[Insight-users] Smoothing an image by a sliding ball or paraboloid.

[Roman Grothausmann]

Dear Richard,

Richard Beare wrote:
> I've submitted a suite of parabolic morphology tools to the insight journal :
> 
> http://hdl.handle.net/1926/1370

I get redirected to http://ij.itk.org/midas/item/view/2280 and then it says:
You cannot access this item!

But I found it over the Insight Journal search:
http://www.insight-journal.org/browse/publication/228

It seems to be exactly what I'm looking for but reading Your 
contribution article I started to wonder:
How do You get from a 1D image (as in figure 1) to a 2D binary image 
(which consists of foreground pixel columns whose heights correspond to 
the intensity values of the 1D image pixels) so that You can perform the 
(2D) parabolic dilation?

Or asked differently:
For smoothing a 2D image a 3D-ball (or paraboloid) is rolled over the 
intensity profile which is a uneven 2D surface in 3D space. But if I 
look at GrayscaleDilateImageFilter it expects a structuring element in 
2D if the input is a 2D image. (And I'd say it's not the same result as 
rolling a 3D-ball over the intensity profile.)
So is there a pre-filter that would crate a 3D binary image (from my 2D 
grey image) on which I could apply the BinaryDilateImageFilter with a 
ball structuring element? (And then a filter to convert this 3D binary 
image back to a 2D grey image?)

Many thanks again.
Roman



> be sure to fetch the latest version from the repository referenced in the paper.
> 
> On 4/22/10, Roman Grothausmann <roman.grothausmann at helmholtz-berlin.de> wrote:
>> Dear mailing list members,
>>
>>
>> To prevent a gradient decent filter from stopping at an insignificant
>> local minimum I'd like a ball of some radius to roll over the intensity
>> profile of an image. The result I'm interested in is the trace of the
>> ball (or paraboloid) centre while the ball is rolling.
>> I think this is equivalent to smoothing the image with such a rolling
>> ball filter as this ImageJ filter:
>>
>> http://rsbweb.nih.gov/ij/docs/menus/process.html#background
>>
>> And then tracing the gradient decent as is done in the Random access
>> iteration example in the user guide.
>>
>> So I wonder now is there a filter in ITK for image smoothing that works
>> by simulating a sliding ball or paraboloid like the imageJ filter?
>>
>> Any help is very much appreciated
>> Roman
>>

-- 
Roman Grothausmann

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