[IGSTK-Developers] FW: error prediction in rigid body point based registration: comments from Jay West
David Gobbi
dgobbi at atamai.com
Thu Feb 9 16:20:29 EST 2006
Hi Kevin,
Jay provided a lot of good comments. I'll have a read through his 2004
paper that discusses transform composition and see what we might be able
to adapt to IGSTK.
- David
Kevin Cleary wrote:
> David and others:
>
> Here are some comments from Jay West at Accuray on the Wiki page. Jay
> is on my program committee at SPIE so I will see him this week and
> thank him for the comments.
>
> David, can you update the page at your convenience to reflect these
> comments? I am sure if you have some brief questions you can ask Jay
> West directly, but I doubt he has time for long discussions. But to me
> this is the beauty of open source as everything is open for
> discussion, comment, and improvement.
>
> Kevin
>
> ------------------------------------------------------------------------
>
> *From:* Jay West [mailto:jwest at accuray.com]
> *Sent:* Thursday, February 09, 2006 2:32 PM
> *To:* Kevin Cleary
> *Subject:* Re: error prediction in rigid body point based registration
>
> Hi Kevin,
>
>
> Sorry for the delay - as always, it's a struggle to find free time
> here at Accuray. Here are my comments on the Wiki page:
>
> Definitions: 1: "homologus" should read; homologous
>
> Definitions: 3: "homologus" should read; homologous
>
> Definitions: 4 should read something like "Expected target
> registration error: statistical expected value of TRE, derived from
> distributions based on theoretical derivations or past observation."
>
> Motivation: "root means square" should read; "root mean square".
> Possibly reference Sibson '79 paper for claim that FRE is independent
> of fiducial configuration.
>
> Motivation: "derived approximate expression" should read "derived an
> approximate expression"
>
> Motivation: last line - "function of target registration error" should
> read; "function of FLE".
>
> Motivation: last line - "the the fiducial points" should read; "the
> fiducial points"
>
> David's suggestion: I agree that it's important to handle the
> composition of transforms. There is no method of doing this specified
> in the suggestion - I suggest referencing the TMI paper on this by
> Calvin and me, published in 2004: "Designing optically tracked
> instruments for image-guided surgery", Jay B. West and Calvin R.
> Maurer, Jr., vol 23 (5), 533-545, May 2004.
>
> What information is needed to compute TRE: Assuming you're working in
> three dimensions, seems to be intuitive that whatever formulation you
> use, you need
>
>
> (a) The point at which you're calculating, in some arbitrary
> coordinate system (three parameters)
>
> (b) The principal axes of the fiducial configuration: the page claims
> this can be done with 3 parameters - I would use 6 (two vectors, the
> third being the cross product of the first two) for simplicity.
>
> (c) The centroid of the fiducial configuration (three parameters)
>
> (d) The value of the moments of the fiducial configuration about each
> axis (three parameters)
>
> Hence you need 12 parameters, including the three which are arguments
> to the computation function.
>
> The answer to (1) is that yes, all rigid body registration errors can
> be described with the same basic formulations, assuming obviously that
> you're subject to the restrictions and happy with the assumptions made
> in Fitzpatrick et al.
>
> For (2), yes, see the IEEE TMI paper I mentioned above.
>
> Simplification: I agree with the mathematical logic here. However, in
> many cases, especially those with moments about the axes that vary
> greatly, this will result in a gross overestimation of TRE at many
> places. I'm not really familiar with IGSTK, but I don't intuitively
> see why maintaining ten floating point numbers and hence giving
> accurate TRE estimated everywhere should be an enormous overhead.
>
> James' Suggestion: I agree that the name should be something like
> "PredictTargetRegistrationError", or "ExpectedTargetRegistrationError".
>
> Stephen's Suggestion: Yes, the TRE work assumes a rigid registration
> transform. It also assumes that the registration method used is
> minimization of rms FRE between corresponding fiducial points. If
> either of these assumptions is violated, the TRE formula no longer
> holds. For deformable registration methods, it's not enough to simply
> approximate TRE by looking at the registration transform as a locally
> rigid transform and derive TRE point-by-point in this way. The trouble
> is that the transform is derived in a different way, and so the TRE
> approximation is not valid.
>
> Jay
>
> -----Original Message-----
> *From:* Kevin Cleary
> *Sent:* Friday, January 06, 2006 6:48 PM
> *To:* Jay West
> *Subject:* RE: error prediction in rigid body point based registration
>
> Jay –
>
> No particular deadline, but certainly by the SPIE conference would
> be useful as several of the developers will be there
>
> I do not know this person, but I do know the person who heads the
> biophysics group and would be happy to check with him if you like
>
> Kevin
>
> ------------------------------------------------------------------------
>
> *From:* Jay West [mailto:jwest at accuray.com]
> *Sent:* Thursday, January 05, 2006 11:46 AM
> *To:* Kevin Cleary
> *Subject:* Re: error prediction in rigid body point based registration
>
> Kevin,
>
> Sorry for the delay - it's still on my list of things to do. Is
> there a deadline for this that I need to work to?
>
> BTW, I'm about to interview a guy called Zegang Dong for a medical
> physicist position here. His PhD is
>
> from Georgetown Biophysics dept. - do you know him, and if so,
> would you recommend him?
>
> Thanks
>
>
> Jay
>
> -----Original Message-----
> *From:* Kevin Cleary
> *Sent:* Thursday, January 05, 2006 8:41 AM
> *To:* Jay West
> *Subject:* RE: error prediction in rigid body point based
> registration
>
> Jay
>
> Happy New Year! Any chance you can take a look at this Wiki
> page and give us some feedback?
>
> We have been getting things organized for SPIE and I think it
> will be a good meeting
>
> Kevin
>
> ------------------------------------------------------------------
> Kevin Cleary, Ph.D. Work phone: 202-687-8253
> Associate Professor Work fax: 202-784-3479
> Deputy Director
>
> Imaging Science and Information Systems (ISIS) Center
> Department of Radiology Pager: 202-901-2033
> Georgetown University Medical Center Cell phone: 202-294-3409
> 2115 Wisconsin Avenue, Suite 603 Home phone: 301-299-0788
> Washington, DC, 20007 Home fax: 301-299-0789
>
> ISIS center: www.isis.georgetown.edu
> <http://www.isis.georgetown.edu/>
> Research group: www.caimr.georgetown.edu
> <http://www.caimr.georgetown.edu/>
> WashCAS: www.washcas.org <http://www.washcas.org/>
> Email: cleary at georgetown.edu <mailto:cleary at georgetown.edu>
> -------------------------------------------------------------------
>
> ------------------------------------------------------------------------
>
> *From:* Jay West [mailto:jwest at accuray.com]
> *Sent:* Sunday, December 11, 2005 7:49 PM
> *To:* Kevin Cleary
> *Subject:* Re: error prediction in rigid body point based
> registration
>
> Hi Kevin:
>
> Yes, I'd be happy to take a look at the page and let you know
> my take on it.
>
> Look forward to seeing you at SPIE in Feb.
>
> Regards
>
>
> Jay
>
> -----Original Message-----
> *From:* Kevin Cleary
> *Sent:* Thursday, December 08, 2005 11:26 AM
> *To:* Jay West
> *Subject:* error prediction in rigid body point based
> registration
>
> Jay:
>
> Hope all is well at Accuray. I want to ask a favor of you.
> I am the principal investigator of an NIH funded open
> source software project to develop a software toolkit for
> image-guided surgery. As one of the parts of this project,
> we are implementing a point based registration class.
> Would you be so kind to take a look at the Wiki page on
> this and give me some feedback? This is no hurry and I
> would be glad to give you some more background on the
> project any time. We are planning a small demo at SPIE.
>
> http://public.kitware.com/IGSTKWIKI/index.php/Error_Prediction_in_Rigid-Body_Point-Based_Registration
>
>
> Thanks
>
> Kevin
>
> ------------------------------------------------------------------
> Kevin Cleary, Ph.D. Work phone: 202-687-8253
> Associate Professor Work fax: 202-784-3479
> Deputy Director
>
> Imaging Science and Information Systems (ISIS) Center
> Department of Radiology Pager: 202-901-2033
> Georgetown University Medical Center Cell phone: 202-294-3409
> 2115 Wisconsin Avenue, Suite 603 Home phone: 301-299-0788
> Washington, DC, 20007 Home fax: 301-299-0789
>
> ISIS center: www.isis.georgetown.edu
> <http://www.isis.georgetown.edu/>
> Research group: www.caimr.georgetown.edu
> <http://www.caimr.georgetown.edu/>
> WashCAS: www.washcas.org <http://www.washcas.org/>
> Email: cleary at georgetown.edu <mailto:cleary at georgetown.edu>
> -------------------------------------------------------------------
>
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