Comments on: GrowCut Segmentation In Matlab

By: Shawn Lankton

Shawn Lankton — Sun, 31 Jan 2010 16:33:48 +0000

@Ray Right-on. Thanks for answering some of these other questions, too!

By: Ray Phan

Ray Phan — Fri, 29 Jan 2010 18:47:55 +0000

Hi Shawn,

Never mind about that previous post… I just didn’t bother to crunch in the number myself. Your 441 figure is in fact sqrt(3*255^2)… thanks!

@Jhon, the 441.673 figure is the greatest possible L2 norm between the darkest and brightest colours… in this case, it’s black and white, so sqrt((255-0)^2 + (255-0^2 + (255-0)^2) = sqrt(3*(255^2)) = 441.673.

Hope this helps,
- Ray.

By: Ray Phan

Ray Phan — Fri, 29 Jan 2010 18:45:29 +0000

Hi Shawn,

Just a quick comment regarding maxC… if it is indeed the maximum value of the cost function, if you’re using the L2-norm in RGB space, shouldn’t the max be sqrt(3*(255^2))? I’m not sure where you got the 441 figure from… as 256^2 is 65536, unless you considered a perceptually uniform colour space, but judging from your code, it is RGB data.

In any case, that was just my two cents. Your code is actually quite good, and I actually stumbled upon this posting by accident. I was looking for something else all together, and found this GrowCut entry you made. I’m considering using it for another application I’m developing.

Thanks,
- Ray.

By: Anonymous

Anonymous — Wed, 20 Jan 2010 07:58:00 +0000

I will learn it .

By: Shawn Lankton

Shawn Lankton — Fri, 18 Dec 2009 13:41:59 +0000

@Jhon maxC is (256)^2 which is the maximum value of the cost function. To get the coordinate of the seeds, you simply search the “seed image.”

By: Jhon

Jhon — Wed, 16 Dec 2009 20:38:37 +0000

Dear sir,
From where do you get maxC? How do you know the coordinate of the seeds?

By: Shawn Lankton

Shawn Lankton — Mon, 09 Nov 2009 07:02:42 +0000

@tariq With grow-cut you must be careful with your initializations. If at first your segmentation is incorrect, try adding some additional initialization points both inside and outside your object. As shown in the post, the ‘inside’ initialization points should have a value of 1 and the ‘outside’ initialization points should have a value of 0.

By: tariq

tariq — Thu, 05 Nov 2009 07:07:10 +0000

sir,
i have a question about growcut segmentation that you use lotus image for segmntation,find result
but we use that algotrithm in another image m,we will not get proper result,
sir any program setting for that we run on different image
plz send reply as early as possibl