Thermal Sensor Calibration for Gesture Detection

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Solution Overview

Problem

Current gesture detection systems in mobile electronic devices rely on thermal sensors, which are prone to inaccuracies due to variations in room and user hand temperatures, leading to inconsistent gesture recognition across different environments and users.

Innovation Solution

The implementation of additional sensing methods, such as IR-proximity sensors, capacitive sensors, or ultrasonic sensors, to determine hand proximity and calibrate thermal sensor thresholds, ensuring accurate gesture detection by establishing an approximate hand temperature and adjusting detection settings accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If thermal sensors are used for gesture detection, then gesture recognition capability is provided, but measurement accuracy deteriorates due to temperature variations

Engineering Contradiction:

Improvegesture detection capabilityVSAvoidtemperature measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the temperature threshold parameter based on ambient temperature conditions. When ambient temperature changes, the threshold for detecting hand temperature is adjusted accordingly, allowing the gesture detection system to maintain accuracy across different thermal environments rather than using a fixed threshold

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system continuously monitors ambient temperature and uses this feedback to adjust the temperature threshold for gesture detection. This closed-loop approach ensures that the detection criteria adapt to changing environmental conditions, maintaining measurement precision while preserving gesture recognition capability

Inventive Principle:

Principle #23Feedback

2Measurement precision

If thermal sensor threshold is set for one temperature condition, then accurate detection is achieved under that condition, but reliability deteriorates under different temperature conditions

Engineering Contradiction:

Improvedetection accuracy at specific temperatureVSAvoidconsistent detection across temperature variations

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The temperature threshold is transformed from a static, fixed value to a dynamic parameter that automatically adjusts with ambient temperature changes. This allows the system to maintain optimal detection accuracy whether the environment is cold or hot, ensuring reliable gesture recognition across varying temperature conditions

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If distance between sensor and hand affects temperature measurement, then proximity detection sensitivity is improved, but measurement consistency deteriorates

Engineering Contradiction:

Improveproximity detection sensitivityVSAvoidmeasurement consistency across distances

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system adjusts the temperature threshold parameter based on detected hand proximity. When the hand is closer to the sensor, the threshold is modified to account for the increased thermal signal strength, while farther distances use different threshold values. This dynamic parameter adjustment maintains measurement consistency regardless of distance variations

Inventive Principle:

Principle #35Parameter changes

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 accuracy and reliability of gesture recognition by compensating for temperature variations, allowing for consistent and precise user interaction across varying conditions.

Implementation Method 1

thermal sensors are used for presence detection and hand gesture detection. Such sensors work by measuring a temperature difference between the room or ambient temperature and the user's presumably higher hand temperature

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

IR-proximity sensors, capacitive sensors, or ultrasonic sensors, to determine hand proximity

Methodology Applied

Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 3

IR-proximity sensors, capacitive sensors, or ultrasonic sensors, to determine hand proximity

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 4

IR-proximity sensors, capacitive sensors, or ultrasonic sensors, to determine hand proximity

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentUS10649539B1Hand temperature compensation

Publication Date: 2020.05.12 MOTOROLA MOBILITY LLC

AI summary

Systems and methods for calibrating presence and gesture detection thermal sensors in a mobile electronic communications device entail sensing an ambient temperature and designating the sensed ambient temperature as room temperature, and determining that a user appendage has touched, or is close to but not touching, the thermal sensor. If the user appendage has touched a lens of the thermal sensor, a sensed temperature just prior to that event is used as hand temperature. If the user appendage is close to but not touching the lens of the thermal sensor, the temperature during that event is used as hand temperature. A difference between the hand temperature and the room temperature is then determined and the presence and gesture detection functions for the device are calibrated based on the determined difference.