PIR Array Virtual Beam Velocity Detection
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Solution Overview
Problem
Existing motion sensing technologies, such as infrared beam-based systems and passive infrared (PIR) sensors, face issues with accuracy, power efficiency, cost, and safety, particularly in determining spatial gait parameters in home environments, as they can be inaccurate, expensive, power inefficient, and potentially hazardous.
Innovation Solution
The use of passive infrared sensors with angled fields of view to create virtual sensing beams, allowing for precise detection of motion within a controlled, uniform area by defining virtual beams that are parallel to the edges of the sensors, thereby increasing accuracy and reducing false triggers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single PIR sensor with downward facing wedge shaped field of view is used, then the device complexity is low, but the measurement precision of velocity is poor due to spread over distance and imprecise geometry
Solution Approach 1:
The patent divides a single sensor's field of view into multiple virtual sensing beams by segmenting the lateral field of view into discrete edges. Each edge defines a separate virtual beam, allowing the system to treat one physical sensor as multiple virtual sensors. This segmentation enables precise velocity measurement through multiple distinct sensing zones without requiring multiple physical sensors.
Solution Approach 2:
The patent transitions from a single three-dimensional wedge-shaped field of view to multiple two-dimensional virtual sensing beams by utilizing the lateral dimension of the sensor's field of view. By defining edges along the lateral axis and creating parallel virtual beams, the system adds dimensional precision to velocity measurement while maintaining a single physical sensor.
2Use of energy by moving object
If PIR sensors are used to detect motion, then power consumption is reduced compared to active infrared beam systems, but accuracy deteriorates due to inherent PIR sensor limitations
Solution Approach 1:
The patent changes the geometric parameters of the sensing field by defining multiple virtual beams with specific lateral edges and angles. This parameter transformation converts the inherent limitation of a single wedge-shaped field into an advantage by creating multiple precisely-defined sensing zones that improve measurement accuracy while maintaining passive operation.
Solution Approach 2:
The patent introduces virtual sensing beams as an intermediary concept between the physical PIR sensor and the velocity measurement process. These virtual beams act as computational constructs that refine the raw sensor data into precise velocity measurements by defining specific geometric paths and edges through which motion is analyzed.
3Measurement precision
If active infrared beam-based systems are used for velocity detection, then measurement precision can be improved, but power consumption increases and the systems become expensive
Solution Approach 1:
The patent creates virtual copies of sensing beams through computational processing of a single PIR sensor's field of view. By defining multiple virtual beams from one physical sensor, the system replicates the functionality of multiple active sensors without the associated power consumption and cost, achieving similar measurement precision through software-based beam segmentation.
Solution Approach 2:
The patent replaces the mechanical/optical active infrared beam system with a passive PIR sensor combined with virtual beam computation. This substitution eliminates the need for active energy emission while achieving comparable or superior measurement precision through geometric processing of passive thermal detection data.
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
This approach enhances the reliability and accuracy of motion sensing by creating a tightly controlled sensing area that avoids irrelevant areas, such as doors, and improves the precision of velocity measurements, making it suitable for household use without the need for complex installations or expensive modifications.
Implementation Method 1
Existing techniques for measuring the velocity of a human in a home can be inaccurate, expensive, power inefficient, damaging to the installation structure, and potentially hazardous. For example, active solutions such as infrared beam-based systems can be power inefficient.
Data Source
AI summary
Methods and systems may include a system including a first passive motion sensor having a lateral field of view with a first edge and a second passive motion sensor having a lateral field of view with a second edge that is substantially parallel to the first edge. The first and second edges can define a virtual beam. The system may also include logic to receive signals from the first and second passive motion sensors and determine a gait velocity and level of activity based on the signals from the first and second passive motion sensors.