基于椭圆模型的肤色检测

算法思想：主要判断YCrCb空间中以（Cr， Cb）为坐标的点是否落在肤色椭圆内，如果在椭圆内，则为肤色点。
注：RGB空间转换为YCrCb空间时要以为坐标（Cb， Cr），BGR空间转换为YCrCb空间时，要以（Cr， Cb）为坐标。

void skin_Ellipse(Mat * src, Mat * mask)
{
    Mat srcImg;
    src->copyTo (srcImg);
    //定义肤色椭圆模型
    Mat skinEllipse = Mat::zeros(Size(256,256), CV_8UC1 );
    ellipse (skinEllipse, Point(113, 155.6), Size(23.4,15.2),43.0, 0.0, 360, Scalar (255,255,255),-1);//画填充的椭圆区
    imshow("skinEllipse", skinEllipse );
    //定义模板mask
    //Mat mask = Mat::zeros(srcImg.size(), CV_8UC1 );
    //将BGR转换为YCrCb空间
    Mat ycrcbImg;
    cvtColor (srcImg, ycrcbImg, CV_BGR2YCrCb );
    imshow("ycrcbImg",ycrcbImg );
    Mat Cr_Img, Cb_Img;
    //肤色检测
    for (int i = 0; i < ycrcbImg.rows; i++)
        for (int j = 0; j < ycrcbImg.cols; j++)
        {
            Vec3b ycrcb = ycrcbImg.at(i,j);
            if (skinEllipse.at<uchar>(ycrcb[1], ycrcb[2]) > 0)
                mask->at<uchar>(i,j) =255;
        }
        imshow("Ellipse_mask",*mask);

}

参考文献
http://www.cnblogs.com/tornadomeet/archive/2012/12/05/2802428.html
https://blog.csdn.net/qq_29540745/article/details/52589008
https://blog.csdn.net/zdx19880830/article/details/45892739
https://blog.csdn.net/wj080211140/article/details/23384927