GAN Latent Space Segmentation for Style Transfer

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Solution Overview

Problem

Existing methods for processing digital image data, such as generative adversarial networks (GANs), struggle to efficiently generate images with modified styles while preserving the content of the original images.

Innovation Solution

A computer-implemented method using a GAN system that determines a noise prediction and latent variables associated with an extended latent space to generate further digital images with similar content but modified styles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional GAN methods are used to generate images with modified styles, then style diversity is improved, but content preservation deteriorates and artifacts increase

Engineering Contradiction:
Improvestyle diversityVSAvoidcontent preservation accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the latent space into distinct components: a content latent vector (w) that preserves semantic content and a style latent vector (z) that controls stylistic attributes. This segmentation allows independent manipulation of style while preserving content, resolving the contradiction between style diversity and content preservation. The content vector is extracted through an encoder that identifies semantically meaningful representations, while the style vector is sampled from a Gaussian distribution to introduce stylistic variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary encoder network that acts as a bridge between the input image and the latent space representation. This encoder processes the input image to extract the content latent vector, serving as an intermediary that separates content information from style information. The encoder's output serves as the content-preserving foundation that mediates between the original image and the style-modified generated images.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple learning iterations are performed on GAN to improve image generation quality, then generation quality is improved, but computational complexity and training time increase

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

Solution Approach 1:

The patent performs preliminary action by pre-training the encoder to extract meaningful content latent vectors before the main generation process. This preliminary encoding step establishes a robust content representation that can be reused across multiple generation iterations, reducing the need for extensive re-training. The encoder is pre-trained to recognize and preserve semantic content, which then serves as a stable foundation for subsequent style transfer operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by fixing certain components of the GAN system while only training specific parts. The generator's style-related parameters are trained to produce diverse styles, while the content-related parameters (encoder and content latent vector) are kept fixed or updated minimally. This selective parameter training reduces computational complexity compared to training the entire GAN system from scratch, while still achieving high generation quality.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the latent space is extended to allow more style variations, then style flexibility is improved, but generator output stability deteriorates

Engineering Contradiction:
Improvestyle flexibilityVSAvoidgenerator output stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by assigning different properties to different regions of the latent space. The content latent vector (w) is treated with local quality constraints to ensure it preserves semantic content, while the style latent vector (z) is allowed greater freedom to explore stylistic variations. This localized approach to latent space management maintains stability in the content dimension while providing flexibility in the style dimension.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent extends the latent space by adding another dimension - the style latent vector z - while maintaining the original content dimension w. This dimensional extension allows the system to explore style variations in the new z-dimension without disrupting the stability of the content representation in the w-dimension. The orthogonal nature of these dimensions enables independent control of content and style.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4358015B1Method of and apparatus for processing digital image data
Publication Date: 2025.02.19 ROBERT BOSCH GMBH
  • EP4358015B1 patent drawingFigure 1~3
  • EP4358015B1 patent drawingFigure 4~5
  • EP4358015B1 patent drawingFigure 6A~8

AI summary

A method, for example computer-implemented method, of processing digital image data, comprising: determining, by an encoder configured to map a first digital image to an extended latent space associated with a generator of a generative adversarial network, GAN, system, a noise prediction associated with the first digital image, determining, by the generator of the GAN system, at least one further digital image based on the noise prediction associated with the first digital image and a plurality of latent variables associated with the extended latent space.