Human Activity Recognition from Knee Angle Using Machine Learning Techniques

TL;DR

This study demonstrates that machine learning algorithms, especially Gradient Boosting, can effectively classify human activities from knee angle data, using a publicly available dataset to improve generalizability and application scope.

Contribution

It introduces a novel approach of using a publicly available pathology dataset and raw knee angle data for activity recognition, comparing multiple ML algorithms and training methods.

Findings

Gradient Boosting achieved up to 0.94 AUC with raw data.

Using publicly available datasets enhances generalizability.

Raw data training outperforms manual feature extraction.

Abstract

Human Activity Recognition (HAR) is a crucial technology for many applications such as smart homes, surveillance, human assistance and health care. This technology utilises pattern recognition and can contribute to the development of human-in-the-loop control of different systems such as orthoses and exoskeletons. The majority of reported studies use a small dataset collected from an experiment for a specific purpose. The downsides of this approach include: 1) it is hard to generalise the outcome to different people with different biomechanical characteristics and health conditions, and 2) it cannot be implemented in applications other than the original experiment. To address these deficiencies, the current study investigates using a publicly available dataset collected for pathology diagnosis purposes to train Machine Learning (ML) algorithms. A dataset containing knee motion of participants performing different exercises has been used to classify human activity. The algorithms used in this study are Gaussian Naive Bayes, Decision Tree, Random Forest, K-Nearest Neighbors Vote, Support Vector Machine and Gradient Boosting. Furthermore, two training approaches are compared to raw data (de-noised) and manually extracted features. The results show up to 0.94 performance of the Area Under the ROC Curve (AUC) metric for 11-fold cross-validation for Gradient Boosting algorithm using raw data. This outcome reflects the validity and potential use of the proposed approach for this type of dataset.