How to separate the foreground from the background in an image?

Hi,

I am working on a project related to image matting. I am trying to separate the foreground of an image from the background. Can anybody please help?

[Image Analyst]

Most likely, if you supply more information such as an image and a description of what is the foreground and what is the background and what you want to measure (area, count, perimeter, color, etc.)

Answer 1

[Image Analyst]

See my Image Segmentation Tutorial, BlobsDemo: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Answer 2

[Walter Roberson]

There are a number of "optical illusions" around that prove that there is no objective meaning to "foreground" and "background". What is "foreground" in one interpretation might be "background" in a different interpretation of the same image.

[Image Analyst]

I'm planning on giving a seminar on optical illusions in a couple of months. What are some good examples of that?

Also, if you have any images of "one-eyed stereo" illusions, I'd appreciate knowing where (I have only a few and don't remember where I got them).

[Walter Roberson]

I am thinking of a couple of the usual suspects, Necker Cubes, "The Young Lady and the Old Crone", the Chalice.

Looking around briefly, the hollow Chaplin mask is good

I had not seen the Necker Lattice before.

A few others at http://en.wikipedia.org/wiki/Ambiguous_image

[Image Analyst]

Thanks for those. By the way, there is some research into "Main Subject Detection" - I think by those involved in stockphotography databases (CBIR) and camera manufacturers:

http://www.bing.com/search?q=main+subject+detection&qs=n&form=QBLH&pq=main+subject+detection&sc=0-0&sp=-1&sk=&cvid=2c077cda730d4ae3a447c74ab97b7343

https://www.google.com/#q=main+subject+detection

Also, attached is an example that I've collected of one-eyed 3D. Blow it up full screen, it looks fairly planar with both eyes open, then close one eye and it looks more 3D-like than if both eyes are open.