Removing grey pixels from an image

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Tarik Razak
Tarik Razak on 7 Feb 2012
Edited: Walter Roberson on 3 Oct 2013
Hi I have an image in which there are black pixels and gray ones. I am trying a way to remove the gray pixels and just keep the black ones. I dont want to do im2bw because I believe it will just turn the gray to black. Thanks for the help
  2 Comments
Tarik Razak
Tarik Razak on 7 Feb 2012
with white or nothing thanks

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Answers (2)

Image Analyst
Image Analyst on 7 Feb 2012
You can't replace with nothing because the image must remain rectangular. So try this
imageArray(imageArray ~= 0) = 255;
That will turn all pixels not equal to zero (pure black) to 255 (pure white). If you need 1 instead of 255 (like it's a logical or floating point image) then just use 1 instead of 255.
imageArray(imageArray ~= 0) = 1;

Shiva Arun Kumar
Shiva Arun Kumar on 7 Feb 2012
Why would this not work?
bw=im2bw(I,0)
Where I is the image that was read in.

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