Research Of Multi-parameters Rendering Method For Electrostatic Tactile System On Graphics And Images

Tactile representation technology provides natural and real interactive experience.It promotes communication between human and virtual worlds to a new stage.Electrostatic tactile representation technology can realize the sense of shape,texture and other characteristics through bare fingers touching the screen.This technology which can be applied to multimedia terminals such as mobile phones and tablets is a research hotspot in the field of tactile representation.Multimedia terminals rely on graphics and images to provide information.Tactile rendering methods can convert the visual information into force information,which are the application basis of tactile representation technology.Current electrostatic tactile rendering methods only use the amplitude parameter of driving signals.Representation abilities of amplitude,frequency and waveform parameters are not been fully studied,caused poor representational realism and limited applications of electrostatic tactile technology.In this paper,we mainly study the multi-parameters rendering method for electrostatic tactile system on graphics and images.We try to solve the rendering problem between tactile perception and three parameters including amplitude,frequency and waveform,and improve the tactile representational realism of graphics and images.The main contents of this paper are as follows:(1)Based on the electrostatic tactile representation platform of our project team,the charge transfer of the tactile representation and the standard mechanical model of the parallel capacitor are analyzed.Then a mechanical model of electrostatic tactile system is obtained,providing theoretical support for following studies.(2)The effects of grounding methods,grounding position,human impedance and insulation on system performance are analyzed.Based on these studies,the system equivalent circuit is optimized,and frequency characteristic and waveform characteristic are analyzed.Finally,characteristics of the system and the effectiveness of the proposed equivalent circuit are verified through the electrostatic measurement platform.(3)Human common perception characteristics are found and representation abilities of amplitude,frequency and waveform parameter of driving signals are studied.Then the relationship between three parameters and the common perception characteristics are established.Finally,tactile rendering models of the single parameter are obtained.(4)The factors that cause the perception difference among gaussian,sinusoidal,rectangular and triangular graphic are studied,and then a multi-parameters rendering method on graphics is proposed.The rendering models between three parameters and image features are established through common perception characteristics,and then a multi-parameters rendering method on images is proposed.Finally,graphics and images perception experiments are carried to validate the effectiveness of the proposed multi-parameter rendering method.The main innovations of this paper are as follows:(1)The necessary effect of direct grounding method and the unnecessary effect of grounding position and human impedance on electrostatic tactile system are obtained.Then,the system equivalent circuit is optimized,and the system frequency characteristic and waveform characteristic are analyzed.Finally,the optimal frequency range and the output characteristics of three waveforms are obtained.(2)Representation abilities of three parameters are obtained through experiments,and the tactile rendering models of these parameters are established through the perceived intensity and perceived roughness.Finally,the model of amplitude-perception characteristics and the model of frequency-perception characteristics are fitted.(3)Use amplitude and frequency parameters to render the image gradient,use waveform parameter to render the breakpoint feature,and then propose a multiparameters rendering method for graphics.Use perceived intensity characteristic to render the image shape feature,use perceived roughness characteristic to render the image texture feature,use waveform to render different image grayscale ranges,and then propose a multi-parameters rendering method for images.The graphics and images perception experiments are conducted to verify that the proposed multi-parameters rendering method improves the representational realism of electrostatic tactile representation system.Our research provides reference for the application of electrostatic tactile representation technology on multimedia terminals.