Real-time Facial Performance Capture with Adaptive PCA

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Solution Overview

Problem

Existing performance capture techniques require extensive training sessions and generic expressions, which fail to accurately capture the nuances of a subject's facial expressions due to interpolation errors and lack of pre-processed expressions, leading to complex and costly animation processes.

Innovation Solution

The implementation of real-time, calibration-free performance capture using video and depth inputs, where a neutral scan generates a 3D tracking model refined by adaptive principal component analysis (PCA) with on-the-fly shape correctives, allowing for incremental learning and improved expression tracking without additional training sessions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If extensive training sessions are used to capture subject-specific expressions, then the accuracy of expression capture is improved, but the time required and complexity of the process increases

Engineering Contradiction:
Improveexpression capture accuracyVSAvoidtraining session duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by capturing a neutral scan of the subject and generating a customized digital model with blendshapes in advance. This preliminary model serves as a foundation that can be refined over time without requiring extensive retraining, thus reducing the time needed for accurate expression capture while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs dynamic refinement through adaptive PCA models that continuously update and improve the 3D model of the subject over time. This dynamic approach allows the system to learn and adapt to the subject's unique expressions progressively, achieving high accuracy without requiring lengthy initial training sessions.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If generic expressions are used for performance capture, then the ease of operation is improved, but the measurement precision of subject-specific nuances deteriorates

Engineering Contradiction:
Improveease of performance captureVSAvoidsubject-specific expression accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system applies local quality by creating subject-specific blendshapes and correctives that are tailored to the individual subject's unique facial characteristics. This allows the system to maintain ease of operation with automated capture while achieving high precision in capturing subject-specific nuances through personalized local adjustments.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system enables self-service by automatically refining the 3D model using adaptive PCA techniques that learn from the subject's expressions during the capture process itself. This eliminates the need for manual training while preserving subject-specific accuracy, as the system serves itself by continuously improving its own model based on captured data.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If interpolation methods are used to capture expressions not present in training data, then the versatility is improved, but the manufacturing precision of expression accuracy deteriorates

Engineering Contradiction:
Improveexpression variety captureVSAvoidexpression depiction accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system implements feedback through adaptive PCA models that continuously refine their understanding of the subject's expressions based on captured data. This feedback mechanism allows the system to maintain high precision even when capturing expressions not present in initial training data, as the model learns and adapts to new expression patterns in real-time.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses dynamic model refinement where the PCA model continuously updates its parameters based on captured expressions. This dynamic adaptation enables the system to achieve both versatility in capturing varied expressions and high precision in depicting accuracy, as the model evolves to better represent the subject's unique expression patterns.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS9317954B2Real-time performance capture with on-the-fly correctives
Publication Date: 2016.04.19 LUCASFILM ENTERTAINMENT COMPANY LTD
  • US9317954B2 patent drawing
  • US9317954B2 patent drawing
  • US9317954B2 patent drawing

AI summary

Techniques for facial performance capture using an adaptive model are provided herein. For example, a computer-implemented method may include obtaining a three-dimensional scan of a subject and a generating customized digital model including a set of blendshapes using the three-dimensional scan, each of one or more blendshapes of the set of blendshapes representing at least a portion of a characteristic of the subject. The method may further include receiving input data of the subject, the input data including video data and depth data, tracking body deformations of the subject by fitting the input data using one or more of the blendshapes of the set, and fitting a refined linear model onto the input data using one or more adaptive principal component analysis shapes.