MATLAB划分一个形状为圆的区域

下文中的代码用于提取图像的中心圆域，原理很简单，就是圆的计算公式。

%% ----------------------------------%%  DOCUMENT TITLE: draw a circle%%  AUTHOR: [e-mail]%% ----------------------------------clear all;clc;%parametersdimention = 1000;radius = 500;xx = zeros(dimention, dimention);center_x = round(size(xx,1)/2);center_y = round(size(xx,2)/2);% start to draw circlefor i = 1: size(xx, 1)    for j = 1: size(xx,2)        temp = sqrt((i-center_x)^2+(j-center_y)^2);        if(temp <= radius)            xx(i, j) = 1;        end    endend% show the figurefigure;imshow(xx);title('this is a circle');