Question

初学者。我正试图检测一个圆圈和一只手，并围绕圆圈绘制一个圆圈和一个围绕手的矩形，并在同一图像中显示。当我运行程序时出现内存错误，有人可以帮忙吗？

以下是我的代码：

#include "opencv/cv.h"
#include "opencv2\highgui\highgui.hpp"
#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <conio.h>

using namespace std;

//declarations
IplImage* img = 0;

CvHaarClassifierCascade *cascade;
CvMemStorage *cstorage;
CvMemStorage *hstorage;

void detectObjects( IplImage *img );
int key;

int main( int argc, char** argv )
{
CvCapture *capture;
IplImage *frame;

// loads classifier for hand haar cascade
char *filename = "haarcascade_hand.xml";
cascade = ( CvHaarClassifierCascade* )cvLoad( "haarcascade_hand.xml", 0, 0, 0 );

// setup memory buffer
hstorage = cvCreateMemStorage( 0 );
cstorage = cvCreateMemStorage( 0 );

// initialize camera
capture = cvCaptureFromCAM( 0 );

// always check
//assert( cascade && storage && capture );

// create a window
cvNamedWindow( "Camera", 1 );

while(key!='q') {
    // captures frame and check every frame
    frame = cvQueryFrame( capture );
    if( !frame ) break;

    // detect objects and display video
    detectObjects (frame );

    // quit if user press 'q'
    key = cvWaitKey( 10 );
}

// free memory
cvReleaseCapture( &capture );
cvDestroyAllWindows();
cvReleaseHaarClassifierCascade( &cascade );
cvReleaseMemStorage( &cstorage );
cvReleaseMemStorage( &hstorage );

return 0;
}

void detectObjects( IplImage *img )
{
int px;
int py;
int edge_thresh = 1;
IplImage *gray = cvCreateImage( cvSize(640,480), 8, 1 );
IplImage *edge = cvCreateImage( cvSize(640,480), 8, 1 );

// convert video image color
cvCvtColor(img,gray,CV_BGR2GRAY);                       

// set the converted image's origin
gray->origin=1;                         

// color threshold
cvThreshold(gray,gray,100,255,CV_THRESH_BINARY);    

// smooths out image
cvSmooth(gray, gray, CV_GAUSSIAN, 11, 11);

// get edges
cvCanny(gray, edge, (float)edge_thresh, (float)edge_thresh*3, 5); 

// detects circle
CvSeq* circle =  cvHoughCircles(gray, cstorage, CV_HOUGH_GRADIENT, 1, gray->height/50, 5, 35);

// draws circle and its centerpoint
float* p = (float*)cvGetSeqElem( circle, 0 );
cvCircle( img, cvPoint(cvRound(p[0]),cvRound(p[1])), 3, CV_RGB(255,0,0), -1, 8, 0 );
cvCircle( img, cvPoint(cvRound(p[0]),cvRound(p[1])), cvRound(p[2]), CV_RGB(200,0,0), 1, 8, 0 );
px=cvRound(p[0]); 
py=cvRound(p[1]);

// displays coordinates of circle's center
cout <<"(x,y) -> ("<<px<<","<<py<<")"<<endl;

// detects hand
CvSeq *hand = cvHaarDetectObjects(img, cascade, hstorage, 1.2, 2, CV_HAAR_DO_CANNY_PRUNING, cvSize(100, 100));

// draws red box around hand when detected
CvRect *r = ( CvRect* )cvGetSeqElem( hand, 0 );
cvRectangle( img,
    cvPoint( r->x, r->y ),
    cvPoint( r->x + r->width, r->y + r->height ),
    CV_RGB( 255, 0, 0 ), 1, 8, 0 );

cvShowImage("Camera",img);
}

Answer 1

问题是所创建的灰度图像的大小应与从相机获得的图像的大小相同。

而不是：

IplImage *gray = cvCreateImage( cvSize(640,480), 8, 1 );

将其写为：

IplImage *gray = cvCreateImage( cvSize(img->width,img->height), 8, 1);

Answer 2

从错误消息中，您似乎正在阅读不存在的p[]元素。

您应该检查cvGetSeqElem()是否实际返回了您期望的元素数量 - 可能是Hough例程找不到任何元素。

Answer 3

我有同样的错误！您必须在代码中添加一个if语句，因为当摄像头启动时无法“看到”任何一只手，因此cvGetSeqElem没有得到任何值。试试这个：

if (hand->total >0) {
    CvRect *r = ( CvRect* )cvGetSeqElem( hand, 0 );
    cvRectangle( 
        img,
        cvPoint( r->x, r->y ),
        cvPoint( r->x + r->width, r->y + r->height ),
        CV_RGB( 255, 0, 0 ), 1, 8, 0 
    );
 }

OpenCV中的圆形和手部检测

3 个答案: