matlab - 展开和裁剪矩阵

Question

如何扩展边缘周围为零的矩阵，然后在进行一些操作后将其裁剪回相同的大小？

Answer 1

你可以这样做:

octave:1> x = ones(3, 4)
x =

   1   1   1   1
   1   1   1   1
   1   1   1   1

octave:2> y = zeros(rows(x)+2, columns(x)+2);
octave:3> y(2:rows(x)+1, 2:columns(x)+1) = x
y =

   0   0   0   0   0   0
   0   1   1   1   1   0
   0   1   1   1   1   0
   0   1   1   1   1   0
   0   0   0   0   0   0

octave:4> y = y.*2  (manipulation)
y =

   0   0   0   0   0   0
   0   2   2   2   2   0
   0   2   2   2   2   0
   0   2   2   2   2   0
   0   0   0   0   0   0

octave:5> x = y(2:rows(x)+1, 2:columns(x)+1)
x =

   2   2   2   2
   2   2   2   2
   2   2   2   2