A system includes an imager, such as a 3-D structured light imaging system, and gesture logic in data communication with the imager. The imager is configured to create an image of the motion of a mobile subject. The gesture logic is configured to: generate a first mapping of the current motion of the mobile subject based on the image, access a stored second mapping of a model gesture, and compare the first mapping to the second mapping to determine a operational condition of the mobile subject.