Fall Detection
Accelerometer-Based Detection
Signal Features
import numpy as np
class FallDetector:
def __init__(self, threshold=2.5, window_size=50):
self.threshold = threshold
self.window_size = window_size
def detect_fall(self, accelerometer_data):
maf = np.sqrt(np.sum(accelerometer_data ** 2, axis=1))
window_var = np.array([np.var(maf[i:i+self.window_size])
for i in range(0, len(maf)-self.window_size)])
return np.where(window_var > self.threshold)[0]
def classify_activity(self, features):
if features['magnitude_var'] > 3.0:
return 'fall'
elif features['magnitude_mean'] > 1.5:
return 'walking'
return 'stationary'
Prediction Algorithms
Pre-Fall Detection
Feature Set
| Feature | Description |
|---|---|
| Gait speed | Walking velocity |
| Stride variance | Step consistency |
| Postural sway | Balance measure |
| TUG time | Timed up-and-go |
Alert Systems
Alert Priority
Response Protocol
- Immediate: Automated emergency call
- Delayed: Caregiver notification
- False positive: Learning update