Periocular Image Correction for Biometric Recognition with Glasses

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Solution Overview

Problem

Biometric face recognition systems face challenges in identifying individuals wearing glasses, especially when automated, due to distortion caused by spectacle lenses, and also struggle with obscured facial areas, leading to increased computational effort and decreased accuracy.

Innovation Solution

A device and method that use a camera and image processing to detect the periocular region, account for distortion caused by glasses, and generate a spectacle-free image of the eyes, allowing for reliable identification without removing glasses, by detecting pixels away from the spectacle edge and applying a rule to correct optical effects, and optionally using additional cameras for improved image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If glasses are worn during identification, then the person can maintain natural appearance and comfort, but biometric recognition accuracy deteriorates due to lens distortion

Engineering Contradiction:
Improvecomfort during identificationVSAvoidbiometric recognition accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the face image into multiple regions, specifically identifying and isolating the periocular region (area around the eyes) from the rest of the face. By focusing only on this specific segment and excluding the spectacle lenses and frames from the biometric analysis, the system maintains recognition accuracy while allowing the person to wear glasses comfortably.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts and removes the distorted regions caused by spectacle lenses from the biometric analysis. By taking out the affected areas (lenses and frames) and relying solely on the undistorted periocular region for identification, the system eliminates the negative impact of glass wear on recognition accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the entire face is analyzed for biometric features, then comprehensive identification is achieved, but computational effort increases

Engineering Contradiction:
Improveidentification completenessVSAvoidcomputational effort
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential periocular region for biometric analysis, removing unnecessary portions of the face that would increase computational load. This extraction approach maintains reliable identification by focusing on stable, distinctive features while significantly reducing the amount of data to be processed.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the full face image to isolate only the periocular region for analysis. By dividing the face into relevant and irrelevant portions and processing only the relevant segment, the system achieves reliable identification with reduced computational effort compared to analyzing the entire face.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If facial areas are obscured by masks or other coverings, then protection or privacy is maintained, but complete face detection becomes difficult

Engineering Contradiction:
Improveprotection from pathogensVSAvoidface detection difficulty
Core Design Contradiction:
Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

The patent extracts the detectable periocular region from the partially obscured face image. By focusing on the visible area around the eyes that remains accessible even when other facial regions are covered by masks or protectors, the system maintains identification capability while allowing protective coverings to remain in place.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables accurate identification of individuals wearing glasses and those with obscured facial areas, reducing computational effort and ensuring reliable access control without requiring users to remove their glasses.

Implementation Method 1

a camera (101) for detecting the periocular region (104) of the person

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

detect those pixels in the course of the facial train which correspond to a distortion of the facial train caused by the spectacle lens

Methodology Applied
Scientific EffectOptical refraction: Refraction

Data Source

PatentEP3944139A1Device and method for generating a spectacle glass-free or spectacle-free image of a periocular region of a bespectacled person
Publication Date: 2022.01.26 BUNDESDRUCKEREI GMBH
  • EP3944139A1 patent drawingFigure 1
  • EP3944139A1 patent drawingFigure 2
  • EP3944139A1 patent drawingFigure 3

AI summary

The invention relates to a device (100) for generating a spectacle-free image of a periocular region (104) of a person wearing spectacles, comprising a camera (101) for capturing the periocular region (104) of the person, and an evaluation unit (102) connected to the camera (101), which is configured, by means of the image supplied by the camera (101), to identify pixels of a gradient (115a, 115b, 115c, 115d) of at least one facial feature (115) located in the periocular region (104) of the person wearing spectacles away from the rim of the spectacles (116) and away from a spectacle lens (114), and to capture those pixels in the gradient (115a, 115b, 115c, 115d) of the facial feature (115) that are subject to a distortion of the facial feature caused by the spectacle lens (114). (115) correspond to deriving or applying at least one rule from the sequence (115a, 115b, 115c, 115d) of the recorded pixels,and subsequently to shift all pixels contained in the area of ​​the spectacle lens (114) according to the determined or applied rule such that the spectacle-free image of the periocular region (104) is created. The invention also relates to a corresponding method, an access control, and a method for granting or denying access.