how to subtract background image

i need only that person

Answer 1

[Walter Roberson]

imsubtract()

Note that background subtraction does not itself locate any object or trim away background: after you have done the subtraction you need to do that. In your case, you essentially have no background and should proceed directly to locating the object.

Answer 2

[Image Analyst]

See my Image Segmentation Tutorial for guidance on how to threshold a bright object on a dark background and then crop out that bright blob.

http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862