Your Hands Can Tell: Detecting Redirected Hand Movements in Virtual Reality

In-air hand interactions are prevalent in Virtual Reality (VR), and prior studies have shown that manipulating the visual movement of the hand to be different from the actual hand movement, i.e., hand redirection, could create a more immersive and engaging VR experience. However, this manipulation risks degrading task performance and, if maliciously applied, poses a threat to user safety. Such manipulations may arise from VR applications developed with intentional or inadvertent perceptual manipulations that yield harmful outcomes. We advocate for a user’s prerogative to be informed of any such potential manipulations before application usage. To address this, our study introduces an Autoencoder-based anomaly detection technique that leverages users’ inherent hand movements to identify hand redirection, thereby preserving the integrity of application use. Our model is trained on regular (i.e., non-manipulated) hand movement patterns and employs a stochastic thresholding approach for anomaly detection. We validated our method through a technical evaluation involving 21 participants engaged in reaching tasks under manipulated and non-manipulated scenarios. The results demonstrated a high accuracy of hand redirection detection at $93.7\%$, with an F1-score of $93.9\%$.