如何计算手指的数量？ （openCV+轮廓检测）

Question

我开始使用 findContour 查找手部轮廓，但是当我想使用 convHull2 和 convextyDefect 计算手指时，我不知道该怎么做。

请你帮助我好吗？这是我的代码：

if( cascade1 )
{
static CvMemStorage* storage4 = 0;
static CvMemStorage* storage5 = 0;
static CvMemStorage* storage6 = 0;
static CvMemStorage* storage7 = 0;


CvSeq* contours;
CvSeq* hand_contour = NULL;

// There can be more than one hand in an image. So create a growable sequence of hands.
// Detect the objects and store them in the sequence
CvSeq* handsO = cvHaarDetectObjects( img, cascade1, storage1,1.1, 2, CV_HAAR_DO_CANNY_PRUNING,cvSize(40, 40) );

storage4 = cvCreateMemStorage(0);
storage5 = cvCreateMemStorage(0);
storage6 = cvCreateMemStorage(0);
storage7 = cvCreateMemStorage(0);

cvClearMemStorage( storage4 );
cvClearMemStorage( storage5 );
cvClearMemStorage( storage6 );
cvClearMemStorage( storage7 );


// Loop the number of hands found.
for( i = 0; i < (handsO ? handsO->total : 0); i++ )
{
    // Create a new rectangle for drawing the hand
    CvRect* r = (CvRect*)cvGetSeqElem( handsO, i );

    // Find the dimensions of the hand,and scale it if necessary
    pt1.x = r->x*scale;
    pt2.x = (r->x+r->width)*scale;
    pt1.y = r->y*scale;
    pt2.y = (r->y+r->height)*scale;

    /////////////////////  start hand contour detection////////////////////////

    // after finding the hand set it as the area of intrest of the image so all of the functions after that will apply only to that area
    cvSetImageROI(Rhand, cvRect(r->x*scale, r->y*scale, r->width*scale, r->height*scale));
    /*
    / prepare the image to the findContour function
    / 1- convert it to gray
    / 2- threshhold it
    / 3- find the edge
    */
    cvShowImage( "gray hand", Rhand);
    cvThreshold( Rhand, Rhand, 1, 255, CV_THRESH_BINARY );
    cvShowImage( "Threshold hand", Rhand);
    cvCanny(Rhand, Rhand, 1, 3, 5);
    cvShowImage( "Edge hand", Rhand);

    /*
    // cloasing after threshold to test if it will be a beter result 
    IplConvKernel* kernel = 0;
    kernel = cvCreateStructuringElementEx(5,5,0,0, CV_SHAPE_RECT);
    cvDilate(Rhand,Rhand,kernel,1);
    cvErode(Rhand,Rhand,kernel,1);
    */


    // find all contour  in the image
    cvFindContours(Rhand,storage4,&contours,sizeof(CvContour),CV_RETR_LIST,CV_CHAIN_APPROX_SIMPLE,cvPoint(0,0));

//  printf("\ncontour num%d",contours->total);
    // find the beggest contour and make it as the hand by comaring the area of each contour
    double area=0,biggestArea=0;
    while(contours)
    {
        area = fabs( cvContourArea( contours, CV_WHOLE_SEQ ) );
        //printf("\n\\\\\\\\\\\\\\\\\\\\\%f",area);

        if ( area > biggestArea) 
        {
        biggestArea = area; 
        hand_contour = contours;
        //printf("\n\\\\\\\\\\\\\\\\\\\\biggest\\\\\\\\\\\\\\%d",hand_contour->total);
        };

        contours  =  contours->h_next;
    }

    cvWaitKey(0);       

    if(hand_contour)
    {

        hand_contour = cvApproxPoly( hand_contour, sizeof(CvContour), storage7, CV_POLY_APPROX_DP, 3, 1 );
        CvRect rect = cvBoundingRect(hand_contour, 1 );
        CvBox2D box = cvMinAreaRect2( hand_contour, storage6 );
        //draw the rectangle arround the contour
        cvRectangle( img, cvPoint(rect.x, rect.y + rect.height), cvPoint(rect.x + rect.width, rect.y), CV_RGB(255, 255, 0), 1, 8, 0 );

        // preparing to detect the finger and compute/ draw them
        CvSeq* hull = cvConvexHull2( hand_contour, 0, CV_CLOCKWISE, 0 );
        int numOfHull =hull->total;
        CvPoint*  hullPoints;
        hullPoints = ( CvPoint *)malloc((hull->total)*sizeof(CvSeq));
        cvCvtSeqToArray(hull,hullPoints);           

        CvSeq* defect = cvConvexityDefects( hand_contour, hull, storage5 );
        int numOfdefect =defect->total;
        CvConvexityDefect* defectArray;
        defectArray = (CvConvexityDefect*)malloc(sizeof(CvConvexityDefect)*numofdefect);  
        cvCvtSeqToArray(defect,defectArray); 

        /*int h1,h2;
        for(i=0; i<numofHull-1; i++)  
        { 
            h1=hull[i];
            h2=hull[i+1];
            cvLine(img, defectArray[h1],defectArray[h2],CV_RGB(255,255,255),1, CV_AA, 0 );  
        }
        int h3=hull[numofHull-1],h4=hull[0];
        cvLine(img, defectArray[h3],defectArray[h4],CV_RGB(255,255,255),1, CV_AA, 0 );  
       // Free memory.            
       free(defectArray);  
       free(hull);  */

       int m=10;
        //cvPolyLine(img,&hullPoints,&m,CV_RGB( 0, 0, 100),1,8,0);
        //cvPolyLine( img, &hullPoints, &m, 2, 0, CV_RGB(0,0,100),10, CV_AA, 0);

        cvCircle( img, cvPoint(pt1.x, pt1.y), 3, CV_RGB(255, 128, 0), 3, 8, 0 );    
        cvCircle( img, cvPoint(box.center.x, box.center.y), 3, CV_RGB(75, 243, 243), 1, 8, 0 );
        cvEllipse( img, cvPoint(pt1.x, pt1.y), cvSize(box.size.height/2, box.size.width/2), box.angle, 0, 360, CV_RGB(220, 0, 120), 2, 8, 0 );
        cvDrawContours( Rhand, hand_contour,  CV_RGB( 0, 200, 100), CV_RGB( 100, 0, 0), 1, 1, 8, cvPoint(pt1.x,pt1.y));
        cvDrawContours( img, hand_contour,  CV_RGB( 0, 200, 100), CV_RGB( 100, 0, 0), 1, 1, 8, cvPoint(pt1.x,pt1.y));
        cvShowImage( "Rhand after draw contour", Rhand);
        cvShowImage( "img After draw contour", img);

        cvResetImageROI(Rhand);
        ///////////////////// End hand contour detection////////////////////////
}
// Draw the rectangle in the input image
 cvRectangle( img, pt1, pt2, CV_RGB(0,255,0), 3, 8, 0 );
}
cvClearSeq(handsO);
}

Answer 1

我不确定代码，因为我自己刚刚学习这个，但由于 cvConvexityDefect 为您提供了深度，您可以迭代所有缺陷并检查该值是否落在您期望的从指尖到手。您需要检查您的手，并根据您能看到的手指数量计算出有多少缺陷。