A method and a system for automatically mapping obstacles within a bin that stores content, the system may include: a location estimator that is arranged to calculate, in response to detection signals, an estimated shape of an upper surface of the content; wherein the detection signals are generated by a receiver in response to radiation signals reflected or scattered from multiple points within the bin; and an obstacle detector that is arranged to detect at least one obstacle point that belongs to an obstacle in response to (a) the estimated shape of the upper surface of the content, and (b) an expected shape attribute of the upper surface of the content.