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. 2020 Jul 18:8:e00126.
doi: 10.1016/j.ohx.2020.e00126. eCollection 2020 Oct.

Electronic system for step width estimation using programmable system-on-chip technology and time of flight cameras

Yamir H Bolaños  1 , Carlos F Rengifo  2 , Pablo E Caicedo  1 , Luis E Rodriguez  3 , Wilson A Sierra  3
Affiliations

Electronic system for step width estimation using programmable system-on-chip technology and time of flight cameras

Yamir H Bolaños et al. HardwareX. .

Abstract

This paper proposes a low-cost portable electronic system for estimating step width during the human gait cycle. This device, intended to support the Walking Stance item of the fall risk assessment test Performance Oriented Mobility Assessment (POMA), contains three electronic boards, comprising two sensing nodes and a concentrator. Each sensing node contains a force sensitive resistor (FSR) and time-of-flight camera (TOF). Each FSR is placed inside the subject's shoe, while each TOF camera is located at the back of their foot. The FSR detects contact between heel and ground, and the TOF measures the distance to a barrier located on the right side of the walking path. Step width is calculated as the difference between the TOF measurements. After the walk is complete, the information obtained by the FSRs and TOFs is sent via a 433 MHz wireless communication to the concentrator board, which is connected to the USB port of a personal computer (PC). The proposed step width measurement system was validated with an infrared based motion capture (Vicon Corp.), giving an error equal to 11.4% ± 5.5%.

Keywords: Human gait; Motion capture; POMA test; Programming system on chip; Step width; Time-of-flight camera.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

None
Graphical abstract
Fig. 1
Fig. 1
Step width definition.
Fig. 2
Fig. 2
System architecture.
Fig. 3
Fig. 3
Working principle used to estimate step width.
Fig. 4
Fig. 4
PCB layout of 6 cm × 4 cm. Image generated with Autodesk Eagle Freeware Version.
Fig. 5
Fig. 5
Schematic for sensor node device.
Fig. 6
Fig. 6
Components of the sensing node.
Fig. 7
Fig. 7
Side barrier installation.
Fig. 8
Fig. 8
Location of the sensing nodes and the TOF cameras.
Fig. 9
Fig. 9
Concentrator node and connections to PC.
Fig. 10
Fig. 10
User interface developed in Visual C++.
Fig. 11
Fig. 11
The proposed system in operation.
Fig. 12
Fig. 12
Green circles indicate the distance measured by the left TOF camera. These measurements correspond to the local maxima of the FSR (blue circles).
Fig. 13
Fig. 13
Green circles indicate the distance measured by the right TOF camera. The measurements correspond to the local maxima of the FSR (blue circles).
See this image and copyright information in PMC

References

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