How to convert red channel of a rgb image to grayscale image?

I have some rgb images. I want to know is there any way to only convert the red channel of them to grayscale?

Answer 1

[Image Analyst]

Yes. Very easy:

redChannel = rgbImage(:, :, 1); % Extract the red channel only into a gray scale image.

[Ghazal Hnr]

I did that before, but in the article that I working on had been said that:

Is this just mean extracting the red channel?

[Image Analyst]

That is a bad explanation and they should know better. When you extract the red channel, it is already a grayscale image at that point -- there is no need for a second step of converting it to a gray scale image.

[Ghazal Hnr]

Thank you for your response.