Research On The Information Encoding Method Of Helmet Mounted Display System Interface Based On Visual Perception Theory

With the rapid development of aerospace and computer technologies, the visual avionics interfaces of fighters have transformed from traditional mode to digital mode over the past few years. In particular, there will be higher requirements for human-computer interactions of fighter systems in the future with the application of the Helmet Mounted Display System (HMDs) Because of the extremely high design requirements for display of interface information/codes and human-computer interactions in terms of helmet tracking/display, dynamic information presentation and target symbol marking and so on, interface of HMDs will be different from conventional avionics interface. In developed countries like America, certain research has been conducted in pertinent fields. However, China still falls behind America in research on cognition of avionics interface and information coding design for interface of HMDs. In addition, information coding for interface of HMDs based on visual cognition is still an unknown field to be explored and filled up across the fields of design, engineering and psychology. In consideration the importance and insufficiency of this problem, interface of HMDs is examined in this paper based on pilots’visual perception theory to carry out following research work in light of icon, information and color coding.(1) Fundamental principles of interface visibility for HMDs are put forward. Design parameters of display system are summarized for information coding on the interface of HMDs, particularly including display methods, exit pupil, eye distance and field of view. From the perspective of pilot visual and perceptual cognition, fundamental principles of making information on the interface of HMDs visible are proposed in terms of icons, brightness, contrast, resolution, characters and colors.(2) A method is developed for reflecting connections between pilots’visual cognition and interface elements of HMDs. According to methods of visual analysis such as Shannon’s models for information communication systems, Wickens’ visual search models and Endsley’s SA theoretical models, importance is attached to analyze cognitive problems such as situational perception, selective attention and cognitive load involved during information transmission from the perspective of information coding on the interface and brain information decoding, to sum up hierarchical relationships between information coding for design elements and cognitive mechanism.(3) In light of icon characteristics on the interface of HMDs, information layout and interface colors, pertinent information coding methods and design principles are brought forth. Pilots’ information needs in different flight tasks are completely, systematically and hierarchically divided. According to mapping and relevance theories from visual cognition to design elements, icon characteristics on the interface, layout of alarm information and color application are experimentally studied by experiment paradigms such as single change detection and cause detection. Pursuant to experimental results, coding methods and design principles concerning icon characteristics on the interface of HMDs, information layout and color application are obtained, summarized and put forward.(4) Based on the interface coding methods for HMDs reflected from visual cognition and characteristics of interface information, brand new codes are designed for information elements of the interface like indicated height, speed, direction and pose. Priorities are given to optimize icon marking on the interface of HMDs, layout of information architecture, processing of background colors and alarming methods. Experiments are carried out to evaluate cognitive load according to design proposals. Besides, experimental results are tracked by eye movements, verifying that the coding methods and design principles put forward in this paper are effective and feasible.In this paper, information coding and test methods are provided for designing the interface of HMDs, thus bringing forth effective research ideas for exploring problems about human-computer interaction of HMDs. Therefore, positive contribution is made to improving avionics interface design of Chinese fighters, strengthening cognitive abilities of pilots and making more correct decisions or judgments from the perspective of design.