Neural Network Hair Rendering Temporal Stability

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Solution Overview

Problem

Enabling computing devices to perform image processing operations on digital images captured in varying conditions such as changes in scale, noise, lighting, movement, or geometric distortion is computationally intensive and challenging, especially for power and resource-constrained devices, which affects the efficiency and latency of image data processing in augmented reality applications.

Innovation Solution

The implementation of a neural network model that generates temporally consistent predictions for virtual hair in real-time, using conditioning on the previous frame and a loss function to produce smooth and stable hairstyle changes, reducing high-frequency texture jitter and improving rendering quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If image processing operations are performed on digital images captured in varying conditions, then image processing quality is improved, but computational complexity and processing time increase

Engineering Contradiction:
Improveimage processing qualityVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical image processing methods with a neural network-based system. The neural network model automatically learns and applies appropriate processing operations for different image conditions (scale changes, noise, lighting, movement, geometric distortion) without requiring explicit programming of each processing step, thereby reducing computational complexity while maintaining processing quality.

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

Solution Approach 2:

The system dynamically adjusts processing parameters based on the specific conditions of each image. The neural network analyzes image characteristics and automatically modifies processing parameters to optimize quality for varying conditions such as noise levels, lighting variations, and geometric distortions, reducing the need for complex manual parameter tuning.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If real-time virtual hair generation is implemented, then rendering quality is improved, but power consumption and processing latency increase

Engineering Contradiction:
Improverendering qualityVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The neural network model is pre-trained on extensive datasets of hair images and transformations before deployment. This preliminary training phase allows the model to learn complex hair rendering patterns in advance, enabling it to generate high-quality virtual hair in real-time with reduced computational power during actual operation, thereby lowering power consumption while maintaining rendering quality.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If temporal consistency is achieved through previous frame conditioning, then rendering stability is improved, but processing latency increases

Engineering Contradiction:
Improverendering stabilityVSAvoidprocessing latency
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system uses the previous frame's processed output as a conditional input for generating the current frame. By copying and leveraging information from the previously rendered frame, the neural network maintains temporal consistency and reduces high-frequency texture jitter without requiring complete re-processing of all image elements, thereby achieving rendering stability with minimal additional latency.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20250022264A1Photo-realistic temporally stable hairstyle change in real-time
Publication Date: 2025.01.16 SNAP INC
  • US20250022264A1 patent drawing
  • US20250022264A1 patent drawing
  • US20250022264A1 patent drawing

AI summary

The subject technology trains a neural network based on a training process. The subject technology selects a frame from an input video, the selected frame comprising image data including a representation of a face and hair, the representation of the hair being masked. The subject technology determines a previous predicted frame. The subject technology concatenates the selected frame and the previous predicted frame to generate a concatenated frame, the concatenated frame being provided to the neural network. The subject technology generates, using the neural network, a set of outputs including an output tensor, warping field, and a soft mask. The subject technology performs, using a warping field, a warp of the selected frame and the output tensor. The subject technology generates a prediction corresponding to a corrected texture rendering of the selected frame.