[Insight-users] How to create a set of spatially distributed images

[Gaetan Lehmann]

Hi,

Have you tried to generate your image with some itk::GaussianSpatialObject  
?

Regards,

Gaetan

On Mon, 08 Jan 2007 13:25:51 +0100, Christian Marshall Rieck  
<rieck at stud.ntnu.no> wrote:

>> Thanks for the reply, I am NOT avoiding the overlapping -- I just want
>> the particle-images to be overlapped naturally. That is, at each
>> overlapping region, the pixel values of one of the particle-images must
>> overwrite (NOT be added to) the pixel values of the other  
>> particle-image.
>> Pasting does the job, however, it also overwrites the black background  
>> of
>> each square-shaped particle-image (notice the square edges in the
>> overlapping areas in the sample
>> http://img81.imageshack.us/my.php?image=testyz7.png).
>
> In that case I dont know. Some guesses:
> *See if you can set the black border to a transparent color
> *Edit the pasting function to paste the pixels inside a cirle, leaving  
> out
> the black corners/borders of the little images
> *As you are outputing PNG-files, can you create an int[][] and save
> this to a PNG-file in software outside ITK? There must be libraries for
> this. In this case you can have a function to return one of your little
> images/circles in a 10x10 matrix and specify which pixels should be  
> copied
> to the array.
>
> Or you could wait until some of the nice people on this list with better
> programming skills than me answer your question :)
>
> chr.
>
>
>> > > I am trying to simulate an image like this:> > > >  
>> http://ftp.sv.vt.edu/pub/projects97/pvlachos/pvlachos_project/images/piv.gif>  
>> > > > I started with creating small sized GaussianImageSource instances  
>> and pasting them at random positions on a background using  
>> PasteImageFilter. The problem is when two GaussianImageSource overlap  
>> as it can be seen in thios sample:  
>> http://img81.imageshack.us/my.php?image=testyz7.png> > > > (2) If not,  
>> how to get rid of the ovelaping problem?> > First thing that fell into  
>> my head:> You could > instantiate an int/bool array[][] img with your  
>> image size. Everytime you > paste to some location (x,y) you set  
>> img[x][y] = 1/true. (also set all > pixels covered by this image). Next  
>> time you want to paste to the image > check the pixels you are going to  
>> paste into to se if there is an image > there alredy. If there is,  
>> choose a new one.> > As the number of places a new image fits in the  
>> larger image the > while(find_a_suitable_place) loop may take some  
>> time. I am sure you can > come up with something clever to speed this  
>> up.> > Example: > If your small images are 10x10 and you past to (0,0)  
>> you set > img[0..10][0..10] = 1. > If you try to paste the next small  
>> image to (2,2) (i guess you use a > random-function for this) you check  
>> img[2..12][2..12]. Since these are not > 0 you must search for a new  
>> location.> > Christian.>
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-- 
Gaëtan Lehmann
Biologie du Développement et de la Reproduction
INRA de Jouy-en-Josas (France)
tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
http://voxel.jouy.inra.fr