[IGSTK-Users] How to get the ImageSpatialObject from an ImageSpatialObjectRepresentation

[Luis Ibanez]

Hi Vincent,


Thanks for pointing this out.


What we are planning to do here is the following:

1) Views, in response to picking events will throw
    IGSTK PointEvents, that will contain both a Point
    and a reference to a coordinate system (the one
    of the View).

2) You will be able to request the Transform between
    the View CoordinateSystem and the ImageSpatialObject
    pixel data coordinate system.

3) With the Transform you will get from (2), you will
    be able to convert the point from the View coordinate
    system to the ImageSpatialObject pixel data coordinate
    system

4) Once you have the point in image space, you will be
    able to map it to pixel indices and access (read only)
    pixel data.


Pieces (1),(3) and (4) need to be implemented.
Piece (2) is currently functional


Could you please log a bug, for this topic ?

You could describe it as "fixing the coordinate system
framework for picking events".

... or something along those lines...


BTW: Breaking the encapsulation of the ImageObjectRepresentation
      is probably not the best way to solve this issue.



    Thanks


       Luis



---------------------
Vincent Gratsac wrote:
> Hi all,
> 
> First of all, thanks for the great effort of the IGSTK team to bring us 
> this new release !
> 
> I did not receive any answer to my last mail about how to get the 
> ImageSpatialObject from an ImageObjectRepresentation.
> 
> Did you understand my problem, and do you think that adding a 
> RequestGetImageSpatialObject() method to the ImageObjectRepresentation 
> class would be possible ?
> 
> Vincent
> 
>> Hi all,
>>
>> I'm currently working on slicing of displayed objects by giving a 
>> picked point.
>> The NeedleBiopsy example is helpful to learn how to do that !
>> Here is my problem : my software can display some 
>> ObjectRepresentations for more than one SpatialObjects, but I'm not 
>> able to know to which ImageSpatialObject an 
>> ImageSpatialObjectRepresentation is related.
>>
>> This is a problem when we try to convert a physical point to image 
>> indexes ( that's why I submitted the idea to add a 
>> ResliceToPhysicalPoint method in the ImageSpatialObjectRepresentation 
>> class).
>>
>> This is also a problem if the transformation between one of the 
>> ImageSpatialObjects and the View object differs from Identity. In this 
>> case, I need to get this transformation and multiply its inverse to 
>> the picked point's coordinates, in order to express the picked point's 
>> coordinates in the ImageSpatialObject coordinate system. Next, I will 
>> have to convert the physical point to image index.
>>
>> To conclude, I found some cases in which getting the 
>> ImageSpatialObject from an ImageSpatialObjectRepresentation is very 
>> useful. Is there a way to do it , or would it be unsafe to add such a 
>> method ?
>>
>> Vincent
> 
>