<div><div>Hi Amy,</div><div><br></div><div>A couple things for consideration:</div><div><br></div><div>1) Instead of modifying the itkBSpline…Filter that is currently in the review directory, you could just download the itkBSplineControlPointImageFilter class from the N4ITK contribution which takes as input, a set of control points and evaluates the B-spline object values, derivatives, etc. I wrote it as a companion class to the original scattered data approximation filter. </div>
<div><br></div><div>2) These classes assume uniform knot spacing where the parametric domain is defined by the user-specified image domain. Thus the user does not specify the knot vectors as they are already implied by the assumptions of the algorithm. </div>
<div><br></div><div>Let me know if you have any other questions/concerns,</div><div>Nick </div><div><br></div><div class="gmail_quote">On Mon, Jan 4, 2010 at 2:37 AM, Amy C <span dir="ltr"><<a href="mailto:mathematical.coffee@gmail.com">mathematical.coffee@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hi Luis,<br>
<br>
Thanks a lot for that, I had a look at the class and it does seem do
what I'd like it to (and then some), so I might modify it to just do
the evaluating & calculating of derivatives (I need the bspline
object, but don't need it to approximate any data). After perusal of
the code, I think my problem is to do with my understanding of
B-splines. I thought I understood them, but I've become more and more
confused as to exactly how many knots/control points are needed and
where they should be placed. I'm going to do a bit more reading and
then come back this question later.<br>
<br>
thanks for all the help,<br><font color="#888888">
Amy</font><div><div></div><div class="h5"><br>
<br><div class="gmail_quote">On Mon, Jan 4, 2010 at 6:26 AM, Luis Ibanez <span dir="ltr"><<a href="mailto:luis.ibanez@kitware.com" target="_blank">luis.ibanez@kitware.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
<div>Hi Amy,<br>
<br>
There are several forms of BSplines in ITK.<br>
<br>