Glint Mapping via Periodic Illumination Patterns

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Solution Overview

Problem

Correctly mapping glints to their respective light sources is challenging, especially when the object is moving, as it can lead to motion artifacts and requires rapid processing to reduce these issues.

Innovation Solution

The method involves capturing images with different light source patterns, analyzing these images to identify glints, and using per-pixel minimum and maximum operations to map glints to their corresponding light sources, allowing for the generation of a glint-free image that helps in identifying object elements like the pupil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple images are captured to accurately map glints to light sources, then mapping accuracy is improved, but motion artifacts increase and processing time increases

Engineering Contradiction:
Improveglint mapping accuracyVSAvoidmotion artifacts
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system uses periodic illumination patterns where light sources are turned on and off in specific sequences across multiple images. By capturing images with alternating illumination states and processing them to identify glints that appear only when specific lights are on, the system achieves accurate glint-light source mapping while minimizing motion artifacts through the periodic nature of the illumination cycles

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If multiple images are captured to accurately map glints to light sources, then mapping accuracy is improved, but processing complexity increases

Engineering Contradiction:
Improveglint mapping accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the glint detection process by analyzing each image individually with specific illumination patterns, then combining results through logical operations. By dividing the overall mapping task into discrete image capture and processing steps, each handling a specific illumination state, the system achieves accurate mapping while managing processing complexity through modular, stepwise analysis

Inventive Principle:
Principle #1Segmentation

3Object-generated harmful factors

If rapid processing is used to reduce motion artifacts, then motion artifact reduction is improved, but mapping accuracy may deteriorate

Engineering Contradiction:
Improvemotion artifactsVSAvoidglint mapping accuracy
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by capturing multiple images with different illumination patterns before processing. By pre-capturing the necessary image data with controlled lighting conditions, the system establishes a foundation for accurate glint mapping that can be processed efficiently afterward, reducing motion artifacts while maintaining accuracy through the advance preparation of illumination states

Inventive Principle:
Principle #10Preliminary 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 accurate mapping of glints to light sources with minimal images captured, reducing motion artifacts and facilitating the identification of object elements, such as the pupil, even when the object is moving.

Implementation Method 1

A glint is the reflection of a light source off from an object

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3092616B1Mapping glints to light sources
Publication Date: 2019.09.18 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3092616B1 patent drawingFigure 1
  • EP3092616B1 patent drawingFigure 2
  • EP3092616B1 patent drawingFigure 3A

AI summary

The technology disclosed herein provides various embodiments for mapping glints that reflect off from an object to light sources responsible for the glints. Embodiments disclosed herein are able to correctly map glints to light sources by capturing just a few images with a camera. Each image is captured while illuminating the object with a different pattern of light sources. A glint free image may also be determined. A glint free image is one in which the glints have been removed by image processing techniques.