Problem

Over half of falls in older adults are caused by tripping. Many of these trips are caused by small obstacles present on outdoor walkways. The current practice for many municipalities is to repair outdoor walkway tripping hazards that are higher than 6mm, ignoring the rest. There is evidence that older adults are likely to trip on obstacles smaller than this cut-off and we hypothesize that lower obstacles may be just as hazardous, if not more hazardous, for older adults (who tend to have lower foot clearances) because smaller obstacles may be more difficult to see. The existing evidence reporting foot clearance of younger and older adults include only lab-based measurement, many measure foot clearances from participants walking on a treadmill. There are no existing studies that report on measurement of foot clearance of real-world pedestrians.

Goal

To address this gap, our team has been working on technology for measuring foot clearance on outdoor walkways. The aim is to develop a system that can be positioned at ground level next to public walkways to collect video images of a pedestrian’s lower body as they walk by. These images can then be analyzed to determine the minimum distance between the lowest point on the edge of the pedestrian’s shoe, and the ground. This is also known as the minimum foot clearance (MFC).

The technology currently in use is the Dual Camera Foot Clearance Estimation system, which consists of a pair of synchronized cameras for recording pedestrians at foot-level. Supplementary information is captured through 3D scans of the walkway surface, reflective marker stickers applied to the walkway surface, and camera calibration procedures.

This information is then used to place 2D points from the recorded footage within 3D space, allowing for the estimation of real-world MFC values from the recorded video frames. The necessary data processing and analysis is conducted through a custom MFC Finder app, developed by our team.

The benefit of this system is that it can easily collect large amounts of video data quickly from many pedestrians and is designed specifically for outdoor, real-world use. We are currently working on validating this system and using it to conduct outdoor data collection across sidewalk obstacles of differing heights.

Results

This research is currently ongoing and results are not yet available.