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.

ℒF

Fine-grained characteristic

Be closer to your class.

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

ℒS

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