The Underling Mechanism Of Distance Perception Of Avatar In Virtual Environment

Understanding and quantifying the perceived distance in virtual reality(VR)is very important and will help improve the VR fidelity.However,there is no unified conclusion about the accuracy of distance perception in VR so far and most previous studies only present qualitative but not quantitative results.In this study,we conducted three datasets to explore the effect of different VR devices and texture backgrounds on distance perception by using the oral report method and proposed a math function to build the relationship between perceived and actual distance.In Experiment 1,participants estimated the egocentric distance of three virtual targets(avatar,object,animal)via three VR devices(HTC VIVE,Xiaopai,CAVE)respectively in a virtual environment with no texture background.The results showed that different VR devices had a significant influence on the distance estimation.The perceived distance of the CAVE system is closest to the true value,followed by the Xiaopai helmet,and the HTC VIVE is the worst.However,the perceived distance in all VR devices is less than the actual distance,and the ratio of perceived distance to actual distance shows a trend of increasing first and then decreasing as the distance increases.In addition,the virtual target also has a significant effect on distance perception.The accuracy of distance estimation of avatars is higher than that of objects and animals,and the accuracy of distance estimation of objects is higher than that of animals.In Experiment 2,we explored whether adding a checkerboard texture background into the virtual scene improves the accuracy of distance perception.Experimental data showed that the perceived distance under the checkerboard texture background increases as compared to that under no texture background.However,subjects overestimated the distance of the avatar.In one public data,the researchers compared the estimated distance of human beings or avatars in real and virtual environments with similar grass texture background.The data showed that the subjects overestimated the distance no matter in the real or in the virtual environment,which is consistent with the results of experiment 2.This result suggested that the distance overestimation is due to the error of verbal reporting and the texture background improves the accuracy of distance perception in VR.Finally,we fit the experimental data of different texture backgrounds and different distance very well through the ? growth and extinction function.To sum up,this study investigated the effects of different VR devices and textures on distance perception in detail.Our function provides an effective method to quantify the perceived distance and a valuable guide to researchers for distance correction in VR.