'Return an image that contains just pixels defined by the blob sequence.'

def _getBlobAsImage(self, seq, bb, colorbitmap, mask):

    cv.SetImageROI(colorbitmap, bb)
    outputImg = cv.CreateImage((bb[2], bb[3]), cv.IPL_DEPTH_8U, 3)
    cv.Zero(outputImg)
    cv.Copy(colorbitmap, outputImg, mask)
    cv.ResetImageROI(colorbitmap)
    return Image(outputImg)
