[vtkusers] Sobel Filter

[Sergio Vera]

Hi,
you can use vtkImageGradientMagnitude<http://www.vtk.org/doc/release/5.4/html/a00771.html>too

regards.

Sergio

On Tue, Feb 9, 2010 at 4:02 PM, Jérôme <jerome.velut at gmail.com> wrote:

> Hi,
> Sobel filter has several components in its output because it computes a
> gradient
> separately for x and y. You can use vtkImageMagnitude after your sobel to
> get
> only one component. This way, you can re-compute the sobel.
>
> HTH
> Jerome
>
> 2010/2/9 circass <circass at gmail.com>
>
>
>> Hi David, thanx for your answer,
>>
>> Actually i m trying to make an edge detection operation and i want to make
>> it repeatetly.
>>
>> I searched for it and find sobel Filter. is there any other filter you can
>> advice me ?
>>
>> Thanx,
>> Circass
>>
>>
>> David Doria-2 wrote:
>> >
>> > On Tue, Feb 9, 2010 at 8:53 AM, circass <circass at gmail.com> wrote:
>> >
>> >>
>> >> Hi my friends,
>> >> i m trying to use sobel filter, it works at the first time but when i
>> try
>> >> to
>> >> make a second filtering on filtered image it gives me an error about
>> >> scalar
>> >> component number. it says it can work with only one scalar component.
>> >>
>> >> Thanx, Circass.
>> >>
>> >>
>> > The problem is that vtkImageSobel2D produces a vector image:
>> >
>> > vtkImageSobel2D <classvtkImageSobel2D.html> computes a vector field from
>> a
>> > scalar field by using Sobel functions. The number of vector components
>> is
>> > 2
>> > because the input is an image. Output is always doubles.
>> >
>> > This "image" has a vector (more than one component) at each "pixel".
>> This
>> > is
>> > why you can't filter it again. I actually don't understand though, I
>> > thought
>> > the Sobel filter just multiplied a mask such as
>> >
>> > 1 0 1
>> > 2 0 2
>> > 1 0 1
>> >
>> > at each pixel to come up with a scalar at each pixel?
>> >
>> > Thanks,
>> >
>> > David
>> >
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>> --
>> View this message in context:
>> http://old.nabble.com/Sobel-Filter-tp27515510p27515819.html
>> Sent from the VTK - Users mailing list archive at Nabble.com.
>>
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