# How to get output of HoughTransform2DLinesImageFilter() ?
**URL:** https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059
**Category:** Beginner Questions
**Tags:** python
**Created:** [April 22, 2021, 12:58pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059 "2021-04-22T12:58:15Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@YMarth](https://discourse.itk.org/u/YMarth)
#### Post date: [April 22, 2021, 12:58pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/1 "2021-04-22T12:58:15Z")
I am trying to use Hough Lines transform on some iage with itk on python (spyder).
I used the given example here:
[How to deal with HoughTransform2DLinesImageFilter GetLines() method in python - Beginner Questions - ITK](https://discourse.itk.org/t/how-to-deal-with-houghtransform2dlinesimagefilter-getlines-method-in-python/1861)
but I have the same problem. Here the code to make reading easier:
##Houghlines##
edges = sobslice #image itk.image(itk.F,2)
houghF = itk.HoughTransform2DLinesImageFilter[itk.F, itk.F].New()
houghF.SetInput(edges)
houghF.SetAngleResolution(100)
houghF.SetNumberOfLines(2)
houghF.Update()
DetectedLines=houghF.GetLines()
print(DetectedLines[0].GetPoints())
##
DetectedLines is a “Swig object of type std::vector” from which I can’t access data. At least, I know its size (with len() or .size()) but I can’t access value with GetPoint().
Any idea ?
Thanks !
---
### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [April 22, 2021, 3:55pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/2 "2021-04-22T15:55:22Z")
Does `DetectedLines[0].GetPoints()[0]` work?
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### Author:  [@YMarth](https://discourse.itk.org/u/YMarth)
#### Post date: [April 23, 2021, 7:46am UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/3 "2021-04-23T07:46:06Z")
> [@dzenanz](#):
>
> `DetectedLines[0].GetPoints()[0]`
Unfortunately no, I still have a ‘proxy of a swig object’ and not a value.
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### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [April 23, 2021, 1:27pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/4 "2021-04-23T13:27:56Z")
Does `DetectedLines[0].GetPoint(0)` work? `DetectedLines[0]` is a [LineSpatialObject](https://itk.org/Doxygen/html/classitk_1_1LineSpatialObject.html).
@nick did you get it working, and how?
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### Author:  [@YMarth](https://discourse.itk.org/u/YMarth)
#### Post date: [April 23, 2021, 3:34pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/5 "2021-04-23T15:34:10Z")
Neither,it gives the same kind of output that .GetPoints(). I would expect an array with some coordinate, an angle and a distance as it is what the Hough transform should compute.
I read the page you linked with LineSpatialObject. The method “PrintSelf()” is not working (error), may be it coul be a way to retrieve the value ?
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### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [April 23, 2021, 3:35pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/6 "2021-04-23T15:35:27Z")
Maybe `print(DetectedLines[0])`?
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### Author:  [@YMarth](https://discourse.itk.org/u/YMarth)
#### Post date: [April 23, 2021, 3:51pm UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/7 "2021-04-23T15:51:11Z")
Thought I already tried this one but may be I only tried “print(DetectedLines)” and “print(DetectedLines[0].GetPoints)”.
It gives something at least, some info on the object (size) plus some on the region but I don’t know which region ! I have also info on “Family Bounding Boxes of Spatial Object”. I don’t see something which looks like a couple (distance, angle).[Output\_printDetectedLines.txt](https://discourse.itk.org/uploads/short-url/w7SZzUpbcVCgS54NJeKMJInE5Th.txt) (3.8 KB)
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### Author:  [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)
#### Post date: [May 4, 2021, 3:00am UTC](https://discourse.itk.org/t/how-to-get-output-of-houghtransform2dlinesimagefilter/4059/8 "2021-05-04T03:00:51Z")
To get the [LineSpatialObjectPoint](https://itk.org/Doxygen/html/classitk_1_1LineSpatialObjectPoint.html):
```auto
point = DetectedLines[0].GetPoint(0)
```
This has methods:
```auto
print(point.GetPositionInObjectSpace())
print(point.GetPositionInWorldSpace())
print(point.GetNormalInObjectSpace(0))
```