Comments on: Active Contour Matlab Code Demo

By: Yossi

Yossi — Tue, 01 Sep 2009 07:08:49 +0000

Dear Mewada,
Could you please share your modified program (with the histogram energy)?
I guess it will save me a lot of time.
Thanking you in advance,
Regards
@Mewada Hiren K

By: Shawn Lankton

Shawn Lankton — Mon, 17 Aug 2009 13:37:10 +0000

In my implementations, I typically use $\epsilon=0$. In that case, the Heaviside function is simply 1-sign($\phi$). That cuts down on quite a few computations.

By: Mewada Hiren K

Mewada Hiren K — Mon, 17 Aug 2009 13:34:49 +0000

Earlier i asked about the histogram separation energy in your program of Local region based image segmentation , but if i want to change the Heaviside function , then how can i do in your program , because i don’t find the function for heaviside that is mentioned as in your paper.

By: Shawn Lankton

Shawn Lankton — Wed, 22 Jul 2009 17:58:30 +0000

@Mewada Hiren K Great, good work. The execution time is a drawback of the histogram separation energy. I plan to release new codes soon which will be much faster than the implementation you are using. The paper discusses some of the limitations of the algorithm. From experimenting it seems that it works best in medical applications where the contour can be initialized close to the object. For processing natural images, automatic selection of the localization radius is a challenge that is still an open question.

By: Mewada Hiren K

Mewada Hiren K — Wed, 22 Jul 2009 17:55:44 +0000

Dear Sir,
i have successfully modified your program for histogram separation based image segmentation. But it takes much time execution. Another thing i want to ask is what are the limitation of your algorithm , so that it is not segmentating object succesfully for other images. I tried much , but i could not get the answer. One request is i am also doing work in the same field. what next i can do, will please guide me.

Thanking You

By: Shawn Lankton

Shawn Lankton — Sat, 11 Jul 2009 15:16:29 +0000

@Mewada Hiren K You should first implement the global Bhattacharyya (Histogram Separation) energy. This is described well in the paper by Michailovich et. al. Localization is a snap once you have the global version working : )

By: Mewada Hiren K

Mewada Hiren K — Sat, 11 Jul 2009 08:20:56 +0000

Sir, i tried to designe code based on histogram separation energy and that part added as third method in your given code i.e. 1st is CV model, 2nd is Yezzi model and 3rd is i my design code, as below:
Jin=I(upts); Hin=hist(Jin);Pin=Hin/length(Jin);, Similarly for exterior part i calculate the probabilty of pixel with in radius of defined circle.
Function is : Bhattachrya Coefficient B= sum(sqrt(Pin(:),Pout(:)));
t11= B*(1/Ain’-1/Aout’)); t21= K*(255-I(idx)); t22= (sqrt(Pout/Pin))/Ain’-(sqrt(Pin/Pout))/Aout’
F=-(u-v)*(t11+t21*t22);
but i am not gettting the result.. So it what wrong i am doing?
Thank You Sir,,

By: Shawn Lankton

Shawn Lankton — Mon, 06 Jul 2009 13:53:24 +0000

You can use any smoothing kernel you like. In my case, I used a Gaussian smoothing kernel with a standard deviation of 5.

By: Mewada Hiren K

Mewada Hiren K — Mon, 06 Jul 2009 09:24:29 +0000

In your paper “localizing region based active Contours, you did not define the kernal which is utilized for histogram separation energy measurement. So can you guide me some detaio in that algorithm….
Thanking You,

By: raman

raman — Tue, 05 May 2009 12:39:13 +0000

I want to use the Active Contour Toolbox, but I’m currently having Matlab 7.1 sp1. The Active contour toolbox says it works with newer versions only. Which version should I buy??