We can utilize the observer framework for recognizing error states and sequences. The idea behind this recognition task is to be able to report on visually incorrect sequences. In particular, if there is a pre-determined observer model of a particular inspection task under observation, then it would be useful to determine if something goes wrong with the exploration actions. The goal of this reporting procedure is to alert the an operator or autonomously supply feedback to the inspecting robot so that it could correct its actions. An example of errors in inspection is unexpected occlusions between the observer camera and the inspection environment, or probing the part in a manner that might break the probe. The correct sequences of automata state transitions can be formulated as the set of strings that are acceptable by the observer automaton. This set of strings represents precisely the language describing all possible visual task evolution steps.
