[Insight-users] Transform the contour from image to chaincode

[Luis Ibanez]

Hi Jiang,

Please do the following:


1) Identify the pixel were your algorithm is
    stopping prematurely


2) Go to the same index in the original image,
    where you have the contour in 0 and 100 values.
    (e.g. the image as it is before you set any
     of the contour points to zero).

3) Take a 7x7 neighbor centered on this pixel
    and post all the values of this neighbor
    (arranged in a matrix) to the users-list.



Thanks


   Luis



---------------------
Jiang wrote:

> Hi, all,
> 
> By some filters of itk, I get one closed contour as one image. This 
> image is one binary image that
> 
> the pixel value is 100 when is pixel is in the contour, otherwise it is 0.
> 
> Now I want to convert this contour to ChainCode. My pseudocode is as follow:
> 
>  
> 
>   Search the image from the first pixel to find the first point in the 
> contour;
> 
>   Add this point to ChainCode list, and set its value to 0;
> 
>   Search the immediate neighbors of of this point to check if it is on 
> contour;
> 
>          If this point’s value==100;
> 
>          {        Add it to ChainCode, and set its value to 0;
> 
>                    Loop searching
> 
>          }
> 
>          else
> 
>                    Stop searching;
> 
>                    Finish the ChainCode;
> 
>  
> 
> // The order of checking neighbors. Assume the current points is at “0”.
> 
> //    ------------------------    
> 
> //   |  5  |  3  |  8  |
> 
> //   |-------------------------|
> 
> //   |  1  |  0  |  2  |
> 
> //   |-------------------------|
> 
> //   |  7  |  4  |  6  |
> 
> //    -----------------------
> 
>  
> 
> This searching method works, but not always. Sometime, it stops at 
> somewhere, but the contour is
> 
> not completed. And the stopped point is not different as other found 
> points. I even enlarge the
> 
> neighbourhood to a bigger circle. But it is still not stable.
> 
>  
> 
> Maybe my question is beyond the range of this itk maillist. I’m really 
> upset with this problem.
> 
> Who can give me some suggestions?
> 
>  
> 
> Thanks a lot!
> 
>  
> 
>  
> 
> Jiang
> 
>  
> 
>  
> 
> 
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> 
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