[Insight-developers] Re: [inbox] Re: BlobSpatialObject

[Stephen R. Aylward]

To pick on me you must try much harder than that :)   I wasn't feeling 
picked-on at all!

I like the idea of adding more to the book - there is a ton more to be 
said; time was the limiting factor...

Thanks,
Stephen

Will Schroeder wrote:

> Hi Stephen-
> 
> Thanks, that answered the question. Even though the software guide is 
> 550 pages, there is still a lot of room for more explanation. I think 
> next year we'll make another pass and try to add more text (like the 
> text you just sent) to the book. BTW- I am not picking on you, most all 
> of the material is a bit sparse.
> 
> Will
> 
> At 12:50 PM 8/13/2003 -0400, Stephen R. Aylward wrote:
> 
>> BlobSpatialObjects are defined by a list of points in index space (the 
>> points occupy (e.g., measure) a volume of physical space and the size 
>> of that volume is determined by a "spacing" transform - like 
>> points/indexes in an image).
>>
>> To test isinside for a worldpoint, it does a worldToIndex transform, 
>> and then sees if the resulting indexpoint is within 0.5 index units 
>> (using independent city-block distance measures) of any point/index in 
>> the list that defines the blob spatial object.
>>
>> BUT, your question pointed out a bug in the IsInside function - I just 
>> checked in a fix.   It was actually doing a very funky (aka wrong) 
>> distance from index test.   THANKS!
>>
>> Does this answer your question?  Seem valid?
>>
>> Thanks,
>> Stephen
>>
>> Will Schroeder wrote:
>>
>>> Hey Stephen-
>>> Is the BlobSpatialObject assumed to be a convex set of points? What 
>>> does it mean to be inside a blob (defined by points)?
>>> Will
>>>
>>
>> -- 
>> ===========================================================
>> Dr. Stephen R. Aylward
>> Associate Professor of Radiology
>> Adjunct Associate Professor of Computer Science and Surgery
>> http://caddlab . rad . unc . edu
>> aylward at unc . edu
>> (919) 966-9695
> 
> 

-- 
===========================================================
Dr. Stephen R. Aylward
Associate Professor of Radiology
Adjunct Associate Professor of Computer Science and Surgery
http://caddlab . rad . unc . edu
aylward at unc . edu
(919) 966-9695