Image-Based Occupancy Sensing for Motionless and Multiple People
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Solution Overview
Problem
Ultrasonic motion detectors have limitations such as a limited range, reduced accuracy with distance, and difficulty in detecting multiple occupants or those not exhibiting motion, leading to incorrect occupancy detection in building energy management systems.
Innovation Solution
An image-based occupancy sensor system that processes image signals to generate motion detection, people detection, and face detection signals, integrating these to provide an accurate occupancy indication, including confidence levels, to determine vacancy or occupancy within a monitored volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic motion detectors are used for occupancy detection, then the system is inexpensive and simple to implement, but the detection accuracy deteriorates with increasing distance and motionless occupants cannot be detected
Solution Approach 1:
The patent replaces ultrasonic motion detection (acoustic field) with image-based detection using cameras (optical field). The system uses image processing algorithms to detect occupancy by analyzing visual features such as human shapes, faces, and motion in image sequences, eliminating the distance limitations and motion detection requirements of ultrasonic sensors.
Solution Approach 2:
The system integrates multiple detection functions into a single image-based platform: motion detection, static occupancy detection, multiple occupant counting, and distance-independent detection all occur through processing image data from cameras, providing universal occupancy detection capability across various scenarios.
2Reliability
If ultrasonic motion detectors are used, then the device complexity is low, but the system produces false occupancy indications when occupants are motionless
Solution Approach 1:
The patent combines multiple detection signals (motion detection signal, people detection signal, face detection signal) from different image processing routines into a single integrated occupancy signal. This fusion approach leverages the strengths of each detection method while compensating for individual weaknesses, improving reliability without requiring multiple separate sensor systems.
Solution Approach 2:
The system introduces an image processing intermediary that translates visual information into occupancy signals. The image-based detection acts as a mediator between the physical occupancy state and the control system, providing accurate detection without the limitations of direct ultrasonic motion sensing.
Data Source
AI summary
An image-based occupancy sensor includes a motion detection module that receives and processes an image signal to generate a motion detection signal, a people detection module that receives the image signal and processes the image signal to generate a people detection signal, a face detection module that receives the image signal and processes the image signal to generate a face detection signal, and a sensor integration module that receives the motion detection signal from the motion detection module, receives the people detection signal from the people detection module, receives the face detection signal from the face detection module, and generates an occupancy signal using the motion detection signal, the people detection signal, and the face detection signal, with the occupancy signal indicating vacancy or occupancy, with an occupancy indication specifying that one or more people are detected within the monitored volume.