Name: Silver-Multimodal-Dataset
Creator: Silver Avocado

Dataset Overview

The dataset is designed to support the development of machine learning models for detecting daily activities, violence, and fall down scenarios from combined audio and video sources.
The preprocessing pipeline leverages audio feature extraction, human keypoint detection, and relative positional encoding to generate a unified representation for training and inference.
- Classes:
  - 0: Daily - Normal indoor activities
  - 1: Violence - Aggressive behaviors
  - 2: Fall Down - Sudden falls or collapses
- Data Format:
  - Stored as .npy files for efficient loading and processing.
  - Each .npy file is a tensor containing concatenated audio and video feature representations for a fixed sequence of frames.
Data preprocessing code: GitHub data-preprocessing

Dataset Preprocessing Pipeline

The dataset preprocessing consists of a multi-step pipeline to extract and align audio features and video keypoints. Below is a detailed explanation of each step:

WAV File Extraction:
- Audio is extracted from the original video files in WAV format.
Frame Splitting:
- The audio signal is divided into 1/30-second segments to synchronize with video frames.
MFCC Feature Extraction:
- Mel-Frequency Cepstral Coefficients (MFCC) are computed for each audio segment.
- Each MFCC output has a shape of 13 x m, where m represents the number of frames in the audio segment.

YOLO Object Detection:
- Detects up to 3 individuals in each video frame using the YOLO model.
- Outputs bounding boxes for detected individuals.
MediaPipe Keypoint Extraction:
- For each detected individual, MediaPipe extracts 33 keypoints, each represented as (x, y, z, visibility), where:
  - x, y, z : Spatial coordinates.
  - visibility : Confidence score for the detected keypoint.
Keypoint Filtering:
- Keypoints 1, 2, and 3 (eyebrow-specific) are excluded.
- Keypoints are further filtered by visibility threshold(0.5) to ensure reliable data.
- Visibility property is excluded in further calculations.
Relative Positional Encoding:
- For the remaining 30 keypoints, relative positions of the 10 most important keypoints are computed.
- These relative positions are added as additional features to improve context-aware modeling.
Feature Dimensionality Adjustment:
- The output is reshaped to (n, 30*3 + 30, 3), where n is the number of frames.

Expansion:
- Video keypoints are expanded to match the audio feature dimensions, resulting in a tensor of shape (1, 1, 4).
Concatenation:
- Audio (13) and video (12) features are concatenated along the feature axis.
- The final representation has a shape of (n, 120, 13+12), where n is the number of frames.

The final processed data is saved as .npy files, organized into three folders:
- 0_daily/: Contains data representing normal daily activities.
- 1_violence/: Contains data representing violent scenarios.
- 2_fall_down/: Contains data representing falling events.

This dataset provides a comprehensive representation of synchronized audio and video features for real-time activity recognition tasks.
The combination of MFCC audio features and MediaPipe keypoints ensures the model can accurately detect and differentiate between the defined activity classes.
Key Features:
1. Multimodal Representation:
  - Audio and video modalities are fused into a single representation to capture both sound and motion dynamics.
2. Efficient Format:
  - The .npy format ensures fast loading and processing, suitable for large-scale training.
3. Real-World Applications:
  - Designed for safety systems, healthcare monitoring, and smart home applications.
  - Adaptation in SilverAssistant project: HuggingFace Silver-Multimodal Model
This dataset enables the development of robust multimodal models for detecting critical situations with high accuracy and efficiency.