[Insight-users] [ITK Community] Cost function value increases

[Brian Helba]

I would try some much larger maximum step values. You program appears to be
spending iterations while not making very much progress at the start.

Also, when you're tuning things, it can be helpful to print the moving
image parameters on each iteration, in addition to the cost function.
On Nov 27, 2013 5:42 PM, "Hana Cherif" <hanacherif62 at gmail.com> wrote:

>
> Hello every body !
>
>
> After execution of my images' registration program , using this components:
>
> Regular Step Gradient Descent Optimizer,
> Mean Squares Image  To Image Metric
> Bspline interpolator
>
>  I get this results::
>
>
> Iteration number:     Cost function value
>
>
> 0                        2732.74
> 1                        2700.84
> 2                        2699.27
> 3                        2701.48
> 4                        2703.19
> 5                        2700
> 6                        2704.12
> 7                        2705.1
> 8                        2705.27
> 9                        2705.4
> 10                        2702.91
> 11                        2705.15
> 12                        2713.1
> 13                        2720.48
> 14                        2720
> 15                        2715.81
> 16                        2704.64
> 17                        2687.46
> 18                        2666.14
> 19                        2639.91
> 20                        2613.11
> 21                        2587.55
> 22                        2564.89
> 23                        2546.22
>
> I use this parameters:
>  optimizer->SetMaximumStepLength(0.10 );
>  optimizer->SetMinimumStepLength( 0.05);
>  optimizer->SetRelaxationFactor(0.5);
>
> My question is : as you see i the results the value of the cost function
> increases i want to know why can be the reason of this results please!! is
> it just a probleme of parameters??
>
> Thanks !
>
>
>
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