更改通过cvGrabCut（）C＃获得的前景图像的背景色

Question

I have used cvGrabCut() method from emgu cv in c# to extract foreground image. The result is satisfactory and I can extract foreground image with black background. But now I have to change the obtained black color background image to some different color. How can I do that? I have used the following code for foreground extraction:

mask1.Draw(rect, new Gray(3), 0);
//the models (internally used)
Matrix<double> bgModel = new Matrix<double>(1, 13 * 5);
Matrix<double> fgModel = new Matrix<double>(1, 13 * 5);
//initialization with mask
CvInvoke.CvGrabCut(image.Ptr, mask1.Ptr, ref rect, bgModel.Ptr, fgModel.Ptr, 10, Emgu.CV.CvEnum.GRABCUT_INIT_TYPE.INIT_WITH_MASK);
//GrabCut segmentation
CvInvoke.CvGrabCut(image.Ptr, mask1.Ptr, ref rect, bgModel.Ptr, fgModel.Ptr, 15, Emgu.CV.CvEnum.GRABCUT_INIT_TYPE.EVAL);
//Get the pixels marked as likely foreground
mask1 = mask1.And(new Gray(1));
Image<Bgr, Byte> result = image.Copy(mask1);
result.Save("foreground.jpg");

Answer 1

From the documentation it looks like you should change one or both of the 'new Gray(n)' with a 'new Bgr(b,g,r)' where the characters are respectively blue, green, and red (as in reverse RGB).

Look here Documentation

Answer 2

After getting the result from grabcut, you can iterate through the image and check for black pixels in 3-channels(RGB). Just replace the corresponding color values for those detected black pixels. Sample:

rows,cols = output.shape[:2]

b,g,r = cv2.split(output)
    for i in range(rows):
        for j in range(cols):
            if(r[i, j] == 0 and g[i, j] == 0 and b[i, j] == 0):
                r[i, j] = 255
                g[i, j] = 255
                b[i, j] = 255

Here i am changing from black to white. But this code is in python. You can do similar in c#.