Miniaturized Ocular Videography System for Rodent Eye Tracking

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Solution Overview

Problem

Current methods for recording eye movements in rodents are limited by the need for stable images and lightweight systems that can accurately track eye positions in freely moving animals without interfering with their natural behavior, as existing ocular videography systems are not suitable for small rodents due to size constraints and interference with their vision.

Innovation Solution

A miniaturized ocular videography system with a high-speed camera mounted on the animal's head, using a physical separation of image sensor and decoder to minimize components, infrared illumination to avoid visual interference, and a lightweight cable system for data transfer, allowing for accurate tracking of eye movements in three dimensions without obstructing the animal's field of view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a traditional ocular videography system is used, then eye movement tracking accuracy is improved, but the system size and weight increase making it unsuitable for small rodents

Engineering Contradiction:
Improveeye movement tracking accuracyVSAvoidsystem weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The system is divided into separate functional modules: a head-mounted unit containing only the essential imaging components (camera, optics, illumination) and a separate remote processing unit. This segmentation allows the head-mounted portion to be minimized in size and weight while maintaining tracking accuracy through the distributed architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The decoder and heavy processing electronics are extracted from the head-mounted camera system and placed in a separate remote location. Only the essential imaging components remain on the animal's head, dramatically reducing the weight and complexity of the moving portion while preserving the ability to achieve high measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If a head-mounted camera system is added to track eye movements, then measurement capability is improved, but the system interferes with the animal's natural behavior and vision

Engineering Contradiction:
Improveeye movement detection capabilityVSAvoidinterference with natural behavior and vision
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The illumination system uses infrared light with specific wavelengths that are invisible to rodents, providing local quality differentiation between the illumination spectrum and the rodent's visual spectrum. This allows the camera to capture eye movements without the illumination interfering with the animal's natural vision.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system operates in the infrared spectrum rather than visible light, transitioning to another dimensional space of the electromagnetic spectrum. This allows illumination and imaging without interfering with rodent vision, which is sensitive to different wavelengths than what the infrared camera uses.

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

3Adaptability or versatility

If multiple components are integrated on the head-mounted camera system, then functionality is improved, but the complexity and weight increase

Engineering Contradiction:
Improvesystem functionalityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The decoder and processing electronics are extracted from the head-mounted unit and placed in a separate remote system. This reduces the component count and complexity on the animal's head while maintaining full system functionality through the distributed architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The head-mounted camera unit is designed with multi-functionality, serving both as the primary imaging device and as part of a distributed system that can process multiple data streams. The universal design allows the same basic unit to function in different configurations and experimental setups.

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

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

The system enables precise tracking of eye movements in freely moving rodents, achieving high accuracy in detecting eye rotations and head positions, with minimal disturbance to the animal's natural behavior and vision, and allows for detailed analysis of visual targets.

Implementation Method 1

at least one light emitting element (6) for guiding and emitting light towards the animal's eye

Methodology Applied
Scientific EffectInfrared emission: Infrared Radiation

Implementation Method 2

two light reflectors (7) for reflecting at least partially the light reflected from the animal's eye to the image sensor

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2805671B1Ocular videography system
Publication Date: 2019.03.20 STIFTUNG CAESAR - CENT OF ADVANCED EURO STUDIES & RES ASSOZIIERT MIT DER MAX PLANCK
  • EP2805671B1 patent drawingFigure 1
  • EP2805671B1 patent drawingFigure 2a~2e
  • EP2805671B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to an Ocular Videography System for tracking eye movements of an animal, in particular rats, comprising a camera system suitable of being positioned on the head of an animal to track eye movements of at least one eye of the animal, a head mount on which the camera system is fixed or fixable, wherein, at least one image sensor as well as at least one decoder, for decoding a signal detected by the image sensor, each being comprised by the camera system, and wherein the camera system, and in particular a camera of the camera system, is designed in such a way that it detects a movement of the eye and/or a movement of the head of the animal in a vertical and/or horizontal and/or a torsional direction to an optical axis of the camera system and/or of the optical axis of the animal's eye without interfering with the animal's natural motion dynamics.