An investigation of a simplified method to determine a pilot's instrument scan pattern

An architecture for a low-cost instrument scan recording system was designed. This system used a sequence of video images of the pilot's face and required the pilot subject to wear a small, black three-panel visor with which to highlight changes in the position and orientation of the pilot's head. An image of a simulated visor, at varying positions and orientations, was then compared to the actual gray-scale video image. A image-matching figure of merit and search routine was implemented to find the best image match. A similar search for the orientation of the pilot's irises was then performed and the point of regard calculated. Perspective calculations and four coordinate transformations were required for this model. Once such a system (comprised of only a video camera and a computer code to process the image data) is fully developed several benefits over current systems would be realized including less intrusiveness, lower cost, simplicity, and reasonably free head movement in translation and rotation.; A model of the accuracy of the above system was developed and validated. The accuracy of this type of instrument scan recording system is dependent on multiple factors such as the pixel resolution used for video capture, the pilot-to-camera distance, and so forth, The model was validated by comparing the theoretical accuracy (for a given pixel resolution) to the experimentally-observed accuracy during measurement of a typical instrument scan sequence. Experimental results presented show that for a 640 x 480-pixel video-capture resolution a visual angle accuracy of approximately four and one-half degrees was both expected and observed. By extension of this methodology, the pixel resolution required for any other particular visual angle requirement could be obtained.; Further effort will be required before in-situ use in the cockpit environment to account for lighting variations and occlusion of the iris by the eyelid. With the frequent advances in the computer processors, memory, and video-capture capability this type of system has definite potential as an non-invasive estimation tool accurate enough to provide in-flight instrument scan analyses at a fraction of the cost of comparable systems.