[Insight-users] Distance to point in connected object

[Dan Mueller]

Hi Kevin,

Assuming your image is binary (either 'on', or 'off'), I think the 
FastMarchingImageFilter will do this for you: 
http://www.itk.org/Doxygen/html/classitk_1_1FastMarchingImageFilter.html

Create a speed image from your binary image (off = 0.0, on = 1.0), add a 
trial point at the desired location, and run the filter. The result will 
be the time-crossing map (note that all values outside of the speed 
image (0.0) will receive a huge value, so you will have to do a 
threshold at the end). The FastMarchingImageFilter is also in the 
software guide around section 9.3.1.

HTH, Dan


Kevin H. Hobbs wrote:
> Is there any way to tell how far the pixels of an object are from a
> point within that object without the path leaving the object? I don't
> mean "as the crow flies" but following roads.
>
> I know that's a sort of a bad description maybe some ASCII art will
> help.
>
> If I have a segmented image like this.
>
> -------------------
> |                 |
> |         11      |
> |          1      |
> |    111   1      |
> |   11111111111   |
> |    111          |
> |                 |
> -------------------
>
> I pick a point in the middle of the blob in the lower left. I want the
> pixels relabeled like this.
> -------------------
> |                 |
> |         98      |
> |          7      |
> |    212   6      |
> |   21012345678   |
> |    212          |
> |                 |
> -------------------
>   
> ------------------------------------------------------------------------
>
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>   

-- 
Dan Mueller
PhD Candidate (02562065)
School of Engineering Systems (ES)
Faculty of Built Environment and Engineering (BEE)
Queensland University of Technology (QUT)
CRICOS No: 00213J

Email: d.mueller at qut.edu.au
Phone: +617 3864 9124
Mobile: +61 0401 451 850
Room: Gardens Point S903.10
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