Matlab“按比例缩小"一个带有平均值的向量 [英] Matlab "Scale Down" a Vector with Averages

问题描述

很难解释我要寻找的东西，我在Matlab中用n矩阵表示了一个图像，并且试图将其按比例缩小到4x4，就像对图像进行缩放(平均最近的值)一样

Quite hard to explain what I am looking for, I have an image represented as a m by n matrix in Matlab and I am trying to scale it down to 4x4 the same way an image would be scaled (average the nearest values)

例如

1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
0 2 3 4 9 9 7 8
0 2 3 4 9 9 7 8
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 7
1 2 3 4 5 6 7 7

将成为

1.5 3.5 5.5 7.5
1.0 3.5 9.0 7.5
1.5 3.5 5.5 7.5
1.5 3.5 5.5 7.0

推荐答案

看起来像imresize所提供的内容与您的预期略有不同.对于您的输入数据，将执行以下操作:

Looks like imresize gives something slightly different from what you expected. For your input data, the following will work:

A = filter2([1 1; 1 1] / 4, X, 'same')
A = A(1:2:end, 1:2:end);

编辑:实际上，执行以下操作可能会更快:

EDIT: Actually, it's probably faster to do the following:

i = 1:2:size(A,1)-1;
j = 1:2:size(A,2)-1;

B = 0.25 * (A(i,j) + A(i+1,j) + A(i,j+1) + A(i+1,j+1));

这篇关于Matlab“按比例缩小"一个带有平均值的向量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！