Occupant Detection Sensor Fusion for Minor Motion and Static Objects
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Solution Overview
Problem
Conventional passive infrared (PIR) sensors struggle with accurately detecting motionless objects and determining the direction of movement, leading to unpredictable detection behavior and challenges in applications like desk occupancy and light control due to their large observation area and reliance on motion type and location.
Innovation Solution
A sensor fusion scheme combining a passive infrared (PIR) sensor with a multi-pixel thermopile array and an electromagnetic image sensor to enhance detection reliability by analyzing analogue signal characteristics and object localization, distinguishing between human beings and static objects through distance correlation and thermal distribution analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PIR sensor is used for motion detection, then motion detection capability is provided, but detection reliability deteriorates for motionless objects and minor motions
Solution Approach 1:
The patent combines a PIR sensor with a multi-pixel thermopile array sensor to create a sensor fusion system. The PIR sensor detects motion events while the thermopile array provides high-resolution thermal imaging to distinguish between motionless objects and persons with minor motions, thereby improving overall detection reliability
Solution Approach 2:
The patent introduces an electromagnetic image sensor as an intermediary to capture visual information that complements the thermal data. This intermediary sensor helps disambiguate between different thermal sources by providing additional contextual information about the detected objects
2Area of stationary object
If a PIR sensor with large observation area is used, then coverage is improved, but measurement precision deteriorates for determining object location and motion direction
Solution Approach 1:
The patent segments the observation area into multiple detection zones using the array structure of the thermopile sensor. Each pixel in the thermopile array corresponds to a specific spatial location, enabling precise determination of object position and motion direction within the large observation area while maintaining high measurement precision
3Device complexity
If only PIR sensor data is used for classification, then system complexity is reduced, but detection accuracy deteriorates due to signal noise and inability to distinguish persons from static objects
Solution Approach 1:
The patent uses a composite sensing approach that combines data from two different sensor types (PIR and thermopile array) with complementary characteristics. The PIR sensor provides motion event detection while the thermopile array provides high-resolution thermal imaging, creating a composite data set that enables accurate classification of detected objects as persons or static objects despite individual sensor limitations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the detection of minor motions and enhances the accuracy of occupant tracking by integrating PIR sensor data with image-based object localization, reducing false triggers and improving light control systems.
Implementation Method 1
a passive infrared (PIR) sensor for detecting an object movement and an object distance from the PIR sensor
Implementation Method 2
an electromagnetic image sensor for generating an image of at least a portion of the observation range
Data Source
AI summary
The invention relates to an occupant or presence detection system and method where movement detection of an infrared (IR) sensor device and presence detection of an image sensor device are combined. Information derived from an IR movement detection signal is combined with object locations extracted by the image sensor device to distinguish human beings from static objects and improve occupant or presence detection in various applications, such as light control, desk occupancy and people counting in office applications that use advanced sensing bundles (ASB).