how to save ROI's detected in an image

edit

Hi; In my project, i can extract Roi's from labelled image but i didn't know how to save them for a later use .i work with cvBlob to extract blobs . here is the procedure witch extract roi but it shows only the last Roi and not all of them.Can you help me please?

void extraireROI(IplImage* img,CvBlob *blob)
    {
    int heigth =(blob->maxy)- (blob->miny);
    int width=(blob->maxx)- (blob->minx);
    int x=blob->minx;
    int y=blob->miny;
    cvSetImageROI(img,cvRect(x, y, width, heigth));
    IplImage* img2=cvCreateImage(cvGetSize(img),img->depth, 3);
    cvCopy(img, img2, NULL);

    /* always reset the Region of Interest */
    cvResetImageROI(img);
    cvShowImage("ROI extraite ",img2);
    }
void labelImage(IplImage *binaire,IplImage *img )
    {

    // Label image and extract informations 
   IplImage *labelImg=cvCreateImage(cvGetSize(binaire), IPL_DEPTH_LABEL, 1);
    CvBlobs blobs;
     IplImage *roi;
    unsigned int result=cvLabel(binaire, labelImg, blobs);
     FilterArea(blobs, 500, 250000);
    cvRenderBlobs(labelImg, blobs, img, img);
     CvBlobs::iterator it=blobs.begin();
    while(it!=blobs.end())
    {
      CvBlob *blob=(*it).second;
      extraireROI(img,blob);
      cout << "Blob #" << it->second->label << ": Area=" << it->second->area << ", Centroid=(" << it->second->centroid.x << ", " << it->second->centroid.y << ")" << endl;
      it++;  
    }
    cvShowImage("image labellisée ",img);
    }