Electro-optical MASINT is a subdiscipline of Measurement and Signature Intelligence, (MASINT) and refers to intelligence gathering activities which bring together disparate elements that do not fit within the definitions of Signals Intelligence (SIGINT), Imagery Intelligence (IMINT), or Human Intelligence (HUMINT). In other words, MASINT may give warning before characteristics visible to IMINT are clear, or it may help validate or understand the pictures taken by IMINT.