[Insight-users] Image boundary solutions

[Matt McCormick]

Hi Jesse,

The ConfidenceConnectedImageFilter[1] or other region growing algorithms
described in the ITK Software Guide [2] will likely do what you desire.

Thanks,
Matt

[1]
http://www.itk.org/Doxygen/html/classitk_1_1ConfidenceConnectedImageFilter.html
[2] http://www.itk.org/ItkSoftwareGuide.pdf

Fri, Jun 7, 2013 at 8:08 AM, Jesse Ross-Jones <jesse.rj at gmail.com> wrote:

> Hi,
> So far I have not been able to find a function that does what the
> description describes. The closest was PadByRadius from ImageRegion,
> however this pads uniformly in any one dimension.
>
> Therefore I started to think about the steps necessary to recreate the
> method. This is what I have come up with so far, I would appreciate any
> feedback you might have.
>
> 0. Original image of the eye (original.im)
> 1. Threshold image to create binary image (binary.im) (0 =
> outside/background, 1 = inside field of view)
> 2. Dilate binary image by 1 pixel (dilated.im)
> 3. Subtract binary image from dilated image (dilated.im - binary.im) this
> creates a one pixel width boarder around the field of view FOV (boarder.im
> )
> 4. For every pixel (i) = 1 in the boarder image find the 8 neighborhood
> pixels in both the binary image (binary.im) and the original (original.im)
> and mutliply each corresponding neighborhood pixel together. This leaves
> only the grey-values of the pixels inside the FOV and removes the
> grey-values of the background.
> 5. Find the average of these multiplied 8 pixels and assign this average
> to the current pixel (i),
> 6. Repeat for remaining pixels inside the boarder
>
> The whole process is then repeated until a large enough boarder is created
> around the FOV of the eye.
>
> Can this be done more efficiently or simply?
>
> I look forward to thoughts on this,
> much appreciated,
> Jesse
>
>
> On Wed, Jun 5, 2013 at 1:19 PM, Jesse Ross-Jones <jesse.rj at gmail.com>wrote:
>
>> Dear ITK Users and Devs,
>>
>> I am working on vessel segmentation, using the STARE and DRIVE image
>> datasets, and in order to deal with the image boundary I am trying to
>> implement the following:
>>
>> The preprocessing algorithm starts with a region of interest
>> (ROI) determined by the camera’s aperture and iteratively grows
>> this ROI. Each step of the algorithm consists in the following.
>> First, the set of pixels of the exterior border of the ROI is de-
>> termined, i.e., pixels that are outside the ROI and are neighbors
>> (using four-neighborhood) to pixels inside it. Then, each pixel
>> value of this set is replaced with the mean value of its neighbors
>> (this time using eight-neighborhood) inside the ROI. Finally, the
>> ROI is expanded by inclusion of this altered set of pixels. This
>> process is repeated and can be seen as artificially increasing the
>> ROI, as shown in Fig. 1(b).
>>
>> from http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=01677727&tag=1
>>
>> Is there something similar already implemented? I am considering instead
>> to use the Wrap Pad Image Filter:
>> http://www.itk.org/Doxygen/html/classitk_1_1WrapPadImageFilter.html
>> to pad the region around the eye. Would this be a better possibility?
>>
>> Much Appreciated,
>> Jesse
>>
>>
>
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