Glance Sensor Positioning for Mobile Terminal Face Recognition

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Solution Overview

Problem

Existing face recognition technologies in mobile terminals face challenges such as reduced recognition rates with varying skin colors and lighting conditions, vulnerability to spurious photographs due to the need for specific user actions, and high power consumption and noise interference in voice recognition methods.

Innovation Solution

A method for setting an optimal disposition of a glance sensor in a mobile terminal, using metadata from both a front camera and the glance sensor to enhance face recognition security and convenience, where the glance sensor is tilted and positioned adjacent to the front camera to maximize the overlap area for efficient user authentication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If face recognition is performed using skin color of face, then user authentication can be performed in non-contact manner, but recognition rate is reduced when various skin colors and lighting conditions change

Engineering Contradiction:
Improvenon-contact authenticationVSAvoidrecognition rate
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from 2D skin color analysis to 3D facial structure analysis by introducing a glance sensor that captures depth information. This dimensional change enables recognition based on geometric features rather than color, resolving the contradiction between non-contact operation and recognition accuracy under varying conditions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the recognition parameter from skin color (2D optical property) to facial depth structure (3D geometric property). By using a glance sensor to capture time-of-flight data, the system switches to parameters that are invariant to lighting and skin color variations, maintaining both non-contact operation and high recognition rates.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If specific user action such as winking or smiling is induced for face recognition, then security against spurious photograph is high, but convenience is reduced and security is vulnerable since action can be recorded

Engineering Contradiction:
Improvesecurity against spurious photographVSAvoidconvenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary 3D facial structure capture and analysis before authentication is completed. By pre-establishing the user's facial geometry model and comparing it in real-time, the system provides continuous security verification without requiring additional user actions, thus maintaining both security and convenience.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces 3D facial structure data as an intermediary between the user and the authentication system. This intermediary provides continuous verification through depth mapping, eliminating the need for discrete action-based challenges while maintaining high security against photograph attacks.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If camera and microphone are used for face and voice recognition, then recognition can be performed, but power consumption is high and voice recognition rate is reduced by external noise

Engineering Contradiction:
Improverecognition capabilityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and utilizes the infrared illumination source and time-of-flight sensing capability from the glance sensor, separating this function from traditional camera-microphone-based recognition. This extraction enables low-power 3D facial recognition that is immune to external noise, reducing both power consumption and noise vulnerability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the acoustic field-based voice recognition (microphone) with optical field-based time-of-flight measurement (glance sensor). This substitution eliminates susceptibility to external noise and reduces power consumption by using infrared LED illumination combined with TOF sensing rather than continuous audio processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reinforces security and convenience by allowing user authentication through gazing at the front camera without additional actions, enabling quicker and more accurate face recognition.

Implementation Method 1

a glance sensor tilted by a certain angle and disposed adjacent to the front camera to obtain metadata of the 2D face image

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3438873B1Mobile terminal
Publication Date: 2019.11.13 LG ELECTRONICS INC
  • EP3438873B1 patent drawingFigure 1A
  • EP3438873B1 patent drawingFigure 1B~1C
  • EP3438873B1 patent drawingFigure 2~3

AI summary

Disclosed is a mobile terminal. The mobile terminal may include a front camera obtaining a 2D face image of a user, a glance sensor tilted by a certain angle and disposed adjacent to the front camera to obtain metadata of the 2D face image, and a controller obtaining a distance between the glance sensor and the front camera, the distance enabling an area of an overlap region, where a first region representing a range photographable by the front camera overlaps a second region representing a range photographable by the glance sensor, to be the maximum.