Event-Camera Ophthalmic Apparatus for Real-Time Face-Movement Detection

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Solution Overview

Problem

Existing ophthalmologic apparatuses struggle to quickly and accurately check for face movement during alignment and ocular information acquisition, leading to potential misalignment, low precision in eye characteristic measurements, and image blurring.

Innovation Solution

An ophthalmologic apparatus equipped with an event camera that captures anterior ocular segment images and outputs event data with luminance changes, allowing real-time monitoring of face movement by extracting inner and outer canthus points to determine face position and movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pupil image detection and face movement checking methods are used, then the system can determine face support status, but it cannot check face movement in real time during alignment and ocular information acquisition

Engineering Contradiction:
Improveface movement detection reliabilityVSAvoidalignment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces conventional frame-based image processing with event camera technology that detects luminance changes asynchronously. This substitution enables real-time face movement detection during alignment without adding time overhead, as the event camera outputs data only when changes occur rather than continuously capturing full frames

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

Solution Approach 2:

The patent introduces an event camera as an intermediary device between the face support system and the control system. This intermediary captures luminance changes at the cornea surface and converts them into event data that indicates face movement, enabling real-time monitoring without disrupting the alignment process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the examinee's face moves during alignment, then the positional relationship adjustment takes longer or fails, but conventional systems cannot detect this movement

Engineering Contradiction:
Improveeye characteristic measurement precisionVSAvoidalignment success rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the event camera continuously monitors luminance changes at the cornea surface and provides real-time movement information to the control system. This feedback loop enables immediate detection of face movement during alignment, allowing the system to adjust or terminate the alignment process before measurement precision deteriorates

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary detection of face movement using the event camera before alignment is completed. By detecting luminance changes and determining face movement in advance, the system can prevent misalignment from occurring, thereby ensuring both alignment success and subsequent measurement precision

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the examinee's face moves during image capture, then image quality deteriorates with blur or flare, but conventional systems cannot prevent this

Engineering Contradiction:
Improveimage qualityVSAvoidimage capture time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent uses the event camera to provide real-time feedback on face movement during image capture. When luminance changes indicate face movement, the system can immediately terminate or pause the capture process, preventing blur or flare while minimizing loss of capture time by only interrupting when necessary

Inventive Principle:
Principle #23Feedback

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 rapid detection of face movement during alignment and ocular information acquisition, ensuring precise eye characteristic measurements and clear image capture by promptly adjusting the optical system and face support.

Implementation Method 1

an event camera that is installed at a position to capture an anterior ocular segment of the subject eye, the event camera being configured to output only event data, in which a luminance change has exceeded a set threshold from pixel data of an image frame

Methodology Applied
Scientific EffectLuminance change detection: Photoelectric Effect

Data Source

PatentEP4623804A1Ophthalmologic apparatus
Publication Date: 2025.10.01 TOPCON CORPORATION
  • EP4623804A1 patent drawingFigure 1
  • EP4623804A1 patent drawingFigure 2
  • EP4623804A1 patent drawingFigure 3

AI summary

An ophthalmologic apparatus (A) includes an optical system (50) that is configured to acquire ocular information of a subject eye (E) of an examinee; a face support (30, 33) that is configured to support a face of the examinee; a controller (60) that is configured to control at least the optical system (50) and the face support (30, 33). The ophthalmologic apparatus (A) further includes an event camera (80) that is installed at a position to capture an anterior ocular segment of the subject eye (E), the event camera (80) being configured to output only event data, in which a luminance change has exceeded a set threshold from pixel data of an image frame of the anterior ocular segment of the subject eye (E), and the event data being output together with information on coordinates and time as output information. The controller (60) includes a face movement monitoring processing portion (64) that is configured to extract inner canthus point (IC) and outer canthus point (OC) of the subject eye (E) by using the output information from the event camera (80) and to monitor a movement of the face of the examinee based on the extracted inner and outer canthus points (IC, OC).