Re: when should I pad image before filtering?
From: Martin Leese (please_at_see.Web.for.e-mail.INVALID)
Date: 03/28/05
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- In reply to: lucy: "Re: when should I pad image before filtering?"
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Date: Sun, 27 Mar 2005 17:33:58 -0700 To: lucy <losemind@yahoo.com>
lucy wrote:
> "lucy" <losemind@yahoo.com> wrote in message
> news:d20avh$p2b$1@news.Stanford.EDU...
>
>>I am always confused by the padding for image filtering.
>>
>>I have an 270x230 "image" and is to be filtered with a 250x250 "filter".
The bit in the middle is almost correct. The rest
of the output image will be wrong. Whether this is
a problem for you depends on why you are doing this.
...
>>When do we choose which option?
They are all wrong. You use the one which is least
wrong, and which that is depends on your input image
and what you seek to achieve with it.
> Strange. I really don't understand this:
>
> what happens if I have a 270x230 image convolved with a
> 600x600 filter using Matlab function?
Try it and see.
> what happens if I have a 270x230 image convolved with a 100 x 100 filter
> using the same matlab function?
Try it and see.
> Are these results still correct?
"Still" correct; what makes you think any of this
is correct?
> I understand the small case: if an image 270x230 convolved with a 3x3
> filter, I understand, the image will have false values on its 4 side 1pixel
> width boundary. All other values should be correct value...
Yep. The large filter case is no different (except
that it is larger).
Regards,
Martin
-- Regards, Martin Leese E-mail: please@see.Web.for.e-mail.INVALID Web: http://members.tripod.com/martin_leese/
- Previous message: Duke: "Geophysical images"
- In reply to: lucy: "Re: when should I pad image before filtering?"
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