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Re: Summed Area Table / Integral Image

• To: mathgroup at smc.vnet.net
• Subject: [mg115413] Re: Summed Area Table / Integral Image
• From: Peter Pein <petsie at dordos.net>
• Date: Mon, 10 Jan 2011 02:39:44 -0500 (EST)
• References: <igbng6$hfs$1@smc.vnet.net>

On 09.01.2011 08:18, Gareth Edwards wrote:
> Next newbie question....
>
> Suppose I have a 2D matrix, what would be a neat syntax for computed the
> 'Integral Image' or summed area table? (
> http://en.wikipedia.org/wiki/Summed_area_table )
>
> Many thanks in advance for any neat suggestions.
>
> Best,
>
> Gareth
>


Hi Gareth,

  if I understand the article correctly,

In[1]:= sat[m_]:=Map[Accumulate,m,{0,1}]

should do what you want

In[2]:= TableForm@sat@ConstantArray[1,{5,3}]
Out[2]//TableForm=
1	2	3
2	4	6
3	6	9
4	8	12
5	10	15


Cheers,

  Peter