Passive Infrared Micro-Gesture Sensing for Low-Power Wearables

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Solution Overview

Problem

Existing gesture recognition systems face challenges in accurately tracking fine-grained or micro-gestures due to their small magnitude and frequent self-occlusion, and existing solutions like magnetic sensing and millimeter-wave radar face issues with energy consumption, particularly in wearable devices.

Innovation Solution

The use of passive infrared (PIR) sensors to detect micro-gestures by generating a gesture-response signal, which is then processed to extract features and compare them to a control-gesture model, allowing for the recognition of micro-gestures without the need for instrumenting the user with magnets or high-energy sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic sensing is used to track fine-grained gestures, then tracking precision is improved, but device complexity increases due to requiring instrumented fingers with magnets and sensors

Engineering Contradiction:

Improvetracking precisionVSAvoidinstrumentation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces magnetic sensing (which requires mechanical instrumentation of fingers with magnets and sensors) with optical sensing using a camera and machine learning algorithms. This substitution eliminates the need for complex physical instrumentation while maintaining the ability to track fine-grained gestures, directly resolving the contradiction between measurement precision and device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary computational model (machine learning algorithm) that processes ordinary video data to extract fine-grained gesture information. This intermediary approach allows the system to achieve high tracking precision without directly instrumenting the fingers, thereby reducing device complexity while maintaining measurement accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If millimeter-wave radar is used to sense subtle finger movement, then measurement precision is improved, but energy consumption increases

Engineering Contradiction:

Improvedetection precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent uses standard video camera technology (a common, low-cost, low-power component) instead of expensive, high-power millimeter-wave radar. The system processes ordinary video frames that are already being captured by the device's camera, thereby achieving fine-grained gesture detection without the high energy consumption associated with active radar sensing

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a computational model that copies and analyzes the optical patterns already present in standard video data. By training the machine learning algorithm to recognize subtle finger movements from regular video frames, the system achieves radar-level detection precision using only the device's existing low-power camera sensor

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If traditional gestural input methods are used requiring finger or hand movement, then interaction capability is improved, but user fatigue increases over time

Engineering Contradiction:

Improveinteraction capabilityVSAvoiduser fatigue

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of moving object

Solution Approach 1:

The patent enables detection of partial, subtle finger movements (fine-grained gestures) rather than requiring full hand or arm movements. By training the machine learning model to recognize small-scale digit motions and micro-gestures, the system allows users to interact with devices using minimal physical effort, thereby maintaining interaction capability while significantly reducing user fatigue over extended use periods

Inventive Principle:

Principle #16Partial or excessive action

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 enables efficient and accurate recognition of micro-gestures with low power consumption, suitable for wearable devices, reducing fatigue and improving interaction efficiency with devices like smartwatches and augmented reality glasses.

Implementation Method 1

at least one passive infrared (PIR) sensor configured and positioned to define a gesture-sensing region in free space proximate to the at least one PIR sensor

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentUS10608632B2Infrared-based gesture sensing and detection systems, and apparatuses, software, and methods relating to same

Publication Date: 2020.03.31 CARNEGIE MELLON UNIV

AI summary

An infrared (IR)-based gesture sensing and detection system that includes at least one IR sensor for sensing micro gestures of one or more heat-radiating bodies made within a gesture-sensing region located proximate to the IR sensor. Each unique micro gesture may be used as a control gesture for controlling one or more controllable devices. Non-limiting examples of controllable devices include smart wearable device, handheld computing devices, and smart appliances, among many others. In some embodiments, each IR sensor is a passive IR sensor based on a pyroelectric material, and the IR-based gesture sensing and detection system is configured to consume minimal power to operate.