CVPR 2026

Erasing Thousands of Concepts

Towards Scalable and Practical Concept Erasure for Text-to-Image Diffusion Models

Hoigi Seo* Byung Hyun Lee* Jaehyun Cho Sungjin Lim Se Young Chun
Seoul National University
*Equal contribution. Corresponding author.
Qualitative comparison showing ETC erasing target concepts while preserving remaining concepts in Stable Diffusion v1.4.
Large-scale concept erasure across celebrities, characters, and artistic styles.

Abstract

Large-scale text-to-image diffusion models deliver remarkable visual fidelity but pose safety risks due to their capacity to reproduce undesirable content, such as copyrighted ones. Concept erasure has emerged as a mitigation strategy, yet existing approaches struggle to balance scalability, precision, and robustness, which restricts their applicability to erasing only a few hundred concepts.

We present Erasing Thousands of Concepts (ETC), a scalable framework capable of erasing thousands of concepts while preserving generation quality. ETC models low-rank concept distributions with a Student's t-distribution Mixture Model, performs pin-point target mapping via affine optimal transport, and trains a Mixture-of-Experts module, MoEraser, with a noise injection-restore strategy for robustness to module removal.

2,000+ concepts erased
3 heterogeneous domains
SD v1.4 large-scale validation
SD v3.5-L advanced model extension

Method

ETC turns concept erasure into distribution modeling, transport-based mapping, and scalable MoE training.

Concept distribution modeling and mapping with tMM and affine optimal transport.
Concept embeddings are modeled as tMM distributions. Boundary samples act as anchors, and target concepts are mapped via affine optimal transport.

Concept Distribution Modeling

ETC captures contextual variation by fitting Student's t-distribution mixtures to low-rank text embedding distributions.

Affine Optimal Transport

Target concept distributions are transported toward merged mapping concepts, producing anonymous replacement embeddings while avoiding curated anchor concepts.

MoEraser with NIR

A Mixture-of-Experts erasing module transforms target embeddings, preserves anchors, and restores structured-noise-corrupted projectors to resist module removal.

MoEraser architecture and noise injection-restore training scheme.
MoEraser scales across heterogeneous domains using GLU experts and a router, then uses noise injection-restore tuning to make the erasing module non-removable in practice.

Qualitative Results

ETC removes target concepts while keeping non-target concepts close to the original generation.

Qualitative results for erasing 2072 concepts from Stable Diffusion v1.4.
Erasing 2,072 concepts from SD v1.4 across celebrities, characters, and artistic styles.
Qualitative results for erasing 515 concepts from Stable Diffusion v3.5-L.
Extension to SD v3.5-L with 515 erased concepts, showing the same erasure-preservation behavior on a stronger base model.

Analysis

Key design choices behind ETC's scalability and robustness.

Comparison between tMM and GMM sampling for concept distributions.

Heavy-Tailed Concept Modeling

tMM attenuates concept presence more naturally in low-probability regions than GMM, matching the paper's boundary-based anchor construction.

Affine optimal transport mapping compared with ordinary optimal transport.

Safer Mapping Space

AOT maps a target distribution toward a merged concept triplet, producing novel visual features instead of copying a single replacement identity.

Noise injection-restore rationale for making MoEraser non-removable.

Removal Robustness

NIR corrupts the text-embedding projector and trains MoEraser to restore usable embeddings, so removing the module degrades image generation.

Paper

BibTeX

@inproceedings{seo2026erasing,
  title={Erasing Thousands of Concepts: Towards Scalable and Practical Concept Erasure for Text-to-Image Diffusion Models},
  author={Seo, Hoigi and Lee, Byung Hyun and Cho, Jaehyun and Lim, Sungjin and Chun, Se Young},
  booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},
  year={2026},
  url={https://arxiv.org/abs/2604.16481}
}