Foot Lifting Detection Using Pressure Threshold Segmentation
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Solution Overview
Problem
Existing gait rehabilitation methods face challenges in accurately and reliably detecting the lifting of a foot, particularly for patients with impaired gait, which is crucial for timing electrical stimulation and analysis.
Innovation Solution
A method and device using pressure sensors beneath the foot to continuously receive and process signals, assigning states based on pressure thresholds to determine when a foot is lifted, with priority comparison between sensors to ensure accurate detection, even for patients with impaired gait.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensors continuously monitor pressure values to detect foot lifting, then detection reliability is improved, but device complexity increases due to continuous signal processing and threshold comparison requirements
Solution Approach 1:
The detection process is segmented into distinct operational phases: a prepared state where pressure exceeds an upper threshold for a duration longer than a first time threshold, and a detection state where pressure falls below a lower threshold. This segmentation allows the system to process signals in discrete, manageable stages rather than continuous complex analysis, improving reliability while controlling complexity.
Solution Approach 2:
The system enters a prepared state before actual foot lifting occurs, when pressure remains above the upper threshold for the required duration. This preliminary action prepares the system in advance, so that when pressure drops below the lower threshold, the foot lifting detection can be immediately confirmed without complex real-time analysis, thus improving reliability without proportionally increasing processing complexity.
2Measurement precision
If multiple pressure sensors are used to improve detection accuracy, then measurement precision is improved, but device complexity increases due to priority comparison logic between sensors
Solution Approach 1:
Each pressure sensor is assigned a specific priority level (first priority, second priority, etc.), creating local quality differences in the sensor array. When multiple sensors detect pressure changes, the system evaluates them according to their assigned priorities, allowing accurate detection of foot lifting while managing the complexity of coordinating multiple sensors through a structured priority-based evaluation framework.
3Reliability
If time thresholds are implemented to filter false detections, then detection reliability is improved, but loss of time occurs due to waiting for threshold duration conditions
Solution Approach 1:
The system requires pressure to exceed the upper threshold for a duration longer than a first time threshold before entering the prepared state. This preliminary time-based verification filters out transient false signals. The loss of time is minimized because once the prepared state is reached, the actual foot lifting detection occurs immediately when pressure drops below the lower threshold, without requiring additional waiting periods.
Data Source
AI summary
A method in gait rehabilitation for detecting a foot being lifted comprises: receiving (102) a plurality of signals from respective pressure sensors (12), mounted beneath a foot of a person, each signal providing a time sequence of values representing asserted pressure; processing the received signals, wherein said processing comprises, for each signal, assigning states to the respective pressure sensor (12) for determining when the foot is being lifted for walking, and wherein said assigning of states comprises: identifying that the sequence of values are maintained above an upper threshold (32) for a duration exceeding a time threshold (36); and upon such identifying assigning a prepared state to the sensor (12); and, when the sensor (12) is in the prepared state, identifying (108) a value below a lower threshold (34) indicating that the foot is potentially lifted; and upon such identifying assigning an unprepared state to the sensor (12); and wherein said processing further comprises, when assigning an unprepared state to a first sensor, determining (110) whether a prepared state is assigned to a second sensor and comparing (112) a priority of the first sensor and the second sensor.