Re: How to downsample a image matrix using left and right downsampling
- To: mathgroup at smc.vnet.net
- Subject: [mg100924] Re: How to downsample a image matrix using left and right downsampling
- From: dh <dh at metrohm.com>
- Date: Thu, 18 Jun 2009 04:54:12 -0400 (EDT)
- References: <h19i7r$p7g$1@smc.vnet.net>
Hi,
what do you exactly mean by down sampling?
I assume that you want to take the mean of 4 times 4 blocks.
I first give a simpler example where we avarage 2 by 2 blocks:
=======================
a = Array[A, {4, 4}];
left = {{1, 1, 0, 0}, {0, 0, 1, 1}};
right = Transpose[left];
left.a.right/4
=======================
in your case left will be:
Table[If[0 < j - 4 (i - 1) < 5, 1, 0], {i, 25}, {j, 100}]
Daniel
tenveer wrote:
> HI all
>
> i am just stuck with a unique problem ...
>
> What i want is to downsample a matrix (image matrix) using two left
> and right matrices....
> e.g if i have a 100 by 100 image matrix X what i want is to downsample
> X to 25 by 25 matrix Y using two downsampling matrices U and V which
> are on left and right respectively i.e Y=U*X*V
>
> than what will the contents of the U and V matrices.
>
> Any help will be appreciated
>
>
>