WACV 2026

Reverse Personalization

Attribute-controllable face anonymization
via conditional diffusion inversion.

1University of Trento  2University of Oulu

Input
LDFA
RiDDLE
Textual Inv.
Ours
Subject 1 input face
Subject 1 anonymized by LDFA
Subject 1 anonymized by RiDDLE
Subject 1 anonymized by Textual Inversion
Subject 1 anonymized by our method
Subject 1 our method with aging attribute
Subject 1 our method with Asian ethnicity attribute
Subject 2 input face
Subject 2 anonymized by LDFA
Subject 2 anonymized by RiDDLE
Subject 2 anonymized by Textual Inversion
Subject 2 anonymized by our method
Subject 2 our method with grandma (gender+age) attribute
Subject 2 our method with young Asian attribute
Identity anonymized
✓ Yes
✓ Yes
✓ Yes
✓ Yes
Subject agnostic
✓ Yes
✓ Yes
✗ No
✓ Yes
Attribute & scene preserved
✗ Poor
✗ Poor
✓ Good
✓ Good
Attribute controllable
✗ No
✗ No
✗ No
✓ Yes (Default)
✓ Yes (Aging)
✓ Yes (Ethnicity)

Our method anonymizes faces while enabling attribute-controllable generation — altering age, gender, and ethnicity via simple text prompt substitution, while preserving non-identity attributes and overall image quality.

Abstract

Recent text-to-image diffusion models have demonstrated remarkable generation of realistic facial images conditioned on textual prompts and human identities. However, existing prompt-based methods for removing identity-specific features rely on the subject being well-represented in the pre-trained model or require model fine-tuning.

This work analyzes the identity generation process and introduces a reverse personalization framework for face anonymization. It leverages conditional diffusion inversion, allowing direct image manipulation without text prompts. An identity-guided conditioning branch (IP-Adapter) generalizes beyond the model's training data.

The method supports attribute-controllable anonymization and achieves state-of-the-art balance between identity removal, attribute preservation, and image quality — the first diffusion-based anonymization approach capable of controlling age, gender, and ethnicity during anonymization.

Motivation

Null-text Inversion can change identity only for subjects the model already knows, such as public figures like Obama (top row). Textual Inversion extends this capability to unknown subjects but requires fine-tuning (bottom row). Our method handles both cases without prior model knowledge or fine-tuning.

Input
Null-text Inv.
Textual Inv.
Ours
In model
knowledge
Obama — input
Obama — Null-text Inversion
Obama — Textual Inversion
Obama — Ours
Outside model
knowledge
Private subject — input
Private subject — Null-text Inversion
Private subject — Textual Inversion
Private subject — Ours
No prior knowledge required
✗ No
✓ Yes
✓ Yes
No fine-tuning needed
✗ No
✗ No
✓ Yes

Method

We introduce reverse personalization: applying a negative classifier-free guidance scale to steer generation away from identity-defining features, guided by a conditional inversion via IP-Adapter.

Diagram of conventional prompt-based reweighting approach
Conventional Approach
Diagram of our reverse personalization framework
Our Reverse Personalization

Effect of Guidance Scale

A negative CFG scale drives generation away from the reference identity, increasing anonymization strength. Positive scale reinforces identity (standard behavior).

CFG scale = −8
cfg = −8
CFG scale = −4
cfg = −4
Input — CFG = 0
Input
CFG scale = +4
cfg = +4
CFG scale = +8
cfg = +8
0.773
0.607
ID Distance
0.170
0.229
Increase
Increase

Comparison with Baselines

Qualitative comparison against state-of-the-art face anonymization methods.

CelebA-HQ
Input
Ours
NullFace
FAMS
FALCO
LDFA
DP2
CelebA-HQ subject 04087 — all methods comparison CelebA-HQ subject 04316 — all methods comparison CelebA-HQ subject 04552 — all methods comparison CelebA-HQ subject 14172 — all methods comparison
FFHQ
Input
Ours
NullFace
FAMS
RiDDLE
LDFA
DP2
FFHQ subject 02304 — all methods comparison FFHQ subject 27921 — all methods comparison FFHQ subject 34015 — all methods comparison FFHQ subject 56915 — all methods comparison

Attribute-Controllable Anonymization

By substituting a simple text prompt during reverse personalization, the user can control age, gender, and ethnicity of the anonymized output — a first in diffusion-based face anonymization.

Input
Keep/Change age
Age attribute control — subject 46881
Age attribute control — subject 61462
Input
Keep/Change sex
Sex attribute control — subject 01895
Sex attribute control — subject 61804
Input
Keep/Change race
Race attribute control — subject 11719
Race attribute control — subject 51607

Ablation Study

Component analysis demonstrating the contribution of each element of our reverse personalization framework. Each strip shows (left to right): Input, Ours, DDIM, InstantID.

CelebA-HQ ablation subject 06680 CelebA-HQ ablation subject 12392
FFHQ ablation subject 54355 FFHQ ablation subject 54580

BibTeX

@InProceedings{Kung_2026_WACV,
    author    = {Kung, Han-Wei and Varanka, Tuomas and Sebe, Nicu},
    title     = {Reverse Personalization},
    booktitle = {Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV)},
    month     = {March},
    year      = {2026},
    pages     = {988-999}
}