Head-Mountable Eye Movement Camera System for Objective Saccade Detection

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Solution Overview

Problem

Current eye movement measurement techniques in ophthalmologic, vestibular, and neurologic tests rely on subjective assessments, which are unreliable and impractical in some environments, and existing objective methods like scleral search coils are cumbersome and expensive.

Innovation Solution

A head-mountable device equipped with a camera system, processing unit, and interface that captures high-frame-rate images of the eyes to detect eye saccades objectively, providing a standardized and reproducible measurement of eye movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If scleral search coils are used for objective eye movement measurement, then measurement reliability is improved, but device complexity and cost increase significantly

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses video cameras to capture images of the eye and creates a digital copy/model of the eye's movement rather than using physical search coils embedded in the sclera. Image processing algorithms analyze the captured images to determine eye position and movement, replacing the complex physical measurement mechanism with a visual copying approach.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical scleral search coil system with an optical imaging system. Instead of mechanically embedding coils in the eye and measuring electrical signals, the system uses video cameras to optically track eye movements, substituting a complex mechanical measurement system with a simpler optical one.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If high frame rate is used to detect fast eye saccades, then measurement precision is improved, but data processing load increases

Engineering Contradiction:

Improveeye saccade detection precisionVSAvoiddata processing load

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential information needed for eye movement detection from the full video frames. Instead of processing all pixel data from high-frame-rate images, the system identifies and tracks specific features (eye position, pupil center) to determine saccade parameters, reducing the processing load while maintaining measurement precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a frame rate that may be higher than strictly necessary for detecting saccades (which last 20-200 ms), but processes only partial information from each frame. This excessive sampling combined with selective processing ensures no saccade is missed while keeping computational requirements manageable.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10206568B2Head mountable device for measuring eye movement

Publication Date: 2019.02.19 NATUS ACQUISITION II LLC

AI summary

A head mountable device for measuring eye movement includes: a camera system comprising a first camera, wherein the camera system is configured to obtain a first set of images of a first eye of a user with a first frame rate and a first resolution; a processing unit configured to process the obtained first set of images and provide a processing unit output based on the first set of images; and an interface connected to the processing unit, for providing a device output based on the processing unit output; wherein the first frame rate is sufficient to allow the processing unit to detect eye saccades of the first eye.