How to convert specific part of the image into binary form.

http://www.freeimagehosting.net/dsr48

How do i want to convert only the green part to binary image so it will become like tis http://www.freeimagehosting.net/kbkac

Answer 1

[Image Analyst]

How about

binaryImage = grayImage > 50; % Or some other value.

[Wei Qing]

did the code convert the image to binary image? no need to use im2bw() function? what is the number mean?

[Image Analyst]

Yes, that is a binary image. It has type logical. The number says that you want every pixel with pixel value greater than 50 to be 1 (true) or "foreground", and that everything else (darker than 51) will be 0 (false) or "background."

[Wei Qing]

i found another way to solve the problem. Thanks for helping anyway.

[Image Analyst]

You're welcome. What way did you use? I never use im2bw() because it takes thresholds in the range of 0-1 and I find that very inconvenient. I'd rather pass in a gray level but it's not smart enough for that (yet - I'm going to bring it up with them). Internally im2bw ()does what I did. It just has to convert either the threshold to an actual gray level or convert the image to the range 0-1. But then it has to do the thresholding like I did it.

[Wei Qing]

actually i am using the wide line detector code to get the above image. http://www.mathworks.nl/matlabcentral/fileexchange/35754-wide-line-detector So i modified the codes in huang_usage.m in order to get what i want.