[Insight-users] Volume overlay
Sara Rolfe
smrolfe at u.washington.edu
Thu Feb 10 16:49:39 EST 2011
The labels image has unsigned chars between 0-4. I implemented the
iterator like you suggested, and now the value range is correct.
However, the display looks incorrect. I am thinking that it may be a
VTK issue now.
On Feb 10, 2011, at 1:29 PM, robert tamburo wrote:
> What's the value of your label? In your previous code, the output of
> the add filter is set to unsigned char, so you may have typecasting
> issues as David alluded to.
>
> Your current code looks okay to me. Try writing bwImage to disk to
> determine if there is an ITK or VTK issue.
>
>
> On Thu, Feb 10, 2011 at 3:15 PM, Sara Rolfe
> <smrolfe at u.washington.edu> wrote:
> I'm attaching my code. The rescale intensity filter worked great to
> get the image data in the right right range. But I'm still having a
> problem when I try to add the regions which will be labeled with
> color. I move the data into the intensity range 100-200, and then
> use the add image filter to add the labeled image on top, so that I
> can use a piecewise colormap in VTK to apply colors to these
> values. I think the add images may be where the problem is. What I
> would rather do is mask the image with the labels so that the pixels
> in the image were replaced with the label value for all non-zero
> labels. Is there anything like this implemented, or would I need to
> go through pixel by pixel and change the values? I've only seen
> binary mask filters.
>
> Thanks,
> Sara
>
>
>
>
> On Feb 10, 2011, at 10:56 AM, David Doria wrote:
>
>> On Thu, Feb 10, 2011 at 1:38 PM, Sara Rolfe
>> <smrolfe at u.washington.edu> wrote:
>> Hello,
>>
>> I'm attempting to overlay an image with color. I've had trouble
>> finding documentation on this, either in ITK or VTK. The way I'm
>> going about it is to scale the values of the image down and then
>> use the add image filter to add the labels on top. I could then
>> use VTK to create a corresponding colormap.
>>
>> However, I'm getting stuck on something that should be very
>> simple. My operations to combine the two images are failing. I
>> think the problem is the SubtractConstantFromImageFilter. I've
>> checked the output and it looks like the constant is not being
>> subtracted. The input to this filter is an image with a value of 0
>> for the background and 255 for the object. I'd like to change
>> these to 0 and 1. The pixel type is unsigned char. I use the
>> following:
>>
>> SubFilterType::Pointer subFilter = SubFilterType::New();
>> InputPixelType subValue = 254;
>> subFilter->SetConstant(subValue);
>> subFilter->SetInput( imageInverter->GetOutput() );
>> subFilter->Update();
>>
>> But the output image is still 0 - 255. Am I missing something
>> simple?
>>
>> Also, is there a better way to accomplish this task, or any
>> examples showing something similar?
>>
>> Thanks,
>> Sara
>>
>> Can you provide a compilable code snippet? I'm also not sure what
>> you mean by "overlay with color"?
>>
>> Something that jumps out is that if you subtract 254 from an
>> unsigned char you will be assigning a negative value to an unsigned
>> char which is undefined.
>>
>> If all you are trying to do is map (0-255) to (0-1) you could use
>> itkRescaleIntensityImageFilter
>> http://www.itk.org/Wiki/ITK/Examples/ImageProcessing/RescaleIntensityImageFilter
>>
>> David
>
>
> _____________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://www.kitware.com/products/protraining.html
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20110210/f266c7eb/attachment.htm>
More information about the Insight-users
mailing list