基于菲茨定律的虚拟现实任意形状选择模型

为了评估虚拟现实（VR）交互界面不同图形设计的点击效率，基于概率菲茨定律提出一种针对虚拟现实情境下指向性任务完成时间的预测方法，并构建了VR任意形状选择模型。首先，根据VR界面设计的实际需求，加入形状对指向性任务完成时间的影响，构建命中概率与任务难度指数的关系函数，将目标质心设为待积分函数的中心点，完成虚拟情境下概率菲茨模型定义。然后，设计实验一以获取改进概率菲茨模型中概率函数的常数项值；在此基础上设计实验二计算改进概率菲茨模型中预测函数的常数项，完成改进概率菲茨模型的构建。最后，以某VR烟草分拣系统实际点击任务对模型进行验证与评估，实验结果表明该模型能够在虚拟情境下对任务完成时间进行良好预测。

Virtual reality arbitrary shape selection model based on Fitts' law

To evaluate the click efficiency of different graphic designs of Virtual Reality (VR) interactive interface, a prediction method for the completion time of directional tasks in virtual scenarios was proposed based on probabilistic Fitts' law, and an arbitrary shape selection model of VR was constructed. First, according to the actual needs of VR interface design, the influence of shape on the completion time of directional tasks was added, a relation function between hit probability and task difficulty index was constructed, the target centroid was set as the center point of the function to be integrated, and the definition of probabilistic Fitts' model under the virtual scenario was completed. Then, the first experiment was designed to obtain the constant term value of the probability function in the improved probabilistic Fitts' model. On this basis, the second experiment was designed to calculate the constant term of the prediction function in the improved probabilistic Fitts' model, so as to construct the improved probabilistic Fitts' model. Finally, the model was verified and evaluated on the actual click tasks in a VR tobacco sorting system. Experimental results show that the model can predict the task completion time in the virtual scenario.