Neural Head Avatar Construction from Image
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Solution Overview
Problem
Conventional techniques for animating source portrait images with motion from target images fail to synthesize realistic details due to limited mesh resolution and coarse texture models, and neglect personal characteristics beyond the facial region, leading to unrealistic distortions and identity changes across different views.
Innovation Solution
A neural head avatar construction system that uses three processing branches to produce tri-planes representing coarse 3D geometry, detailed appearance, and expression, applying volumetric rendering to generate photorealistic images of desired identity, expression, and pose, enabling efficient 3D head avatar reconstruction and animation without further optimization during inference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional techniques use limited mesh resolution and coarse texture models, then the processing speed is faster, but the synthesis of realistic details is poor
Solution Approach 1:
The patent transitions from traditional 2D image processing to 3D volumetric representation using tri-planes. This dimensional change enables realistic detail synthesis by capturing depth information and spatial relationships, while the volumetric rendering process efficiently generates high-quality images without requiring excessive computational resources at each processing stage.
Solution Approach 2:
The patent replaces conventional mesh-based geometric modeling with a neural network-based volumetric rendering system. This substitution eliminates the need for complex mesh generation and texture mapping operations, achieving realistic details through learned representations while maintaining processing efficiency through end-to-end differentiable rendering.
2Adaptability or versatility
If conventional techniques focus exclusively on the facial region, then the processing complexity is reduced, but personal characteristics such as hairstyle or glasses are neglected
Solution Approach 1:
The patent creates a universal 3D head avatar representation that simultaneously captures facial geometry, appearance details, and personal characteristics like hairstyle and glasses. The tri-plane volumetric representation serves multiple functions: storing geometric shape, texture information, and semantic attributes, eliminating the need for separate processing pipelines for different head regions.
3Device complexity
If techniques represent motion as a warping field without explicit 3D understanding, then the device complexity is reduced, but warping artifacts and unrealistic distortions occur
Solution Approach 1:
The patent introduces an explicit 3D head avatar as an intermediary representation between the input image and the output animated images. This intermediary contains structured geometric and appearance information that mediates the transformation process, enabling realistic warping and deformation without the artifacts that occur when directly warping 2D images without 3D understanding.
4Manufacturing precision
If conventional techniques require optimization during inference, then the manufacturing precision is improved, but the inference time increases
Solution Approach 1:
The patent performs all necessary optimization and training operations during the offline training phase, creating a pre-optimized neural head avatar model. During inference, the system only requires a single forward pass through the trained network, eliminating the need for time-consuming optimization steps and achieving both high reconstruction quality and fast processing speed.
Data Source
AI summary
Systems and methods are disclosed that animate a source portrait image with motion (i.e., pose and expression) from a target image. In contrast to conventional systems, given an unseen single-view portrait image, an implicit three-dimensional (3D) head avatar is constructed that not only captures photo-realistic details within and beyond the face region, but also is readily available for animation without requiring further optimization during inference. In an embodiment, three processing branches of a system produce three tri-planes representing coarse 3D geometry for the head avatar, detailed appearance of a source image, as well as the expression of a target image. By applying volumetric rendering to a combination of the three tri-planes, an image of the desired identity, expression and pose is generated.