位为角度//输出：   矩形序列//////////////////////////////////////////////////////////////////CvSeq* findSquares4( IplImage* img, CvMemStorage* storage ,int minarea, int maxarea, int minangle, int maxangle){      CvSeq* contours;//边缘    int N = 6;  //阈值分级    CvSize sz = cvSize( img->width & -2, img->height & -2 );    IplImage* timg = cvCloneImage( img );//拷贝一次img    IplImage* gray = cvCreateImage( sz, 8, 1 ); //img灰度图    IplImage* pyr = cvCreateImage( cvSize(sz.width/2, sz.height/2), 8, 3 );  //金字塔滤波3通道图像中间变量    IplImage* tgray = cvCreateImage( sz, 8, 1 ); ;       CvSeq* result;      double s, t;      CvSeq* squares = cvCreateSeq( 0, sizeof(CvSeq), sizeof(CvPoint), storage );       cvSetImageROI( timg, cvRect( 0, 0, sz.width, sz.height ));       //金字塔滤波     cvPyrDown( timg, pyr, 7 );      cvPyrUp( pyr, timg, 7 );       //在3个通道中寻找矩形     for( int c = 0; c < 3; c++ ) //对3个通道分别进行处理     {               cvSetImageCOI( timg, c+1 );             cvCopy( timg, tgray, 0 );  //依次将BGR通道送入tgray                 for( int l = 0; l < N; l++ )             {                     //不同阈值下二值化            cvThreshold( tgray, gray, (l+1)*255/N, 255, CV_THRESH_BINARY );            cvFindContours( gray, storage, &contours, sizeof(CvContour),CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0) );                      while( contours )                { //多边形逼近                           result = cvApproxPoly( contours, sizeof(CvContour), storage,CV_POLY_APPROX_DP, cvContourPerimeter(contours)*0.02, 0 );                 //如果是凸四边形并且面积在范围内              if( result->total == 4 && fabs(cvContourArea(result,CV_WHOLE_SEQ)) > minarea  && fabs(cvContourArea(result,CV_WHOLE_SEQ)) < maxarea &&  cvCheckContourConvexity(result) )                  {                                   s = 0;                          //判断每一条边                    for( int i = 0; i < 5; i++ )                      {                                           if( i >= 2 )                                   {   //角度                                        t = fabs(angle( (CvPoint*)cvGetSeqElem( result, i ),(CvPoint*)cvGetSeqElem( result, i-2 ),(CvPoint*)cvGetSeqElem( result, i-1 )));                               s = s > t ? s : t;                             }                             }                       //这里的S为直角判定条件 单位为角度                    if( s > minangle && s < maxangle )                                              for( int i = 0; i < 4; i++ )                                          cvSeqPush( squares,(CvPoint*)cvGetSeqElem( result, i ));                     }                                                      contours = contours->h_next;                  }           }     }    cvReleaseImage( &gray );       cvReleaseImage( &pyr );      cvReleaseImage( &tgray );      cvReleaseImage( &timg );       return squares;}  ////////////////////////////////////////////////////////////////////函数功能：画出所有矩形//输入：   img 原图像//          squares 矩形序列//          wndname 窗口名称//输出：   图像中标记矩形//////////////////////////////////////////////////////////////////void drawSquares( IplImage* img, CvSeq* squares ,const char* wndname){       CvSeqReader reader;       IplImage* cpy = cvCloneImage( img );       CvPoint pt[4];    int i;           cvStartReadSeq( squares, &reader, 0 );         for( i = 0; i < squares->total; i += 4 )      {               CvPoint* rect = pt;            int count = 4;              memcpy( pt, reader.ptr, squares->elem_size );         CV_NEXT_SEQ_ELEM( squares->elem_size, reader );         memcpy( pt + 1, reader.ptr, squares->elem_size );             CV_NEXT_SEQ_ELEM( squares->elem_size, reader );           memcpy( pt + 2, reader.ptr, squares->elem_size );           CV_NEXT_SEQ_ELEM( squares->elem_size, reader );             memcpy( pt + 3, reader.ptr, squares->elem_size );          CV_NEXT_SEQ_ELEM( squares->elem_size, reader );                 //cvPolyLine( cpy, &rect, &count, 1, 1, CV_RGB(0,255,0), 3, CV_AA, 0 );        cvPolyLine( cpy, &rect, &count, 1, 1, CV_RGB(rand()&255,rand()&255,rand()&255), 1, CV_AA, 0 );//彩色绘制    }            cvShowImage( wndname, cpy );      cvReleaseImage( &cpy );}int main(){        CvCapture* capture = cvCreateCameraCapture(0);    IplImage* img0 = 0;    CvMemStorage* storage = 0;    int c;     const char* wndname = "Square Detection Demo"; //窗口名称    storage = cvCreateMemStorage(0);        cvNamedWindow( wndname, 1 );        while (true)    {        img0 = cvQueryFrame(capture);              drawSquares( img0, findSquares4( img0, storage, 100, 2000, 80, 100), wndname );        cvClearMemStorage( storage );  //清空存储        c = cvWaitKey(10);         if( c == 27 )               break;      }    cvReleaseImage( &img0 );           cvClearMemStorage( storage );      cvDestroyWindow( wndname );       return 0;}
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