how to extract mahatama gandhi watermark from currency?

i am doing project on fake currency recognistion. i do not know which method should be useful to extract watermark from image as i am new to matlab.

[Rik]

Have a read here and here. It will greatly improve your chances of getting an answer.

Provide some examples of what you have tried already. Also, a well-designed recognition method could also be used for counterfeiting, which I would like not to help with. So can you also provide some context for this question?