ToF Presence Detector Adaptive Thresholding
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Solution Overview
Problem
Current Time-of-Flight (ToF) presence detectors often suffer from false positives, failing to distinguish between dormant animate objects, such as stationary humans, and inanimate objects, leading to unnecessary device state changes.
Innovation Solution
A device and method utilizing an optical source and sensor to transmit and receive optical pulses, determining distance parameters to differentiate between macro- and micro-variations in distance, allowing discrimination between stationary inanimate and dormant animate objects by controlling device operation based on thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ToF presence detectors use optical devices to detect objects, then the detector can sense objects without physical contact and determine distance, but it cannot distinguish between dormant animate objects and inanimate objects, leading to false positives
Solution Approach 1:
The system dynamically adjusts the detection threshold and measurement parameters based on the detected signal characteristics. By making the detection system adaptive rather than static, it can distinguish between the subtle movements of dormant animate objects and stationary inanimate objects, resolving the contradiction between reliability and measurement precision.
Solution Approach 2:
The patent changes multiple parameters including optical pulse duration, measurement frequency, and threshold values to optimize detection. By varying these parameters, the system can enhance its ability to detect minute movements while maintaining accurate distinction between animate and inanimate objects, thus improving both reliability and measurement precision.
2Reliability
If the device maintains active state to detect dormant animate objects, then false positives are minimized, but power consumption increases
Solution Approach 1:
The system employs periodic detection cycles with varying intensity rather than continuous high-power operation. During periods of detected stability, it reduces measurement frequency while maintaining alertness to significant changes. This periodic approach maintains reliability for detecting dormant animate objects while significantly reducing overall power consumption compared to continuous active monitoring.
Solution Approach 2:
The patent implements a tiered detection approach where full-power detection is applied only when necessary (upon detecting potential movement or changes in environmental conditions), while baseline monitoring operates at reduced power levels. This partial action strategy ensures false positives are minimized through thorough detection when needed, while conserving energy during stable periods.
3Reliability
If the device uses continuous monitoring to distinguish animate from inanimate objects, then detection reliability improves, but device complexity increases
Solution Approach 1:
The detection process is segmented into multiple stages: initial detection, verification, and classification. Each stage processes only the necessary data with appropriate complexity level. This segmentation allows the system to achieve high classification accuracy through systematic analysis while avoiding the need for continuously complex processing of all sensor data, thus managing device complexity effectively.
Solution Approach 2:
The system performs preliminary analysis of detection signals to identify patterns indicative of animate objects before committing to full classification processing. By conducting preliminary filtering and pattern recognition, it reduces the burden on the main processing system while maintaining high classification accuracy, effectively managing the trade-off between reliability and device complexity.
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 effectively minimizes false positives by detecting small movements, such as human breathing, to maintain device activity with dormant animate objects and conserve power by switching to low-power mode when appropriate, while efficiently managing power consumption.
Implementation Method 1
an optical source configured to transmit an optical pulse and an optical sensor configured to receive a reflection of the optical pulse
Implementation Method 2
a processor configured to determine a parameter based on the reflection, the parameter indicative of a distance between the device and a target
Data Source
AI summary
An embodiment device includes an optical source configured to transmit an optical pulse and an optical sensor configured to receive a reflection of the optical pulse. The device further includes a processor configured to determine a parameter based on the reflection, the parameter indicative of a distance between the device and a target; and a controller configured to generate a first control signal based on the parameter, the first control signal being configured to control an operation of the optical source.