Research On Trigger Motion Combination Form And Interface Optimization Design Of An Eye-control Interaction System

With the prevalence and development of "human-centered" design concept,technology of human-computer interaction(HCI)has been rapidly developed with the support of hardware and software equipment such as Internet technology and sensor technology.More and more high-tech human-computer interaction equipment and methods have been applied to medical care,education,military,virtual/augmented reality and other fields,and multi-channel and multi-mode human-computer interaction technology has become a popular research field.Among them,the interaction form of taking human eye movement data as the computer input trigger signal,namely eye-controlled human-computer interaction,has attracted people's attention because of its natural,direct and fast operation characteristics,and is a forwardlooking HCI research direction.At present,gaze is the most common trigger action in the eyecomputer interaction system,which could cause serious Midas contact problem,thus affecting the stability and usability of the eye-controlled HCI system.This paper summarized the benefits and limitations of various eye-controlled HCI system,innovatively putting forward using eye blink as the trigger of interactive elements on the interface.Through the combination of a single blink and other eye movement actions,the compound interactive action was further proposed based on an eye blink,avoiding the interference of involuntary blinks on the system.Tobii eye tracker,HD camera hardware and Unity software were used to build the eye-tracking interaction platform,and the specific form of eye-tracking trigger actions and the design parameters of corresponding interface elements based on blinking were deeply explored.In the research of compound triggering action of blinking,two kinds of compound triggering methods were put forward.One is the motion made up of several continuous blink.The other is the combination of gaze motion and one-time blink.Twenty graduate students with good vision from Southeast University were invited as experimental subjects.Through random target triggering experiments,the following conclusions are drawn:(1)when the trigger action is the combination of continuous blinks for several times,the amount of eye blinks has a great influence on success rate and reaction time of people's operation.The more blink actions in the trigger combination action,the longer reaction time of people's operation,the lower success rate of people's interaction.Besides,the time interval between two blink motions in one trigger action increases gradually with more blink motions,indicating that more blink times could bring more eye fatigue.Therefore,two blinks in one trigger action could have a higher trigger success rate and a lower task load.(2)when the trigger action is the combination of one gaze and one blink,the duration of gaze time has a significant effect on the success rate and reaction time of people's operation.The longer the gaze time in the trigger action,the longer the user's reaction time for the operation.Besides,the success rate of triggering the interface elements reaches the highest when the gaze time is 400 ms.So,"400ms gaze +1 blink" is recommended as the optimal choice in this type of trigger action.Both of these two trigger actions have a success rate of more than 95%.In the research of the design parameters of interactive elements in the “blink-based” user interface,evaluation and ergonomic experiment of the size and spacing of interactive elements were carried out based on target search task.The following conclusions are obtained :(1)Element size has a significant effect on the accuracy rate and reaction time.When the control size is less than 250 px,the larger the element size is,the shorter the reaction time of the user will be,and the effect will not be significant after the size is greater than 250 px.When the element size is less than 200 px,the larger the control size,the higher the success rate of interaction,and the effect is no longer significant after the size is greater than 200 px.Therefore,when the screen resolution is 1920*1080px and the distance between the user and the display is 60 cm,200px becomes the recommended value for the design of interactive elements in the blink-based HCI.(2)The spacing between elements has a partial effect on the accuracy rate of people's interaction.The overall trend is that the larger the spacing,the higher the triggering accuracy.This effect is most obvious when the spacing between "0.4 times the element size" and "0.6 times the element size".At the same time,the spacing has a partial significant effect on the reaction time,and the general trend is that the larger the element spacing is,the longer the reaction time will be,and the effect is most obvious when the spacing is between "0.6 times the element size" and "0.8 times the element size".Therefore,when the final spacing is selected as "0.6 times the diameter of the element",the whole system has a better performance.Finally,based on the conclusions above,a multimedia player was designed as a verification interface,and users were invited to have a practical experience based on a specific task stream,and the NASA-TLX scale was filled in.The verification evaluation results showed that the verification interface has a low task load,which turned out the previous conclusions are meaningful.The content discussed in this paper overcomes the Midas contact problem in the traditional eye-machine interaction process and has a wide range of application value.