Pupillometer Pulse Sequence for Physical Condition Assessment

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Solution Overview

Problem

Conventional pupillometers provide only a limited amount of information from pupil diameter curves, leading to imprecise deductions about a person's physical condition, such as tiredness or blood alcohol content.

Innovation Solution

A pupillometer system that uses a pulse sequence of light pulses with varying colors and intervals, allowing the pupil diameter curve to capture multiple local minima and maxima, and includes a method to determine pupil diameter profiles during both contraction and dilation phases, enhancing the curve's complexity and personalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single light pulse is used to measure pupil diameter, then the measurement process is simple, but the amount of information obtained about physical condition is limited and imprecise

Engineering Contradiction:
Improveprecision of physical condition assessmentVSAvoidcomplexity of light pulse sequence
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies periodic action by using a sequence of light pulses with specific time intervals instead of a single pulse. The pulse sequence includes multiple pulses at different time points (e.g., t1, t2, t3, t4) to capture the dynamic pupillary response over time, generating a pupil diameter profile that contains rich information about physical condition while maintaining a systematic measurement approach.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent employs parameter changes by varying the temporal characteristics of light pulses (intervals between pulses) and using different wavelengths (colors) of light. This allows the system to elicit different phases of pupillary reflex (contraction and dilation) and capture multiple local minima and maxima in the pupil diameter curve, thereby extracting more information about the person's physical state without requiring complex additional hardware.

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If multiple light pulses with different colors and intervals are used, then the pupil diameter profile becomes highly personalized and informative, but the device and measurement process become more complex

Engineering Contradiction:
Improveinformation completeness about physical conditionVSAvoidcomplexity of pulse sequence control
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a multi-functional light source that can emit multiple wavelengths (colors) of light and control various pulse intervals. This single light source performs multiple functions: eliciting pupillary contraction, capturing dilation phase, and generating a comprehensive pupil diameter profile. The evaluation unit also serves multiple purposes by analyzing different features of the pulse response to determine various physical parameters simultaneously.

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

Solution Approach 2:

The system uses feedback by measuring the pupil diameter response to each light pulse and using this information to characterize the complete pupillary reflex pattern. The evaluation unit analyzes the feedback signal (pupil diameter changes over time) to extract information about physical condition, creating a closed-loop measurement process where the response informs the assessment without requiring additional complex intervention.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If short time intervals between pulses are used to prevent pupil recovery, then the pupil diameter profile captures more dynamic information, but the time required for complete measurement may be extended

Engineering Contradiction:
Improveprecision of pupil diameter profilingVSAvoidmeasurement duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by using a limited number of light pulses (e.g., 4 pulses) with specific intervals that are sufficient to capture the essential features of the pupillary reflex without requiring an excessive number of pulses. This provides the right balance between obtaining comprehensive information and maintaining reasonable measurement duration, avoiding both insufficient sampling and unnecessary prolongation.

Inventive Principle:
Principle #16Partial or excessive action

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

This approach enables more accurate assessment of a person's physical condition by providing a highly personalized pupil diameter curve, allowing for precise identification of health status, including blood alcohol content and potential neuronal diseases, and ensuring secure access to workplaces.

Implementation Method 1

A pupillary reflex in humans causes the pupil to shrink when exposed to higher levels of visible light. This reduces the amount of light passing through the pupil onto the retina. Conversely, when exposed to lower levels of visible light, the pupillary reflex causes the pupil to enlarge, allowing a greater amount of light to reach the retina.

Methodology Applied
Scientific EffectPupillary reflex:

Implementation Method 2

a camera configured to record an image sequence with images of a person's eye showing a pupil with the pupillary reflex

Methodology Applied
Scientific EffectPhotography: Photography

Data Source

PatentEP3755203B1Pupillometer and method for operating the pupillometer
Publication Date: 2024.01.10 STELLAR DATA BROADCAST SERVICES GMBH
  • EP3755203B1 patent drawingFigure 1~2
  • EP3755203B1 patent drawingFigure 3~4
  • EP3755203B1 patent drawingFigure 5

AI summary

The invention relates to a pupillometer comprising a light source configured to illuminate a human with a pulse sequence such that a pupillary reflex is caused in the human, a camera configured to record an image sequence with images of an eye of the human exhibiting a pupil with the pupillary reflex, and a signal evaluation unit configured to determine a pupil diameter in the images and a pupil diameter curve (12, 13) therefrom, wherein the pulse sequence has a plurality of temporally successive light pulses (1 to 11) and time intervals (Δ1 to Δ10) between two adjacent light pulses are so short that the pupil diameter does not recover to an initial pupil diameter (16) during the pulse sequence, said initial pupil diameter being present at the time of the first light pulse (1) of the pulse sequence, and in which at least two of the light pulses have a different color.