How can I get the outer most contour of the syntax (contour)?

Using the syntax (contour), I will have 10 contours for a binary image!! and when I assign 1 in the syntax, I will get the inner most contour. How can I get the outer most contour only?

[Jan]

What does "when I assign 1 in the syntax" mean? Please post the code.

If you have 10 contour lines and "1" is the innermost, maybe "10" is the outermost... But this is a guess only.

[Shahin Safazadeh]

>> contour (mask) % the result of this line is 10 concentric contours with 10 different diameters and colors.

>> contour (mask,5) % the result of this line is 5 concentric contours with 5 different diameters and colors.

>> contour (mask,1) % the result of this line is just 1 contour, which is the inner most contour among the whole contours.

[Image Analyst]

Please attach your binary image and tell us what you want. I think you can get what you want without using contour, such as by hole filling with imfill(), or by using bwperim(), bwconvhull(), or bwboundaries() or something. It really doesn't make much sense to use contour on a binary image if you think about it.

[Shahin Safazadeh]

Basically, my mask is in gray scale (256). However, I converted it to binary in order to get the contour. However, I think bwperim() might works here. (I didn't know this syntax) Anyway, I attached the mask file. Please let me know how to get the largest contour instead of the perimeter pixels (if it is possible)

Thank you very much