Accepted at ECCV 2026
Fine-grained recognition · Dataset distillation

Distill the details
that make a difference.

FD2 preserves subtle, localized cues while building a compact synthetic dataset—turning fine-grained variation from a distillation obstacle into a learning signal.

FrameworkDecoupled DD
FocusLocalized cues
VenueECCV 2026

Hongxu Ma1,†· Guang Li2,†,*· Shijie Wang3· Dongzhan Zhou4· Baoli Sun5· Takahiro Ogawa2· Miki Haseyama2· Zhihui Wang5

1 Zhejiang University 2 Hokkaido University 3 The University of Queensland 4 Shanghai AI Laboratory 5 Dalian University of Technology
Equal contribution * Correspondence to Guang Li (guang@lmd.ist.hokudai.ac.jp)
01 / Motivation

Fine-grained data asks a harder question.

Conventional decoupled distillation is guided by coarse class labels. On fine-grained datasets, that can blur the tiny distinctions between classes—and make distilled images within a class too alike.

A bird is not just a bird. The answer may live in the wing, the beak, or a patch of color.

Conventional DDCoarse

Same-class collapse

Samples inherit nearly identical optimization signals, limiting local diversity.

FD2Fine-grained

Discriminative diversity

Class prototypes guide identity while attention constraints preserve distinct cues.

02 / Framework

One framework.
Three deliberate stages.

FD2 slots into the established decoupled dataset-distillation pipeline without rewriting the recipe.

01

Model pretraining

Counterfactual attention learning discovers discriminative regions and aggregates their representations into class prototypes.

Build prototypes
03

Soft-label generation

The pretrained fine-grained model converts distilled samples into informative soft labels for efficient downstream training.

Transfer knowledge
Framework overview Figure 2
FD2 augments a decoupled distillation pipeline with counterfactual attention learning (CAL), fine-grained characteristic alignment, and same-class attention diversity.
03 / Design

Identity,
without imitation.

Two complementary objectives keep the synthetic set faithful to its class and meaningfully varied within it.

F

Fine-grained characteristic

Be closer to your class.

Align each representation with its class prototype while repelling prototypes from other classes.

S

Attention similarity

Look somewhere different.

Reduce overlap between current and previous attention maps from the same class.

04 / Takeaway

The result

A compact dataset that remembers where to look.

Across fine-grained and general datasets, FD2 integrates seamlessly with decoupled dataset distillation and improves performance in most settings—showing strong transferability.

Fine-grained awarePlug-and-playTransferable
05 / Citation

Build on the details.

If FD2 supports your research, please cite our paper.

@inproceedings{ma2026fd2,
  title   = {FD$^2$: A Dedicated Framework for
             Fine-Grained Dataset Distillation},
  author  = {Ma, Hongxu and Li, Guang and Wang, Shijie
             and Zhou, Dongzhan and Sun, Baoli and
             Ogawa, Takahiro and Haseyama, Miki and
             Wang, Zhihui},
  booktitle = {European Conference on Computer Vision (ECCV)},
  year    = {2026}
}
Full-size FD squared framework diagram