[MATLAB图像处理] 图像序列中维数不匹配的问题

[imu0471]

Matlab程序出错??? Subscripted assignment dimension mismatch.
I=ones(8,5);
q=reshape(49:56,8,1);
I(:,1)=q;
I(:,2)='.';
I(:,3)='b';
I(:,4)='m';
I(:,5)='p';
L=setstr(I); %将ASCII码转为字符串；

c=imread(L(1,);
[m n]=size(c);
I0=uint8(ones(m,n,8));
for k=1:8
j=imread(L(k,);
I0(:,:,k)=j;
end
[m n o]=size(I0);
Q=uint8(ones(m,n));
程序运行到 I0(:,:,k)=j;
就会出现错误，错误信息提示：
??? Subscripted assignment dimension mismatch.
Error in ==> backgroundtest3 at 18
I0(:,:,k)=j;