[Insight-users] Filtering region by region an image

[Mathieu Malaterre]

David,
	Thank you for your answer. Could you please have a look at this piece 
of code and tell where I am wrong.


	//define region
	InputImageType::RegionType region;
	InputImageType::SizeType size;
	InputImageType::IndexType index;
	
	index[0] = index[1] = 50;
	size[0] = size[1] = 50;
	region.SetSize(size);
	region.SetIndex(index);

	//ITK pipeline
	filter->SetInput(reader->GetOutput());
	writer->SetInput(filter->GetOutput());

	reader->GetOutput()->SetRegions(region);
	reader->GetOutput()->Allocate();

	writer->Update();

I also try:

	[snip]
	//ITK pipeline
	reader->GetOutput()->SetLargestPossibleRegion( region );
	reader->GetOutput()->SetBufferedRegion( region );
	reader->GetOutput()->SetRequestedRegion( region );
	reader->GetOutput()->Allocate();

	writer->Update();




In both case, the filter works on the *whole* image and not only the 
region I want.

Again here is what I want:
A is the image I read from file (FileReader) but I want to process 
*only* the subregion B of this image and then write back an image of 
same dimension as A but with the subregion B filtered.


-----------------------------------
| A                               |
|                                 |
|                                 |
|                                 |
|                                 |
|       -----------------         |
|       |               |         |
|       |      B        |         |
|       |               |         |
|       -----------------         |
|                                 |
-----------------------------------

And I really don't think it should be complicated, but I haven't been 
able to find any example in ITK Exemple tree (nor in 
ItkSoftwareGuide.pdf) that shows the pipeline to set up in order to do this.



As suggested by James Miller I could have use: StreamingImageFilter but 
this filter looks terribly complicated for my purpose. The region B is 
not necesseraly centered. And I don't want to process the whole image. 
In the near future I would like to process differents parts (not only 
just one) of my image but I don't want to process it *all*.

For example (A is still the initial image I read from file). And I would 
like to filter region B, C, D, E and then write backk the image 
generated (again the dimension should be the same as A, that's why I 
can't use ExtractImageFilter).

-----------------------------------
| A                               |
|                                 |
|   --------                      |
|   |  B   |         --------     |
|   --------         |   E  |     |
|       --------     --------     |
|       |  C   | --------         |
|       -------- |  D   |         |
|                --------         |
|                                 |
-----------------------------------

The only condition I could have here is that intersections between those 
pieces is NULL.

Does anyone know how to set this up ? Any help would REALLY be appreciated.


Thanks,
mathieu
Ps: I should really give aalib a try ;)



David Holmes wrote:
> Mathieu-
> 
> I think that you also could use the RequestedRegion
> property (see other note).  In your case, you would
> have to determine if each of your regions combined
> with fully cover the entire image.
> 
> thanks
> 
> david 
> --- Mathieu Malaterre
> <Mathieu.Malaterre@creatis.insa-lyon.fr> wrote:
> 
>>Hi all,
>>
>>   I would like to know, how I can work on a region
>>of an image. I tried 
>>to do it with ExtractImageFilter but I fail to make
>>it work.
>>
>>   The output of the filter where of the size of the
>>extracted region 
>>(which is the way ExtractImageFilter is supposed to
>>work: decrease 
>>size), but I wanted it to be of size of the initial
>>image (= input of 
>>ExtractImageFilter)
>>
>>   Basically here is what I want to do. Let say I
>>have an image that I 
>>want to filter on 4 distinct parts (not necesseraly
>>identical).
>>
>>---------- ----------
>>|         |         |
>>|         |         |
>>|    1    |     2   |
>>|         |         |
>>---------- ----------
>>|         |         |
>>|         |         |
>>|    3    |     4   |
>>|         |         |
>>---------------------
>>
>>   Could someone give me the pipeline to use ? So
>>that at the end I have 
>>filtered the whole image (I don't know how to concat
>>images after having 
>>them extracted through ExtractImageFilter).
>>
>>   Should I use ImageRegion/ ImageRegionIterator/
>>ExtractImageFilter ?
>>
>>   Hoping to be clear,
>>
>>   Thank you,
>>   Mathieu Malaterre
>>
>>
>>-- 
>>Mathieu Malaterre
>>CREATIS
>>28 Avenue du Doyen LEPINE
>>B.P. Lyon-Montchat
>>69394 Lyon Cedex 03
>>http://www.creatis.insa-lyon.fr/~malaterre/
>>
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>>Insight-users@public.kitware.com
>>
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-- 
Mathieu Malaterre
CREATIS
28 Avenue du Doyen LEPINE
B.P. Lyon-Montchat
69394 Lyon Cedex 03
http://www.creatis.insa-lyon.fr/~malaterre/