每天一点matlab——如何将一幅图像（640*360）分成4个局域（160*90）读取

clear all
clc
close all
Img=imread('C:\Documents and Settings\Administrator\桌面\b.jpg');
%图像分成mxn块
m=4;
n=4;
[sample_h sample_w]=size(Img);%读入图像的高和宽 640 360
region_h=floor(sample_h/m);%每个区域的高 160
region_w=floor(sample_w/n);%每个区域的宽 90
plot_num=1;
figure
imshow(Img)
title('原图像')

figure
for i=1:m
    for j=1:n
        temp=Img((i-1)*region_h+1:i*region_h,(j-1)*region_w+1:j*region_w);%每个区域的信息
        subplot(4,4,plot_num);
        imshow(temp)
        plot_num=plot_num+1;
    end
end