Sleep Posture Detection Using Thermal Turnover Events
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Solution Overview
Problem
Existing sleep posture monitoring technologies face challenges due to privacy concerns with camera-based systems, obtrusiveness of wearable accelerometers, high deployment costs of bedsheet-embedded pressure sensors, and limited accuracy of simple sensors like Single Pixel Thermopiles and PIRs, making it difficult to accurately monitor sleep postures.
Innovation Solution
A system utilizing low-cost sensors such as Single Pixel Thermopiles (SPT) and PIRs to detect transition events between sleep postures by measuring temperature signals, combined with machine learning models to determine sleep postures, and selecting optimal sensor placements based on field of view to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based systems are used for sleep posture monitoring, then measurement precision is improved, but privacy concerns and legal considerations arise
Solution Approach 1:
The patent replaces camera-based optical systems with thermal sensing systems (pyroelectric sensors) that detect heat signatures and temperature changes. This substitution maintains the ability to monitor sleep postures through thermal patterns while eliminating privacy intrusion associated with visual recording, as thermal sensors only detect heat emissions without capturing identifiable visual information.
Solution Approach 2:
The patent introduces thermal energy as an intermediary medium between the user and the monitoring system. Instead of directly observing the user with cameras, the system detects thermal radiation emitted by the body, using heat as a mediator to convey posture information without requiring visual access to the user.
2Measurement precision
If accelerometer-based wearable sensors are used, then measurement precision is improved, but the sensors become obtrusive for the user
Solution Approach 1:
The patent replaces mechanical accelerometer sensors with thermal/pyroelectric sensing systems. Instead of measuring motion through mechanical acceleration forces, the system detects temperature changes and thermal radiation patterns caused by body movements, thereby eliminating the need for wearable devices and improving user comfort.
Solution Approach 2:
The patent creates a thermal copy or representation of the user's motion patterns by detecting temperature changes associated with movement. Rather than directly measuring mechanical acceleration, the system captures thermal signatures that replicate motion information, allowing indirect measurement without physical contact.
3Measurement precision
If pressure sensors embedded in bedsheets are used, then measurement precision is improved, but deployment cost increases
Solution Approach 1:
The patent employs low-cost pyroelectric infrared sensor modules that are inexpensive compared to pressure sensor arrays. These sensors can be easily manufactured and deployed without requiring complex integration into bedsheets, significantly reducing deployment costs while maintaining adequate functionality for sleep posture monitoring.
Solution Approach 2:
The patent replaces expensive pressure-sensitive mechanical sensor arrays with thermal radiation detection systems. By detecting infrared radiation and temperature changes rather than mechanical pressure, the system achieves posture monitoring capability using simpler, less expensive sensor technology.
4Ease of manufacture
If simple sensors like Single Pixel Thermopile are used, then cost is reduced, but measurement precision and accuracy deteriorate
Solution Approach 1:
The patent divides the monitoring task into segments: using multiple simple pyroelectric sensors positioned at different locations to detect different aspects of thermal patterns. By combining data from multiple low-cost sensors strategically placed around the sleeping area, the system achieves comprehensive posture detection accuracy that compensates for the limitations of individual simple sensors.
Solution Approach 2:
The patent transitions from single-point temperature measurement to spatial thermal pattern analysis by positioning sensors at multiple locations. This adds a spatial dimension to the detection, allowing the system to infer posture information from the distribution and pattern of thermal signatures across multiple sensor readings, thereby improving accuracy beyond what single sensors can provide.
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
The system provides accurate and cost-effective monitoring of sleep postures by detecting transition events, reducing thermal interference, and minimizing computational resources while offering alerts for undesirable postures and improving sleep quality assessment.
Implementation Method 1
The one or more sensors comprise Single Pixel Thermopile (SPT), wherein each single pixel thermopile sensor from the one or more sensors is configured to measure a temperature signal in its respective Field-of-View indicative of a motion of the user
Implementation Method 2
time-series signals from SPT sensors may be used to detect the (turning body) motion associated with such transition (tumover) events associating transitions between the different reference sleep postures
Data Source
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AI summary
A system for determining a sleep posture of a user during a sleep session, the system comprising: one or more sensors from a plurality of sensors configured to measure a signal indicative of a motion of the user; and a controller configured to receive the signals from the one or more sensors indicative of a motion of the user; determine a turnover event from a predetermined plurality of reference turnover events based on the received signal; determine the sleep posture of the user from a predetermined plurality of reference sleep postures based on the turnover events.