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From: Robbie Janssen on 6 May 2008 05:46
I still don't get the same result Yumnam. I am using Matlab
release 7.5.0(R2007b), it should be a strange thing but
maybe there's where the error is? I've posted a picture at
http://www.student.tue.nl/t/r.j.m.janssen/FILTERS.jpg

The kernel (or mask) is defined as [0 -1; 1 0]

Can you maybe take a look at it and explain why there's
still a difference?

Regards,

Robbie

Yumnam Kirani Singh <kirani.singh(a)gmail.com> wrote in
message
<30971887.1199861291430.JavaMail.jakarta(a)nitrogen.mathforum.
org>...
> Sorry, I have made a mistake in the explanation of
filter2 and conv2. The two are equivalent under the
following cases.
> >>xf=filter2(fliplr(mask),x); % using as conv2
> >>xc=conv2(x,mask, 'same');
> then xc and xf are the same.
> In the other way,
> >>xc=conv2(x,fliplr(mask), 'same'); % using as filter2
> >>xf=filter2(mask,x);
> here also, xc and xf will give the same result.

From: Robbie Janssen on 6 May 2008 06:01
Got it, you should (at least not in my Matlab version)
transpose the mask instead of just flipping it from left to
right. See matlab-help for filter2

"Robbie Janssen" <r.j.m.janssen(a)student.tue.nl> wrote in
message <fvp9cr$1ca$1(a)fred.mathworks.com>...
> I still don't get the same result Yumnam. I am using
Matlab
> release 7.5.0(R2007b), it should be a strange thing but
> maybe there's where the error is? I've posted a picture
at
> http://www.student.tue.nl/t/r.j.m.janssen/FILTERS.jpg
>
> The kernel (or mask) is defined as [0 -1; 1 0]
>
> Can you maybe take a look at it and explain why there's
> still a difference?
>
> Regards,
>
> Robbie
>
> Yumnam Kirani Singh <kirani.singh(a)gmail.com> wrote in
> message
>
<30971887.1199861291430.JavaMail.jakarta(a)nitrogen.mathforum.
> org>...
> > Sorry, I have made a mistake in the explanation of
> filter2 and conv2. The two are equivalent under the
> following cases.
> > >>xf=filter2(fliplr(mask),x); % using as conv2
> > >>xc=conv2(x,mask, 'same');
> > then xc and xf are the same.
> > In the other way,
> > >>xc=conv2(x,fliplr(mask), 'same'); % using as filter2
> > >>xf=filter2(mask,x);
> > here also, xc and xf will give the same result.
>

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