Impact of parallax and interpupillary distance on size judgment performances of virtual objects in stereoscopic displays

Construction of Virtual Interaction Location Prediction Model Based on Distance Cognition

Due to the difference in distance cognition between virtual and real symmetric space, it is difficult for users to accurately interact with the target in the Digital Twin system. In order to study the cross-effects of interaction task, target size and target location on the accuracy of egocentric peripersonal distance cognition, a 2 × 5 × 9 × 5 asymmetric experiment was designed and carried out. There were two kinds of interaction tasks, five kinds of interaction target widths and nine kinds of spatial locations set to estimate the five egocentric peripersonal distances. Based on the experimental data, with interaction task, target width and the actual spatial location as independent variables and virtual interaction location as a dependent variable, the mapping model between the actual physical location and virtual interaction location of different interaction targets was constructed and evaluated by multiple linear regression method. The results showed that the prediction model constructed by stepwise regression method was simple and less computationally intensive, but it had better stability and prediction ability. The correlation coefficients R2 on xp, yp and zp were 0.994, 0.999 and 0.998, RMSE values were 2.583 cm, 1.0774 cm and 1.3155 cm, rRMSE values were 26.57%, 12.60% and 1.15%, respectively. The research of relevant experiments and the construction of models are helpful to solve the layout optimization problem of virtual interactive space in the Digital Twin system.

Agreement and inter-session repeatability of manual and automatic interpupillary distance measurements

BACKGROUND

Interpupillary distance (IPD) is important in developmental anatomy, genetics, design of optical instrumentation, ocular diagnostics, and optical prescribing. IPD frequently is measured on different days, and by either automatic pupillometers (physiological measurement) or manual ruler (anatomical measurement). Therefore, there is importance in the agreement and inter-session repeatability of manual and automatic IPD measurements.

METHODS

Monocular distance from the bridge of the nose and binocular distance and near binocular IPD were randomly measured, using a millimeter ruler and the Essilor Pupillon pupillometer. Gender effects were assessed using Wilcoxon and Mann-Whitney tests, respectively. Agreement was assessed using Spearman correlation and Bland-Altman (B&A) plots. Thirty additional participants were tested within 1-2 weeks to determine the inter-session repeatability.

RESULTS

The agreement study included 199 participants (mean age: 24.1 ± 5.0 range: 19-53, 58 male, 141 female) and the repeatability sub- study included 30 (mean age: 27.9 ± 4.5, range: 23-39, 6 male, 24 female). Males and females significantly differed in age (<2 year mean difference (md)) and IPD (monocular md: < 1 mm, binocular md: < 2 mm). Manual vs. automatic measurements were significantly different for all conditions (md: <1 mm for all) except for distance left eye male PD. There was no significant difference between the session for both methods.

CONCLUSIONS

Binocular and monocular manual and automatic measurements were significantly different statistically, but not clinically. Distance binocular IPD was approximately 3 mm wider than near IPD. Male binocular IPD was approximately 2 mm wider than the female IPD. Both methods had good inter-session repeatability.