Gibson's Optical Flow and the

When watching the GoPro clips, refer to the following and bear in sight Gibson’s optical flow. Reference the iPad navigation and the real environment.

A way to see surfaces that were continuous in the background, layered, and giving some form, Gibson termed this ‘layout’ (1986, pp. 157-159). A layout has a place and objects, with features from which the observer perceives, and in this way, the perception of layout in a three-dimensional space is not seen in the same way as the perception of depth. This is when Gibson’s work gets interesting.

According to Gibson’s ground theory, this layout involves self-perception and is continually changing as the observer moves (Gibson, 1986, p. 148), and from this angle, a view from the top or the side is what gives some distance from the object, a perspective to see distance on where the body is positioned, not necessarily depth perception. In this visual world of Gibson, the optical flow is generated by motion perspective, and it is the observer who ‘picks up’ the information that is perceived in the surroundings, including the medium of the air and the surfaces and their layout. For a helicopter approach to landing as well as take off to climb, the optical flow flows from the centre of the helicopter, radiating outwards.

The perception of distance has significance. On approach and climb, the optical flow has relevance because the flow-field from the eyes is at height-level, whereas when landing and taking off, there is a view to see the ground by the feet which begins to lift or weight. Depending on the helicopter type, the helicopter’s view below by the feet allows for some visual cues.

The optical flow outwards from the approach is at eye level, which then changes to direct side view and below view. An example of an eye-height level view from the cockpit would be at 800ft at 50kts, descending, setting up the approach. In a field of view that comprises an eye-level view, a perspective would show flow vectors flowing around the sides of the aircraft near the surface, a typical part of the helmet-mounted display formats (Padfield, 1996, p. 525). The optical flow at a particular height during descent would elicit a specific reaction to the visual cue indicating where to land. The GoPro helmeted by the pilots gives an idea of the optical flow-field on descent, approach, then landing, and take off.