Neural Face Shader Volumetric Lightmap Rendering

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Solution Overview

Problem

Current high-fidelity digital human modeling and physically-based rendering techniques require extensive professional intervention and computational resources, resulting in high costs and long production cycles, while neural rendering approaches lack quality and flexibility in relighting and view synthesis.

Innovation Solution

Implementing machine learning models to learn reflectance and indirect lighting representations, generating a volumetric radiance field for rendering images with pore-level details and enabling efficient relighting under various illumination conditions using trained neural networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If professional artists and engineers work hand-in-hand to synthesize complex interactions of light and material with dedicated scanning devices, then photo-realistic quality is achieved, but production costs and production cycles become extremely high

Engineering Contradiction:
Improvephoto-realistic qualityVSAvoidproduction cycle
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical scanning devices and manual light-material synthesis processes with neural network-based computational models. The neural face shader uses learned representations to simulate complex light interactions, substituting the manual mechanical workflow with an automated AI-driven system that maintains photo-realistic quality while dramatically reducing production time

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

Solution Approach 2:

The patent transforms the rendering process by changing from explicit ray-tracing parameter calculations to learned parameter representations through neural networks. The system learns reflectance representations and indirect lighting representations as compact parameter sets that can be efficiently evaluated, converting a computationally intensive process into a faster parameter-based evaluation

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If traditional ray-tracing methods are used for high-fidelity rendering, then rendering quality is improved, but rendering speed decreases

Engineering Contradiction:
Improverendering fidelityVSAvoidrendering speed
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The patent performs preliminary action by pre-training neural networks on extensive light-material interaction data and pre-computing reflectance and lighting representations. These pre-learned models and representations are then reused during actual rendering, eliminating the need for repeated complex ray-tracing calculations while maintaining high rendering fidelity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates simplified copies of complex light transport phenomena through neural network approximations. Instead of performing full ray-tracing simulations, the system uses learned representations that copy the essential characteristics of light-material interactions, providing visually faithful results at much lower computational cost

Inventive Principle:
Principle #26Copying

3Productivity

If neural rendering approaches are used to reduce production costs and time, then productivity is improved, but rendering quality and flexibility in relighting and view synthesis deteriorate

Engineering Contradiction:
Improveproduction efficiencyVSAvoidrendering quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent creates a universal neural face shader system that handles multiple rendering tasks including relighting, view synthesis, and material rendering through a single integrated framework. The learned representations are general-purpose and can be applied to various lighting conditions and camera angles without requiring task-specific models, maintaining both quality and flexibility

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

Solution Approach 2:

The patent introduces volumetric lightmaps as an intermediary representation that bridges the gap between neural network predictions and final rendered images. These lightmaps encode indirect lighting information in a compact form that can be efficiently integrated with direct lighting and material properties, enabling high-quality relighting and view synthesis through the neural framework

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS12002150B2Systems and methods for physically-based neural face shader via volumetric lightmaps
Publication Date: 2024.06.04 UNIV OF SOUTHERN CALIFORNIA
  • US12002150B2 patent drawing
  • US12002150B2 patent drawing
  • US12002150B2 patent drawing

AI summary

Methods and systems are provided for rendering photo-realistic images of a subject or an object using a differentiable neural network for predicting indirect light behavior. In one example, the differentiable neural network outputs a volumetric light map comprising a plurality of spherical harmonic representations. Further, using a reflectance neural network, roughness and scattering coefficients associated with the subject or the object is computed. The volumetric light map, as well as the roughness and scattering coefficients are the utilized for rendering a final image under one or more of a desired lighting condition, desired camera view angle, and/or with a desired visual effect (e.g., expression change).