Size scale limitation when trying to import an image

Provides a system for patient-specific cardiovascular modeling and simulation.
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mehrdad roustaei
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Joined: Wed Oct 03, 2018 10:40 pm

Size scale limitation when trying to import an image

Post by mehrdad roustaei » Mon Jul 08, 2019 5:26 pm

Hi, there is a minimum limitation of 0.001 for the images when I try to import them into Simvascular. But the images I have in some cases are smaller than that. Plus, there is a single value that we can enter for the scale; however, in many cases there is an difference in the resolution of the third direction of the image.
I have segmented my image using the 0.001 scale factor already. Is there a way to convert the segmentation that I already have to an smaller scale? Re-segmenting the data is not really an option for me since it is so time-consuming and I am thinking about using the similarity (i.e. keeping the Re the same by scaling the inlet velocity instead of the geometry) to convert my results at the end to the right values. It would be really helpful if I could use another option to solve the right model in the beginning.
Thank you!

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David Parker
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Joined: Tue Aug 23, 2005 2:43 pm

Re: Size scale limitation when trying to import an image

Post by David Parker » Wed Jul 10, 2019 11:58 am

Hi Mehrdad,

I could add the capability to decrease the scale factor if that is what you need, no reason to restrict it I think. I don't think it is possible to add direction-dependent scaling, not supported by the MITK framework we are using.

Scaling the segmentation would be a bit involved, they are stored in an XML format and you would need to convert all of the coordinate values, there are several sections (e.g. path_point, control_points, contour_points). You could write a Python script to do this using the ElementTree package (https://docs.python.org/2/library/xml.e ... ttree.html) to read/traverse/write the segmentation XML files.

It would probably be easier to create the model and mesh it, and then scale the mesh files coordinates, could use VTK to do that.

Cheers,
Dave

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