[Insight-users] questions about spatial objects & line extraction

[Dan Mueller]

Hi Judith,

Welcome to ITK!

I don't think the SpatialObject component of ITK will help you with
line/circle extraction. From my understanding, there are three main
uses for spatial objects:
  1. Input/output: MetaIO supports reading and writing SpatialObjects
  2. Rendering via a scene graph: see http://www.vtk.org/Wiki/SOViewer
  3. Registration: see Code/Algorithms/itkImageToSpatialObjectMetric.h

Instead you might consider using the Hough Transform:
    http://www.itk.org/Doxygen/html/classitk_1_1HoughTransform2DLinesImageFilter.html
    http://www.itk.org/Doxygen/html/classitk_1_1HoughTransform2DCirclesImageFilter.html

There are some examples included with ITK:
    Examples\Segmentation\HoughTransform2DLinesImageFilter.cxx
    Examples\Segmentation\HoughTransform2DCirclesImageFilter.cxx

Perhaps you might also be interested in OTB, a toolbox built on top of
ITK for remote sensing image processing:
    http://otb.cnes.fr

I am not involved in this project, nor have I used it, but I have
noticed they have some extensions for line detection (mainly for roads
from satellite images).

Hope this helps.

Regards, Dan

2008/11/21 juhaas <juhaas at uni-koblenz.de>:
> hey everyone,
>
> i´m still new and i still have some problems. could please anybody help me?
>
> in need to extract lines (straight and circled lines) from an image of a
> domino tile. so far, i did some preprocessing and the sobel edge detection.
> after that i binarized the image and did a line thinning. so now i have a
> binary image with the contours of a rectangle and circles.
>
> what i want to do now is to extract these lines. i thought i could maybe use
> the SpatialObject classes or the ChainCodePath. but i have no clue how i
> could get my lines from the image into a SpatialObject or ChainCode data
> structure.
>
> to be honest i don´t understand the use of the SpatialObject at all. is this
> class actually useful to stor segmentation results like this? or can you
> only create some "artificial" models of simple objects?
>
> i feel really lost right now in this huge library.
>
> thanks for any help,
> judith
>
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