Selective U-Net Influence for Multi-Subject Personalization

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Solution Overview

Problem

Existing diffusion models, such as DreamBooth, struggle with multi-subject personalization tasks, failing to generate high-quality images with proper subject disentanglement and fidelity to text prompts, and often result in identity distortion and mixing.

Innovation Solution

A method and system employing selective U-Net influence, involving fine-tuning a diffusion model with a U-Net state dictionary and ensemble-based image selection, to control and enhance the interpretability of multi-subject personalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If DreamBooth is used for multi-subject personalization, then single-subject personalization efficiency is maintained, but subject disentanglement quality deteriorates

Engineering Contradiction:
Improvepersonalization efficiencyVSAvoidsubject disentanglement quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the U-Net architecture into multiple independent blocks (down blocks, mid blocks, up blocks) that can be selectively influenced during training. Each block processes different aspects of the image generation, allowing the model to learn distinct representations for multiple subjects without mixing their identities. This segmentation enables the model to maintain efficiency while improving subject disentanglement quality.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If standard diffusion model fine-tuning is applied, then training flexibility is improved, but identity preservation deteriorates

Engineering Contradiction:
Improvetraining flexibilityVSAvoididentity preservation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by selectively influencing specific U-Net blocks rather than uniformly fine-tuning the entire model. Different blocks are updated with different learning rates or influence weights, allowing certain regions of the network to preserve identity features while others adapt to new subjects. This localized approach maintains training flexibility while improving identity preservation in the generated images.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If full model fine-tuning is performed, then adaptation capability is improved, but computational complexity increases

Engineering Contradiction:
Improveadaptation capabilityVSAvoidcomputational complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and selectively updates only the necessary U-Net blocks during fine-tuning, rather than updating the entire model. By identifying and modifying only the blocks that need adaptation for multi-subject personalization, the computational complexity is significantly reduced while maintaining adaptation capability. This extraction approach allows efficient training on consumer hardware.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS20260017846A1Method and system for multi-subject personalization with selective u-net influence
Publication Date: 2026.01.15 TATA CONSULTANCY SERVICES LTD
  • US20260017846A1 patent drawing
  • US20260017846A1 patent drawing
  • US20260017846A1 patent drawing

AI summary

Recently, an uptick in the interest in providing interpretability to foundational models has been observed. However, the significant effort is limited to the large language models. Diffusion models have proven significant for the generative AI landscape and the interpretability of these models The present disclosure presents a novel selective U-Net influence (SelUT) technique for greater control and interpretability of DreamBooth for multi-subject personalization task. Specifically, the influence of the trained U-Net block(s) is controlled in the present disclosure during model inference. It provides a greater handle on interpreting the contribution of individual U-Net blocks across quality aspects such as identity disentanglement, image aesthetic, human preference, etc. Furthermore, we present an ensemble selection strategy to incorporate the dynamicity between base DreamBooth and the models trained with selective influence of U-Net block(s) which significantly improve the capability of DreamBooth for multi subject personalization.