how to automatically cropp the picture

this is the image before cropping.

/matlabcentral/answers/uploaded_files/24364/crp1.png

i need a program which will automatically crop like the one below

/matlabcentral/answers/uploaded_files/24365/crp2.png

i can get rid of extra outer space and thus reduce image sixe. i thought of finding the left most and right most, bottom most and top most pixel points and keeping this points we can crop upto those points. please help me with the code..