| In recent years,tactile representation can provide rich tactile feelings and achieve real immersion,which is a research hotspot in the field of human-computer interaction at home and abroad.At present,the main tactile representation technologies including electrostatic force,squeeze film effect and mechanical vibration are applied to mobile terminals.However,the tactile representation technology based on a single force feedback mechanism cannot meet the need for the tactile representation reality because of the range and dimensional limitation of the feedback force and the lack of tactile feelings.International has further studied the tactile representation device and rendering methods based on multiple force feedback mechanisms.Meanwhile they prove that the tactile rendering method of combining multiple force feedback mechanisms can effectively improve the effect of tactile representation in terms of graphics and images.Based on this,this paper continues to study the combining mechanism of tactile representation,the characteristics of tactile representation devices and the rendering method of tactile representation,which are based on electrostatic force,squeeze film effect and mechanical vibration.Based on above,this paper further researches a new rendering method of improving the tactile representation reality,focusing on rendering problem of 3D bump(three-dimensional shapes such as bump,hole,geometric figures,etc.),image contour and image texture.The main contributions and innovations of this paper are as follows:(1)According to the tactile representation principle of electrostatic force,squeeze film effect and mechanical vibration,the feasibility of the combining three technologies is demonstrated from the combining device and the rendering algorithm.According to the people's needs for functional requirements of the tactile representation device combining electrostatic force,squeeze film effect and mechanical vibration(three-model combining tactile representation device),this paper completes the development of three-model combining tactile representation device,designs the communication between the lower computer and the upper computer,writes the control interface of the upper computer and the corresponding communication program,and realizes the hardware driving of three-model combining tactile representation device.This paper further tests the performance of three-model combining tactile representation device,such as the error range of the amplitude and frequency of the driving signal,the delay of the tactile representation system and the influence of driving signal amplitude and frequency of mechanical vibration on the absolute threshold and difference threshold of electrostatic force and squeeze film effect,which provide a theoretical basis for the subsequent combining tactile rendering method.(2)A 3D feature tactile representation rendering method with combining electrostatic force,squeeze film effect and mechanical vibration is proposed,and it is realized on the touch screen.The subjective evaluation experiment result of twelve participants shows that the maximum height is 4.2mm and the most adaptation range of spatial wavelength is 40-50 mm for the proposed method.This method includes perception model establishment,3D feature extraction and mapping of driving signal parameters.First,the driving signal amplitude of electrostatic force,squeeze film effect and mechanical vibration is mapped to the tactile perception intensity,and the driving signal frequency of electrostatic force is mapped to the roughness intensity.Then,because the change of gradient information is the same as the variation trend of the lateral force,the mapping model between the perception intensity of electrostatic force and squeeze film effect and the gradient information is established.Because the change of depth information is the same as the variation trend of 3D real height,the mapping model between the perception intensity of mechanical vibration and the depth information is established.The objective evaluation experiment result of twelve participants shows that the proposed rendering method effectively improves the tactile representation realism.This paper further researches the 3D maximum height that can be rendered by the proposed rendering method and the influence of 3D spatial wavelength on the proposed rendering method.(3)An image tactile rendering method with combining electrostatic force,squeeze film effect and mechanical vibration is proposed,and it is realized on the touch screen.The subjective evaluation experiment result of twelve participants shows that the proposed rendering method(7.65 points)can improve the tactile representation effect of the contour and texture of image compared with combining electrostatic force and mechanical vibration(5.43 points)and combining electrostatic force and squeeze film effect(5.18 points).The specific progress of this rendering method is as follows: The Canny algorithm is used to extract the contour information and texture information of the image.Then,because the contour information represents the general trend and edge change of the image,the mapping model between the driving signal amplitude of electrostatic force and squeeze film effect and the gradient information of the contour is established.Because the texture information is used to represent the roughness of the image surface,the mapping model between the driving signal amplitude of mechanical vibration and the driving signal frequency of electrostatic force and the height information of image texture is established respectively.Finally,the twelve participants perform a subjective scoring experiment on six different images under different rendering methods.This paper studies the tactile representation technology of combining electrostatic force,squeeze film effect and mechanical vibration from the aspects of basic theory,hardware device,combining mechanism characteristics,rendering algorithm,etc.,and provides a reference for the realization of tactile representation of mobile terminal. |
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