Removing Background (To count cells in image)

I want to count cells in a image.
Assistant refered to hints(graythresh, im2bw, bwdist, watershed)
But I think, first, I need to elliminate background pixels... How can I do?

Answer 1

[Grzegorz Knor]

You do not have to do, just follow the assistant instructions :)

Here's the example:

http://blogs.mathworks.com/steve/2006/06/02/cell-segmentation/

Answer 2

[Image Analyst]

Thresholding (im2bw) does remove background, in a sense. It gives you a binary image where the foreground is 1 and the background is 0.

See my BlobsDemo for a complete tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862