insert circle values in 512x512 matrix

I need create a 512x512 matrix, with the border parts geting the 0 value and the central part of matrix geting 1 value. The goal is create a mask of an image. How I solve this problem?

Answer 1

[Walter Roberson]

M = ones(512,512);
M([1 end], :) = 0;
M(:, [1 end]) = 0;

Or perhaps you are looking for https://matlab.fandom.com/wiki/FAQ#How_do_I_create_a_circle.3F