[vtkusers] How to render the contours of a binary image?

[Thomas Kilgus]

Hi,

I solved my issue. It wasn't about the data type but I was still 
applying a texture to the mapper.

However, the vtkMarchingSquares - which is meant for image data - 
generates not the kind of contours I am looking for. I would like to 
render the edges of the image pixels. The filter interpolates the edges 
at corners. Is there any out the box way to render the edges of the 
pixels and make it look "stepped"?

Regards
Thomas

On 10.06.2011 11:43, Thomas Kilgus wrote:
> Hi,
>
> I figured out that I should use the the output of the vtkMarchingSquares
> filter as input for the mapper. Furthmore, my data type of the
> vtkImageData is actually char which seems to disturb the filter. How can
> I apply such a filter on a char vtkImageData? Do I have to convert it first?
>
> regards
> thomas
>
>
> On 31.05.2011 16:29, Bill Lorensen wrote:
>> Try,
>> contourFilter->GenerateValues(1, .5, .5);
>>
>> On Tue, May 31, 2011 at 8:57 AM, Thomas Kilgus
>> <t.kilgus at dkfz-heidelberg.de>   wrote:
>>> hinHi Dominik,
>>>
>>> the documentation of vtkDiscreteMarchingCubes tells me that I should use
>>> vtkMarchingSquares for 2D image slices (which i have in my case).
>>> vtkDiscreteMarchingCubes is not applicable for data with dimension != 3. If
>>> I use vtkMarchingSquares instead the following message occurs:
>>> "vtkPainterPolyDataMapper: Mapper has no input" and my image is still
>>> completely rendered in one color.
>>>
>>> regards
>>> thomas
>>>
>>> On 31.05.2011 13:24, Dominik Szczerba wrote:
>>>> See vtkDiscreteMarchingCubes.
>>>> What I also do at times is to cast the binary image to float, smooth
>>>> it, and then extract 0.5 value.
>>>>
>>>> On Tue, May 31, 2011 at 1:19 PM, Thomas Kilgus
>>>> <t.kilgus at dkfz-heidelberg.de>     wrote:
>>>>> Hi,
>>>>>
>>>>> I am using a vtkPolyDataMapper to render images as a texture on a plane.
>>>>> Some images (in the form of vtkImageData) just consist of the values 1.0
>>>>> and
>>>>> 0.0. By means of a vtkLookuptable I can easily render those images with a
>>>>> single color (the 1.0 values) and with a transparent background (0.0
>>>>> values). What would be the best way to render just the contours of those
>>>>> images?
>>>>>
>>>>> I already found the vtkContourFilter. But when I use it like this:
>>>>>
>>>>>        vtkSmartPointer<vtkContourFilter>     contourFilter =
>>>>> vtkSmartPointer<vtkContourFilter>::New();
>>>>>        contourFilter->SetInput(image);
>>>>>        contourFilter->GenerateValues(1, 1.0, 1.0);
>>>>>        contourFilter->Update();
>>>>>        texture->SetInputConnection(contourFilter->GetOutputPort());
>>>>>
>>>>> the whole image is just rendered as a single color.
>>>>>
>>>>> Is there anything wrong with my code or is the vtkContourFilter just not
>>>>> the
>>>>> appropriate filter for my task?
>>>>>
>>>>> regards
>>>>> thomas kilgus
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