DOI: 10.6084/m9.figshare.28736642
title: Confusion_Matrix_Data.zip

description: This research paper proposes a novel approach for human activity recognition using depth video data, focusing on improving accuracy by effectively capturing motion information and utilizing a robust classification method. Here's a breakdown of the key elements:<b>. Problem Addressed:</b><b>Depth Video-Based Human Activity Recognition:</b> The study tackles the challenge of recognizing human actions using depth videos, which provide distance information rather than traditional color images.<b>2. Proposed Methodology:</b><b>3D Euclidean Space Projection:</b>Each depth frame is converted into a 3D point cloud, representing the human skeleton and its movements in 3D space.This 3D representation is then projected onto three 2D planes: front, side, and top views. This allows for capturing motion from different perspectives.<b>Depth Motion Sequence (DMS):</b>For each of the three views, the absolute difference between consecutive projected images is calculated. This creates a "motion sequence" that highlights changes in depth over time, representing the movement.<b>Space-Time Auto-correlation of Gradients (STACOG) Descriptor:</b>The STACOG descriptor is applied to each DMS. This descriptor extracts features by analyzing the gradients (changes in pixel intensity) within the motion sequence and their spatial-temporal relationships. It aims to capture detailed motion patterns.<b>Feature Vector Combination:</b>The feature vectors obtained from the three views (front, side, top) are concatenated (combined) to create a single, comprehensive feature vector representing the entire action.<b>l2-Regularized Collaborative Representation Classifier (l2-CRC):</b>The l2-CRC algorithm is used for classification. This method represents a test action as a linear combination of training actions. The l2 regularization helps to prevent overfitting and improve robustness. Then the classifier assign the label of the training action that best represent the test action.<b>3. Evaluation and Results:</b><b>Datasets Used:</b>MSR-Action 3D, DHA, and UTD-MHAD: These are standard public datasets used for human activity recognition research, allowing for fair comparison with other methods.<b>Evaluation Metric:</b>Recognition Accuracy: The primary metric used to evaluate the performance of the proposed approach.<b>Comparison with Existing Approaches:</b>The research compares the accuracy of their method with that of other state-of-the-art approaches to demonstrate its superiority.<b>Key Contributions and Significance:</b><b>Effective Motion Representation:</b> The use of 3D projection views and the STACOG descriptor aims to capture motion information more effectively than traditional methods.<b>Robust Classification:</b> The l2-CRC classifier provides a robust and accurate classification framework.<b>Improved Recognition Accuracy:</b> The research demonstrates that the proposed approach achieves higher recognition accuracy compared to existing methods on benchmark datasets.<b>In essence, this research aims to improve the accuracy of depth video-based human activity recognition by extracting more informative motion features and using a powerful classification algorithm.</b>