Visual-Inertial Odometry

A computer vision technique that combines camera imagery with motion sensor data (accelerometer and gyroscope) to track a device's position and orientation in 3D space. In accessibility applications, VIO enables smartphones to maintain awareness of object positions even when they move out of the camera's field of view—critical for hand guidance systems where users may tilt or move the phone while reaching for objects. Apple's ARKit and Google's ARCore use VIO to enable augmented reality features without requiring external tracking hardware.