如何从图像提取面部？

问题描述

我已使用 OpenCv 成功侦测到背景中有其他东西的图​​片。
现在我需要只提取被检测的部分（ie face），并将其转换成一些图像格式，如 jpeg 或 gif

I have successfully detected a face out of an image having other things in background using OpenCv.Now I need to extract just the detected part (i.e. face) and convert it into some image format like jpeg or gif to make a face database to use for my neural net training.

我如何做到这一点？

推荐答案

一旦你检测到面部，你会得到一个矩形的对角，用于在面部绘制矩形。

Once you detect the faces, you get opposite corners of a rectangle, which is used to draw rectangles around the face.

现在您可以设置图像ROI（感兴趣区域），裁剪ROI并将其另存为另一个图像。

Now you can set image ROI ( Region of Interest) , crop the ROI and save it as another image.

/* After detecting the rectangle points, Do as follows */
/* sets the Region of Interest
   Note that the rectangle area has to be __INSIDE__ the image */
cvSetImageROI(img1, cvRect(10, 15, 150, 250));

/* create destination image
   Note that cvGetSize will return the width and the height of ROI */
IplImage *img2 = cvCreateImage(cvGetSize(img1),
                               img1->depth,
                               img1->nChannels);

/* copy subimage */
cvCopy(img1, img2, NULL);

/* always reset the Region of Interest */
cvResetImageROI(img1);

上述代码取自）

进一步 cvSaveImage 函数可用于将图像保存到文件。

Further cvSaveImage function can be used to save image to a file.

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