Structured Light Projection for Accurate Facial Feature Detection

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Solution Overview

Problem

Acquiring training data for machine learning models to detect facial features in HMD wearers is cumbersome and inaccurate due to the time-consuming and expensive process of manual annotation, and after-the-fact image analysis is inadequate in identifying reference points.

Innovation Solution

A method that recursively captures images of an object illuminated by projected structured light, identifies reference points, and modifies the structured light based on these points in each iteration to improve detection in subsequent images, allowing for more accurate identification of facial features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual annotation is used to acquire training data for machine learning models, then the accuracy of reference point identification can be improved, but the time consumption and cost increase significantly

Engineering Contradiction:
Improvereference point identification accuracyVSAvoidtime consumption for data acquisition
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system uses automated algorithms to identify reference points in facial images without requiring manual annotation. The machine learning model automatically detects and marks facial landmarks, enabling the system to acquire training data independently and efficiently, thus resolving the contradiction between accuracy and time consumption.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical process of manual annotation with an automated computational system. Instead of human operators manually marking reference points, the system uses computer vision algorithms and machine learning models to automatically identify and annotate facial features, significantly reducing time consumption while maintaining or improving accuracy.

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

2Extent of automation

If after-the-fact image analysis is used to identify reference points, then the process can be automated, but the accuracy of identifying reference points becomes inadequate

Engineering Contradiction:
Improveautomation of reference point identificationVSAvoidreference point identification accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The system performs preliminary processing of facial images by projecting structured light patterns onto the face before capture. This preprocessing step enhances the visibility and detectability of facial features, enabling the subsequent automated analysis to achieve higher accuracy. The structured light illumination prepares the image data in advance, making reference points more easily identifiable by the automated algorithm.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent modifies the illumination parameters by using structured light patterns instead of conventional lighting. This change in lighting parameters enhances the contrast and definition of facial features in the captured images, thereby improving the accuracy of automated reference point identification while maintaining full automation of the process.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If structured light is projected onto the object to illuminate facial features, then the detection accuracy of facial features can be improved, but the complexity of the system increases

Engineering Contradiction:
Improvefacial feature detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system integrates the structured light projection device with the existing HMD and camera system, making the illumination component serve multiple functions. The same device that captures images also projects structured light patterns, eliminating the need for separate complex illumination systems and reducing overall system complexity while maintaining improved detection accuracy.

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

Data Source

PatentUS11676357B2Modification of projected structured light based on identified points within captured image
Publication Date: 2023.06.13 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • US11676357B2 patent drawing
  • US11676357B2 patent drawing
  • US11676357B2 patent drawing

AI summary

Structured light is projected onto an object, and an image of the object as illuminated by the projected structured light is captured. Reference object points are identified within the captured image, and the structured light projected onto the object is modified based on the identified reference object points. An additional image of the object as illuminated by the modified projected structured light is captured, and additional reference object points are identified within the captured additional image.