A method for locating objects enclosed in a medium, comprising the steps of generating a measurement signal correlated with an enclosed object; using the generated measurement signal to produce a signal which represents a difference between at least a first state which is “object detected” and at least a second state which is “no object detected”; switching from the first state “object detected” to the second state “no object detected” if a magnitude of the measurement signal being measured currently falls below a previously measured local maximum value of the measurement signal by a predefined first percentage.