Stereoscopic Imaging for Non-Invasive Corneal Measurement

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Solution Overview

Problem

Current methods for measuring the cornea's mechanical, geometric, and dynamic properties are limited to one- or two-dimensional analyses, which are not precise enough for clinical needs, and involve invasive techniques like strong air puffs, leading to discomfort and variability in intraocular pressure measurements.

Innovation Solution

A device using a high-speed stereoscopic imaging system with a micro-air pulse generator and digital image correlation to obtain three-dimensional dynamic measurements of the cornea without invasive stimulation, allowing for precise analysis of mechanical and geometric parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strong air puff stimulation is used to measure corneal mechanical properties, then measurement capability is achieved, but patient comfort deteriorates and measurement variability increases

Engineering Contradiction:
Improvecorneal mechanical properties measurementVSAvoidpatient discomfort and measurement variability
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the strong mechanical air puff stimulation with a non-invasive optical measurement system using high-speed stereoscopic imaging. The system captures corneal deformation under physiological conditions without applying external mechanical forces, thereby eliminating patient discomfort and measurement variability caused by invasive stimulation.

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

Solution Approach 2:

The patent introduces an intermediary optical system (projectors and cameras) that indirectly measures corneal mechanical properties through optical patterns and image correlation, rather than directly applying mechanical force. This intermediary approach allows measurement of mechanical properties without the harmful effects of direct mechanical stimulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If one- or two-dimensional analysis methods are used, then device complexity is reduced, but measurement precision of corneal properties deteriorates

Engineering Contradiction:
Improvecorneal geometric and dynamic propertiesVSAvoidimaging and measurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from one- or two-dimensional analysis to three-dimensional dynamic analysis by employing stereoscopic imaging with multiple cameras. This dimensional upgrade enables precise measurement of corneal geometric and dynamic properties in three dimensions, capturing the full complexity of corneal behavior without requiring overly complex additional systems.

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

Solution Approach 2:

The patent creates a multi-functional system where the same high-speed stereoscopic imaging setup serves multiple purposes: geometric measurement, dynamic analysis, and mechanical property assessment. This universal approach achieves high measurement precision across multiple parameters without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If high-speed stereoscopic imaging with digital image correlation is used, then three-dimensional measurement precision is improved, but device complexity and processing requirements increase

Engineering Contradiction:
Improvethree-dimensional corneal measurementsVSAvoidimaging system and image processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary calibration procedures to establish camera geometry and projection patterns before actual measurements. This preliminary setup creates a standardized framework that simplifies subsequent measurements and reduces processing complexity during actual use, enabling high precision three-dimensional measurements without excessive ongoing computational burden.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses digital image correlation that works with optical copies (images) of the cornea rather than direct physical measurement. This copying approach allows three-dimensional reconstruction from two-dimensional images, achieving high measurement precision while avoiding the need for physically complex measurement apparatus.

Inventive Principle:
Principle #26Copying

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 immediate, non-invasive, high-resolution three-dimensional analysis of the cornea's mechanical and geometric properties, reducing variability and improving the accuracy of intraocular pressure measurements, suitable for diagnosing and treating ocular pathologies like keratoconus and glaucoma.

Implementation Method 1

a high-speed stereoscopic imaging system configured for obtaining at least one image of the random infrared illumination pattern projected onto the entire surface of the second optical region

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the processor is configured for generating a final image with three-dimensional information about the entire extension of the second optical region using a superposition, by means of digital image correlation, of the images obtained by means of the high-speed stereoscopic imaging system

Methodology Applied
Scientific EffectDigital image correlation: Image Processing

Data Source

PatentEP3714765B1Device and method for obtaining mechanical, geometric, and dynamic measurements of optical surfaces
Publication Date: 2021.12.29 FUNDACION INST DE INVESTIGACION SANITARIA FUNDACION JIMENEZ DIAZ
  • EP3714765B1 patent drawingFigure 1
  • EP3714765B1 patent drawingFigure 2
  • EP3714765B1 patent drawingFigure 3

AI summary

The present invention relates to a device and method for obtaining mechanical, geometric, and dynamic measurements of optical surfaces, wherein the device comprises: a high-speed stereoscopic imaging system (1); a spatially discrete stimulus generator (2) for generating spatially discrete stimuli on a first optical region (5) and/or on a second optical region (6); a first projector (3) for projecting a random infrared illumination pattern (7) onto the second optical region (6); a second projector (4) for projecting a slotted illumination pattern onto a central area of the second optical region (6); a processor (10) configured for calibrating the high-speed stereoscopic imaging system (1); wherein the high-speed stereoscopic imaging system (1) is configured for obtaining at least one image of the random infrared illumination pattern (7), as well as of the slotted illumination pattern before, during, and after the application of the spatially discrete stimulus (8).