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我用程序检测图像中的正方形。这与我从互联网下载的图像效果很好。但我应该做的是检测从相机拍摄的图像的正方形。首先我从视频中提取图像,然后尝试从这些图像集合中检测出正方形,但代码不适用于那些提取的图像(但与其他图像协同工作)。我该怎么做才能完成这项任务?使用opencv2.4检测正方形
#ifdef _CH_
#pragma package <opencv>
#endif
#define CV_NO_BACKWARD_COMPATIBILITY
#include <opencv2/opencv.hpp>
#include "stdafx.h"
#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <math.h>
#include <string.h>
int thresh = 50;
IplImage* img = 0;
IplImage* img0 = 0;
CvMemStorage* storage = 0;
//const char* wndname = "Square Detection Demo";
// helper function:
// finds a cosine of angle between vectors
// from pt0->pt1 and from pt0->pt2
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);
}
// returns sequence of squares detected on the image.
// the sequence is stored in the specified memory storage
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); // make a copy of input image
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;
// create empty sequence that will contain points -
// 4 points per square (the square's vertices)
CvSeq* squares = cvCreateSeq(0, sizeof(CvSeq), sizeof(CvPoint), storage);
// select the maximum ROI in the image
// with the width and height divisible by 2
cvSetImageROI(timg, cvRect(0, 0, sz.width, sz.height));
// down-scale and upscale the image to filter out the noise
cvPyrDown(timg, pyr, 7);
cvPyrUp(pyr, timg, 7);
tgray = cvCreateImage(sz, 8, 1);
// find squares in every color plane of the image
for(c = 0; c < 3; c++)
{
// extract the c-th color plane
cvSetImageCOI(timg, c+1);
cvCopy(timg, tgray, 0);
// try several threshold levels
for(l = 0; l < N; l++)
{
// hack: use Canny instead of zero threshold level.
// Canny helps to catch squares with gradient shading
if(l == 0)
{
// apply Canny. Take the upper threshold from slider
// and set the lower to 0 (which forces edges merging)
cvCanny(tgray, gray, 0, thresh, 5);
// dilate canny output to remove potential
// holes between edge segments
cvDilate(gray, gray, 0, 1);
}
else
{
// apply threshold if l!=0:
// tgray(x,y) = gray(x,y) < (l+1)*255/N ? 255 : 0
cvThreshold(tgray, gray, (l+1)*255/N, 255, CV_THRESH_BINARY);
}
// find contours and store them all as a list
cvFindContours(gray, storage, &contours, sizeof(CvContour),
CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0));
// test each contour
while(contours)
{
// approximate contour with accuracy proportional
// to the contour perimeter
result = cvApproxPoly(contours, sizeof(CvContour), storage,
CV_POLY_APPROX_DP, cvContourPerimeter(contours)*0.02, 0);
// square contours should have 4 vertices after approximation
// relatively large area (to filter out noisy contours)
// and be convex.
// Note: absolute value of an area is used because
// area may be positive or negative - in accordance with the
// contour orientation
if(result->total == 4 &&
cvContourArea(result,CV_WHOLE_SEQ,0) > 1000 &&
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 cosines of all angles are small
// (all angles are ~90 degree) then write quandrange
// vertices to resultant sequence
if(s < 0.3)
for(i = 0; i < 4; i++)
cvSeqPush(squares,
(CvPoint*)cvGetSeqElem(result, i));
}
// take the next contour
contours = contours->h_next;
}
}
}
// release all the temporary images
cvReleaseImage(&gray);
cvReleaseImage(&pyr);
cvReleaseImage(&tgray);
cvReleaseImage(&timg);
return squares;
}
// the function draws all the squares in the image
void drawSquares(IplImage* img, CvSeq* squares)
{
CvSeqReader reader;
IplImage* cpy = cvCloneImage(img);
int i;
// initialize reader of the sequence
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 vertices
CV_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 polyline
cvPolyLine(cpy, &rect, &count, 1, 1, CV_RGB(0,255,0), 3, CV_AA, 0);
}
// show the resultant image
cvShowImage("Square Detection Demo", cpy);
cvReleaseImage(&cpy);
}
//char* names[] = { "pic1.png", "pic2.png", "pic3.png",
// "pic4.png", "pic5.png", "pic6.png", 0 };
int main(int argc, char** argv)
{
int i, c;
// create memory storage that will contain all the dynamic data
storage = cvCreateMemStorage(0);
//for(i = 0; names[i] != 0; i++)
//{
// // load i-th image
// img0 = cvLoadImage(names[i], 1);
// if(!img0)
// {
// printf("Couldn't load %s\n", names[i]);
// continue;
// }
img0 = cvLoadImage("frame_21.jpg");
img = cvCloneImage(img0);
// create window and a trackbar (slider) with parent "image" and set callback
// (the slider regulates upper threshold, passed to Canny edge detector)
// cvNamedWindow("qq");
// find and draw the squares
drawSquares(img, findSquares4(img, storage));
// wait for key.
// Also the function cvWaitKey takes care of event processing
c = cvWaitKey(0);
// release both images
cvReleaseImage(&img);
cvReleaseImage(&img0);
// clear memory storage - reset free space position
cvClearMemStorage(storage);
/*if((char)c == 27)
break;*/
/* }*/
// cvDestroyWindow("qq");
return 0;
}
这是从视频----->萃取
感谢您replying.yes我也有,我从互联网上下载和代码给正确的输出多个图像检查代码。但事情是我应该开发一个检测道路标志的系统。系统从摄像头捕捉视频,然后从视频中提取帧。我将从这些提取的图像中检测具有方形板(可能是道路标志或广告板)的帧,并将这些帧(其具有正方形)发送到其他功能以用于更多作品。附加提取的图像之一这个问题。有没有解决这个问题的方法。 – Thar1988 2012-08-11 12:23:54