Two-Layer GMM Face Detection via Pose Estimation

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Solution Overview

Problem

Current face detection techniques are limited by their inability to handle multiple poses effectively, require manual labeling of local features, and need separate pattern learning for each pose, making them inefficient for complex pattern recognition and varying conditions.

Innovation Solution

A two-layer Gaussian Mixture Model (GMM) is trained using both spatial and gray-scale distributions of local features, allowing face detection without manual labeling and enabling recognition across various poses by setting global parameters, which defines facial features in a multi-dimensional space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If neural network systems are used for face detection, then detection accuracy is improved, but the system only works well for frontal face poses and does not effectively handle faces with multiple poses

Engineering Contradiction:
Improvedetection accuracyVSAvoidpose handling capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The face detection process is segmented into two independent stages: pose estimation using HMM and face detection using neural networks. This segmentation allows each component to specialize - HMM handles pose variations while NN handles accurate face detection, resolving the contradiction between accuracy and pose adaptability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adapts by first estimating pose and then adjusting detection parameters based on the estimated pose. This dynamic adjustment allows the neural network to maintain high accuracy across different poses rather than being limited to frontal views

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If HMM technique is used for side-view face pose detection, then pose detection capability is improved, but the state distribution and transition probabilities are defined independently which limits control over complex patterns

Engineering Contradiction:
Improvepose detection capabilityVSAvoidmodel control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The HMM model is segmented into independent state distribution parameters and transition probability parameters. This segmentation allows flexible control where state distributions can be adjusted for different facial features while transition probabilities handle the temporal relationships, enabling complex pattern control without excessive complexity

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If manual labeling of salient facial features is performed, then feature recognition accuracy is improved, but the process requires significant manual effort and does not provide optimized segmentation

Engineering Contradiction:
Improvefeature recognition accuracyVSAvoidlabeling effort
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system uses unsupervised learning where the model automatically learns and segments facial features without manual labeling. The HMM naturally identifies feature boundaries and centers through probabilistic modeling, providing optimized segmentation without human intervention while maintaining recognition accuracy

Inventive Principle:
Principle #25Self-service

4Measurement precision

If separate pattern learning is performed for each pose, then detection accuracy for specific poses is improved, but knowledge learned from different poses cannot be shared making the process inefficient

Engineering Contradiction:
Improvepose-specific detection accuracyVSAvoidtraining efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The HMM framework serves as a universal model that learns common patterns across different poses. By modeling the probabilistic relationships of facial features that are consistent across poses, the system enables knowledge sharing while still maintaining pose-specific detection capabilities through the pose estimation stage

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

Data Source

PatentUS7697752B2Method and apparatus for performing object detection
Publication Date: 2010.04.13 GOOGLE TECHNOLOGY HOLDINGS LLC
  • US7697752B2 patent drawing
  • US7697752B2 patent drawing
  • US7697752B2 patent drawing

AI summary

An object detection algorithm that generates a two-layer Gaussian Mixture Model (GMM) during a training session, and subsequent to the training session, uses the two-layer GMM to perform face detection. No labeling of local features is needed. The only input that is provided by a user is the setting of a few global parameters for the image being captured during the training session, such as, for example, the person's facial pose.