[vtkusers] Image coords and image transformation

[Jothybasu Selvaraj]

Converting from world to pixel coordinates is trivial ( vice versa)

Have a look at this

http://devsample.org/index.php?option=com_content&task=view&id=48&Itemid=27

Jothy

On Mon, May 21, 2012 at 11:54 PM, Fabian Torres <fabian.trobles at gmail.com>wrote:

> Hi  Jothy
>
> Thanks for your reply.
>
> I have already checked the worldPointPicker class and it does not solve my
> problem, cause it only give me the world coordinate, and as I said
> previously I already know that. What I want to know is the index of the
> pixel (to obtain the value of that pixel) that is located in that world
> coordinate.
>
> Manipulating the camera its not an option because I´m  working with a lot
> of images and a lot of points and I´m not picking the point manually. So a
> think that would not solve my problem.
>
> Thanks for your advice,
> If you, or somebody else, have some other suggestion I would be please to
> hear about it.
>
>
>
> On Mon, May 21, 2012 at 3:14 PM, Jothybasu Selvaraj <jothybasu at gmail.com>wrote:
>
>> You could use vtkWorldPointPicker to do that. But I am afraid that it
>> would give you the correct coordinate, since you are transforming your
>> actor.
>>
>> Rather I would suggest you to manipulate the camera and use the
>> worldPointPicker.
>>
>>
>> Jothy
>>
>> On Mon, May 21, 2012 at 9:06 PM, Fabian Torres <fabian.trobles at gmail.com>wrote:
>>
>>> Hi.
>>>
>>> I would try to explain my problem the best I can.
>>>
>>> I have some ultrasound images that have certain position, orientation
>>> and scale in a world space coordinate.
>>>
>>> To display each image in vtk scene I have used vtkTransform in the
>>> vtkImageActor for each image:
>>>
>>> actor->SetInput(image);
>>> actor->SetTransform(transform);
>>>
>>>
>>> I´m able to display the images in the correct position and orientation
>>> in the vtk scene. This has not been a problem.
>>>
>>> Now, the problem I have is that I want to access the vtkImageData from
>>> its world space coordinate, not the image coords.
>>>
>>> Example if I want to access the pixel (0,0,0) image coords meaning the
>>> first pixel of the imageData, and I know that this pixel is located in
>>> the coordinate (100,130,89) in the world space. How can I access to the
>>> data of this pixel using the world space coordinates?  Can I access
>>> the imageData from the actor?
>>>
>>> --
>>> Fabián Torres Robles
>>> Maestria en Ciencias en Ingeniería Electrónica
>>> Ingeniería en Sistemas Electrónicos
>>> tel. 58081280, 0445534661338
>>> e-mail fabian.trobles at gmail.com, dae.wong at gmail.com
>>>
>>>
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>>
>>
>> --
>> Jothy
>>
>>
>
>
> --
> Fabián Torres Robles
> Maestria en Ciencias en Ingeniería Electrónica
> Ingeniería en Sistemas Electrónicos
> tel. 58081280, 0445534661338
> e-mail fabian.trobles at gmail.com, dae.wong at gmail.com
>
>


-- 
Jothy
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