Wearable Ego-Motion Tracking for Blind Navigation in Indoor Environments

Abstract

This paper proposes an ego-motion tracking method that utilizes visual-inertial sensors for wearable blind navigation. The unique challenge of wearable motion tracking is to cope with arbitrary body motion and complex environmental dynamics. We introduce a visual sanity check to select accurate visual estimations by comparing visually estimated rotation with measured rotation by a gyroscope. The movement trajectory is recovered through adaptive fusion of visual estimations and inertial measurements, where the visual estimation outputs motion transformation between consecutive image captures, and inertial sensors measure translational acceleration and angular velocities. The frame rates of visual and inertial sensors are different, and vary with respect to time owning to visual sanity checks. We hence employ a multirate extended Kalman filter (EKF) to fuse visual and inertial estimations. The proposed method was tested in different indoor environments, and the results show its effectiveness and accuracy in ego-motion tracking. Note to Practitioners-This paper was motivated by the necessary mobility needs of visually impaired and blind people.According to a review, the top listed accidents they experienced were head-level collision and motion collision, even though they were using assistive devices. Currently, assistive devices are available to emulate missed functions due to vision loss, such as text reading, object recognition, and knee-level obstacle avoidance (e.g., smart canes), but they do not provide the solution to the fundamental problems as raised in the review. The research team is developing a wearable blind navigator based on Google Glass. The target function modules include traversable region detection, motion estimation, and scene dynamics analysis. The ego-motion estimation method presented in this paper is part of the motion estimation module. The experiments on real scenarios suggest that this approach is feasible and effective. In future research, we will address the problems of robustness and real-time performance in system implementation.

Blind MuseumTourer: A System for Self-Guided Tours in Museums and Blind Indoor Navigation

“…Reference [48] proposes an ego-motion tracking method that utilizes Google Glass visual and inertial sensors for wearable blind navigation. The authors introduce a visual sanity check to select accurate visual estimations by comparing visually-estimated rotation with measured rotation by a gyroscope.…”

Robust orientation estimate via inertial guided visual sample consensus

“…Visual-inertial orientation system employs IMU [17,18] to assist camera in achieving pose estimation. Hardegger et al [1] fused the foot-mounted inertial measurements with visual local landmark map in the particle filter framework for 3D Action SLAM in the indoor scenarios.…”

Smart-Glasses: Exposing and Elucidating the Ethical Issues

“…Block unpleasant experiences and avoid anxiety (in a hospital setting) (Tse et al 2002) and to support patients with specific needs (of care) (Hetterich et al 2014) Psychological and health risks with smartglasses have been pointed out (Jacquemard et al 2014) Making learning more efficient or create new learning modes (Koper 2014). However, the outcomes of learning with smart-glasses are mixed (Sapargaliyev 2015) Safety aspects are also identified in the use of smart-glasses, e.g., in (pervasive) gaming (Valente et al 2015) or navigation (Jones 2014) Provide safety and security, e.g., for persons with various forms of impairment, such as detecting hazards for persons with visual impairment (He et al 2015), or in the industry (Neira Millan 2013) Smart-glasses are envisioned to threaten security (Boissier and Castelfranchi 2015) as information about a person and his or her behavior may become accessible by others (Nyang et al 2014). Smart-glasses may increase situational awareness (Ackerman 2012), multitasking abilities (Nikolov 2013), and orientation (Muschiol 2015) May make people dependent (Bendel 2014) Assist recognizing and remembering (Iwamura et al 2014) as well as impede forgetting (Jacquemard et al 2014) Psychological and health risks with smartglasses have been pointed out (Jacquemard et al 2014) Be a valuable extension of the human brain (Bendel 2014) and predicting cognitive states (Henderson et al 2013) Safety aspects are also identified in the use of smart-glasses, e.g., in (pervasive) gaming (Valente et al 2015) or navigation (Jones 2014) Increase power through the aggregation of data, e.g., images (Bendel 2014).…”

“…Potential exploitation and steering (Borean et al 2015), leak of sensitive information (Shen et al 2015) Compensate for impaired functions, such as landmark identification for persons with reduced visual ability (Ugulino and Fuks 2015) increasing their quality of life (He et al 2015) Breach Negative reactions (verbally or physical) by people in public spaces (Wolf et al 2014). Provide evidence and facilitate litigation (Bergman 2013) May reduce some cognitive capacities as they are "outsourced" to technology, e.g., navigation skills, or delegate crucial tasks to less skilled personnel.…”