How to find image's background area

Hello!

I am new to image processing in Matlab. I need to find the size of the covered area (or the size of empty space) in the following image.

Is it possible?

Thanks in advance.

Answer 1

[Image Analyst]

The image doesn't seem to exist. Please re-upload it.

In the meantime, see my Image Segmentation Tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

[Andre Luis]

Sorry, trying to re-upload.

Actually, I think I got what I wanted using im2bw and bwarea commands.

[Image Analyst]

What are you defining as "covered" or "empty"? Can you go simply by how dark it is? Like

emptySpace = grayImage < someThresholdValue;
pixelArea = sum(emptySpace); % Area in pixels.