Automated Pupil Tracking for Impairment Detection

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Solution Overview

Problem

Current automated systems fail to accurately and quickly determine impairment in subjects due to limitations in eye gaze tracking and pupillary response analysis, particularly in complex conditions like heavy eye makeup or lighting specularities, leading to subjective and unreliable results.

Innovation Solution

The impairment determination system processes digital image frames to track pupil location, size, and responsiveness, using a combination of contrast enhancement, blink detection, specularity removal, and region-growing algorithms to accurately determine pupil area and location, enabling precise assessment of ocularmotor and pupillary responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If automated systems use traditional pupil detection methods (darkest area thresholding or ellipse fitting), then the system can process images quickly, but the measurement precision deteriorates when light specularities, heavy eye makeup, or bushy eyebrows occlude the pupil

Engineering Contradiction:
Improvepupil location and area measurement accuracyVSAvoidsystem performance under complex conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the pupil detection process into multiple distinct steps: (1) detecting the pupil's approximate location, (2) determining the pupil's boundary by analyzing edge pixels and curvature, and (3) calculating the precise area and centroid. This segmentation allows each step to be optimized independently, with the boundary detection step specifically addressing complex occlusion conditions through curvature analysis rather than simple thresholding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by first detecting the pupil's approximate location and establishing an initial region of interest before conducting the precise boundary detection. This preliminary localization allows the system to focus computational resources on the relevant area and prepare appropriate search parameters for the boundary detection algorithm, improving both speed and accuracy under varying conditions.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If manual measurement methods are used to track pupil responses and eye gaze, then the system can adapt to various conditions, but the productivity and speed of impairment determination deteriorates

Engineering Contradiction:
Improveaccuracy and reliability of impairment determinationVSAvoidspeed of screening large numbers of employees
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system implements self-service through automated image capture and processing. The imaging device automatically captures sequences of eye images, and the processing algorithm automatically detects pupil boundaries, calculates metrics, and determines impairment without requiring manual intervention for each measurement, thereby maintaining high reliability while achieving rapid throughput for screening large numbers of employees.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical measurement processes with an automated digital imaging and image processing system. The algorithm automatically performs pupil detection, boundary tracing, and metric calculation that previously required manual observation and measurement, substituting computational processing for manual mechanical assessment to achieve both speed and reliability.

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

3Measurement precision

If the system processes detailed image sequences to accurately determine pupil area and location, then the measurement precision improves, but the loss of time in processing increases

Engineering Contradiction:
Improveexact area and location of pupilVSAvoidtime to process image frames
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary localization of the pupil's approximate position and establishes initial parameters before conducting the detailed boundary detection. This preliminary action reduces the search space and allows the precise measurement algorithms to operate more efficiently on a focused region, achieving exact pupil area and location determination with reduced processing time compared to analyzing entire eye images.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by focusing computational resources only on the pupil region rather than processing the entire eye image. Once the pupil's approximate location is identified, the system concentrates its processing power on detecting the pupil boundary and calculating metrics within this limited region, achieving precise measurements without the time cost of analyzing the complete eye structure.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS7614745B2System for analyzing eye responses to automatically determine impairment of a subject
Publication Date: 2009.11.10 OCULAR DATA SYSTEMS LLC
  • US7614745B2 patent drawing
  • US7614745B2 patent drawing
  • US7614745B2 patent drawing

AI summary

The impairment determination system automatically determines impairment of a subject based on pupil movement, as well as pupil responses to illumination and target tracking for either eye or both eyes simultaneously. The impairment determination system automatically processes a series of digital image frames, taken during the execution of a predetermined test protocol, to determine pupil location, size, and responsiveness to changes in illumination, which data are used by the impairment determination system to determine impairment of the subject. The present impairment determination system uses a method for quickly and accurately localizing the subject's pupils, as well as their boundaries, area, and center coordinates, which data is used as part of the impairment determination process.