Thanks for your reply.<div>I compiled itk in Debug Mode ! That may very much make a difference. Thank you for noticing that. I will set the radius to a smaller value later on and see what happens. Currently I leave radius as default in both itk and matlab. <br>
<br><div class="gmail_quote">On 7 March 2010 08:39, Luis Ibanez <span dir="ltr"><<a href="mailto:luis.ibanez@kitware.com">luis.ibanez@kitware.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi Zhenchao,<br>
<br>
<br>
1) The itkAdaptiveHistogramEqualizationImageFilter took<br>
<br>
9 minutes 25 seconds<br>
<br>
to run in an input image of size: 3072x2304<br>
<br>
in a laptop LATITUDE E6500, with processor:<br>
Intel(R) Core(TM)2 Duo CPU T9600 @ 2.80GHz<br>
Running Ubuntu 9.10,<br>
with code compiled with gcc 4.4 in Release mode.<br>
<br>
<br>
with the following parameters:<br>
<br>
Radius = 10<br>
Alpha = 1.0<br>
Beta = 0.25<br>
<br>
<br>
The radius parameter is obviously critical here.<br>
<br>
You should anticipate that the computation time<br>
is proportional to the square of the radius<br>
(for 2D images)<br>
<br>
A radius of 10 is using a region of 21x21 pixels<br>
for performing the local computations.<br>
<br>
<br>
2) As a reference: Using a radius value of 2,<br>
leads the filter to run in 25 seconds, on the<br>
same input image.<br>
<br>
<br>
What value of radius are you using with the ITK filter ?<br>
<br>
What value of radius are you using with Matlab ?<br>
<br>
and<br>
<br>
Very important:<br>
have you compiled your code for "Release" mode ?<br>
<br>
<br>
<br>
Regards,<br>
<br>
<br>
Luis<br>
<br>
<br>
------------------------------------------------<br>
<div><div></div><div class="h5">On Fri, Mar 5, 2010 at 4:32 AM, Zhenchao Li <<a href="mailto:cockneykevin@gmail.com">cockneykevin@gmail.com</a>> wrote:<br>
> Hi,<br>
> I'm using itk's builtin adaptive histogram equalization to equalize an<br>
> image(3000*3000 in size), with the default arguments the process seems to<br>
> run forever. However if I use matlab's adaptivehisteq function the result<br>
> returns immediately. After googling I find that matlab uses an algorithm<br>
> called contrast limited AHE, while itk uses the original AHE. The difference<br>
> is that the former process the image block by block while the latter<br>
> processes the image globally.(not sure how really it works). So, am I stuck?<br>
> Or is there a way to use CLAHE in itk? The current AHE in itk is really<br>
> slow, any suggestions?<br>
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