Plot a filled black circle on a certain background

I have a 344*344 grey level image with noise only. Now I want to plot a filled black circle in the middle of that gray image as background.

How can I achieve that? And I hope I can also adjust the size (scale) of the filled black circle in the middle of the image.

Thanks so much!!

Answer 1

[Image Analyst]

See the FAQ: https://matlab.fandom.com/wiki/FAQ#How_do_I_create_a_circle.3F