Make It Up: Fake Images, Real Gains in Generalized Few-shot Semantic Segmentation

TL;DR

Syn4Seg framework enhances GFSS performance by generating diverse synthetic images and pseudo-labels, achieving significant improvements on PASCAL-5i and COCO-20i.

cs.CV 🔴 Advanced 2026-03-28 39 views
Guohuan Xie Xin He Dingying Fan Le Zhang Ming-Ming Cheng Yun Liu
GFSS synthetic data pseudo-labels boundary refinement diffusion models

Key Findings

Methodology

Syn4Seg employs High-quality Diverse Image Generation (HDIG) and Adaptive Pseudo-label Enhancement (APE) to expand novel class coverage and improve pseudo-label quality. HDIG uses category prototypes to guide diffusion models for diverse image generation, APE enhances pseudo-labels through two-stage filtering and relabeling, and SAM-based Boundary Refinement (SABR) improves boundary precision.

Key Results

  • On PASCAL-5i under 5-shot conditions, Syn4Seg improved mIoU by 2.20% and hIoU by 3.28%.
  • On COCO-20i under 5-shot conditions, Syn4Seg improved mIoU by 3.69% and hIoU by 4.34%.
  • Ablation studies confirmed the effectiveness of HDIG, APE, and SABR modules.

Significance

Syn4Seg significantly enhances GFSS performance, providing a scalable solution in data-scarce scenarios. By generating diverse synthetic images and high-quality pseudo-labels, Syn4Seg improves novel class generalization and boundary precision. This research offers new insights for the GFSS field, potentially impacting future research directions and application development.

Technical Contribution

Syn4Seg introduces new mechanisms for high-quality diverse image generation and adaptive pseudo-label enhancement, significantly boosting GFSS performance. Compared to existing methods, Syn4Seg not only expands novel class coverage but also improves pseudo-label precision through boundary refinement, offering new technical pathways for GFSS.

Novelty

Syn4Seg is the first to combine diffusion models and adaptive pseudo-label enhancement for novel class coverage expansion and pseudo-label quality improvement in GFSS. Compared to traditional methods, Syn4Seg excels in enhancing novel class generalization and boundary precision.

Limitations

  • In complex scenarios, generated pseudo-labels may still contain noise, affecting model performance.
  • High computational resource requirements may limit its application in resource-constrained environments.

Future Work

Future work could explore reducing computational resource requirements and improving the speed and quality of pseudo-label generation. Additionally, research could investigate applying Syn4Seg to other domains, such as object detection and instance segmentation.

AI Executive Summary

Generalized Few-shot Semantic Segmentation (GFSS) faces challenges due to the scarcity of novel class samples. Existing methods often rely on limited manual annotations for novel classes, leading to insufficient generalization. The Syn4Seg framework significantly enhances GFSS performance by generating diverse synthetic images and high-quality pseudo-labels.

Syn4Seg first expands novel class coverage through High-quality Diverse Image Generation (HDIG), then improves pseudo-label quality via Adaptive Pseudo-label Enhancement (APE), and finally refines pseudo-label boundary precision using SAM-based Boundary Refinement (SABR). Experimental results show significant performance improvements on PASCAL-5i and COCO-20i datasets.

This research not only provides a scalable solution for GFSS but also potentially influences future research directions and application development. Syn4Seg's success demonstrates the potential of synthetic data in GFSS, offering new insights for addressing data scarcity challenges.

Deep Analysis

Background

Generalized Few-shot Semantic Segmentation (GFSS) aims to address the scarcity of novel class samples. Traditional FSS methods rely on specific support sets, limiting scalability and efficiency. Recent advances in diffusion models offer new possibilities for GFSS by generating diverse synthetic images to alleviate data scarcity.

Core Problem

The core problem of GFSS is achieving efficient segmentation of novel classes with limited annotations. Existing methods often rely on limited manual annotations for novel classes, leading to insufficient generalization. Additionally, the quality of generated pseudo-labels is often low, affecting model performance.

Innovation

Syn4Seg employs High-quality Diverse Image Generation (HDIG) and Adaptive Pseudo-label Enhancement (APE) to expand novel class coverage and improve pseudo-label quality. HDIG uses category prototypes to guide diffusion models for diverse image generation, APE enhances pseudo-labels through two-stage filtering and relabeling, and SAM-based Boundary Refinement (SABR) improves boundary precision.

Methodology

  • �� High-quality Diverse Image Generation (HDIG): Uses category prototypes to guide diffusion models for diverse image generation.
  • �� Adaptive Pseudo-label Enhancement (APE): Enhances pseudo-labels through two-stage filtering and relabeling.
  • �� SAM-based Boundary Refinement (SABR): Uses Segment Anything Model to refine pseudo-label boundaries.

Experiments

Experiments were conducted on PASCAL-5i and COCO-20i datasets to validate Syn4Seg's performance under 1-shot and 5-shot conditions. The experimental design included baseline comparisons, ablation studies, and the impact of different parameter settings.

Results

On PASCAL-5i under 5-shot conditions, Syn4Seg improved mIoU by 2.20% and hIoU by 3.28%. On COCO-20i under 5-shot conditions, Syn4Seg improved mIoU by 3.69% and hIoU by 4.34%. Ablation studies confirmed the effectiveness of HDIG, APE, and SABR modules.

Applications

Syn4Seg can be applied in scenarios requiring high-precision semantic segmentation, such as autonomous driving and medical image analysis. Its high-quality pseudo-labels and diverse synthetic images can significantly enhance model generalization.

Limitations & Outlook

Syn4Seg may still encounter pseudo-label noise in complex scenarios, affecting model performance. Additionally, high computational resource requirements may limit its application in resource-constrained environments. Future work could explore reducing computational resource requirements and improving pseudo-label generation speed and quality.

Plain Language Accessible to non-experts

Imagine you're in a kitchen, and Syn4Seg is like a smart chef that can automatically generate ingredients. Traditional methods require you to manually prepare each ingredient, but Syn4Seg can generate diverse ingredients based on the dish you want to make, ensuring their quality and freshness. This way, you can not only make more types of dishes but also ensure each dish tastes great. This smart chef also optimizes the ingredient generation process based on your feedback, ensuring it provides the best ingredients every time.

ELI14 Explained like you're 14

Hey there! Have you ever thought about having a super-smart artist who can help you draw any picture you want? Syn4Seg is like that artist! It can automatically generate all sorts of pictures based on the prompts you give, and these pictures look super real. Even cooler, it can help you color these pictures to make them look perfect. Imagine just telling it what you want, and it takes care of everything. Isn't that cool?

Glossary

GFSS (Generalized Few-shot Semantic Segmentation)

A technique for segmenting novel classes with limited annotations.

Used to address the scarcity of novel class samples.

HDIG (High-quality Diverse Image Generation)

A technique for generating diverse images using category prototypes to guide diffusion models.

Used to expand novel class coverage.

APE (Adaptive Pseudo-label Enhancement)

A technique for enhancing pseudo-labels through two-stage filtering and relabeling.

Used to improve pseudo-label quality.

SABR (SAM-based Boundary Refinement)

A technique using the Segment Anything Model to refine pseudo-label boundaries.

Used to improve boundary precision of pseudo-labels.

Diffusion Models

A technique for generating diverse images through a diffusion process.

Used for generating diverse synthetic images.

Open Questions Unanswered questions from this research

  • 1 How to efficiently apply Syn4Seg in resource-constrained environments?
  • 2 How to further improve the speed and quality of pseudo-label generation?

Applications

Immediate Applications

Autonomous Driving

Syn4Seg's high-quality pseudo-labels can enhance the semantic segmentation accuracy of autonomous driving systems.

Long-term Vision

Medical Image Analysis

Applying Syn4Seg in medical imaging can improve lesion area identification accuracy, aiding medical diagnosis.

Abstract

Generalized few-shot semantic segmentation (GFSS) is fundamentally limited by the coverage of novel-class appearances under scarce annotations. While diffusion models can synthesize novel-class images at scale, practical gains are often hindered by insufficient coverage and noisy supervision when masks are unavailable or unreliable. We propose Syn4Seg, a generation-enhanced GFSS framework designed to expand novel-class coverage while improving pseudo-label quality. Syn4Seg first maximizes prompt-space coverage by constructing an embedding-deduplicated prompt bank for each novel class, yielding diverse yet class-consistent synthetic images. It then performs support-guided pseudo-label estimation via a two-stage refinement that i) filters low-consistency regions to obtain high-precision seeds and ii) relabels uncertain pixels with image-adaptive prototypes that combine global (support) and local (image) statistics. Finally, we refine only boundary-band and unlabeled pixels using a constrained SAM-based update to improve contour fidelity without overwriting high-confidence interiors. Extensive experiments on PASCAL-$5^i$ and COCO-$20^i$ demonstrate consistent improvements in both 1-shot and 5-shot settings, highlighting synthetic data as a scalable path for GFSS with reliable masks and precise boundaries.

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