A DATASET & BENCHMARK FOR DIFFUSION-BASED SUPER-RESOLUTION

DISRQAD
Diffusion Image Super-Resolution
Quality Assessment Dataset and Benchmark

Nikita Kukuzei1,*Artem Borisov1Evgeney Bogatyrev2Khaled Abud2Egor Chistov1Dmitriy Vatolin2

Moscow, Russia · * Corresponding author

THE PERCEPTUAL QUALITY QUESTION

More detail. Better image?

Diffusion SR can create plausible textures
and generate images that surpass the original in perceived visual quality.

Figure 1 From visible artifacts to perceptually improved detail. Scores below SR outputs are human mean opinion scores (MOS). HR references were not scored under the final protocol. Click any figure to explore ↗
14,000human-rated SR outputs
205,578quality judgments
14SR methods · 10 diffusion + 4 classic
62metric configurations · 51 + 11 adapted

01 / OVERVIEW

Human judgment meets generative detail.

Diffusion-based super-resolution can create visually plausible detail that is not supported by the low-resolution input. Do image quality metrics agree with people?

We introduce DISRQAD, a subjective-quality dataset and diagnostic benchmark with mean opinion scores for 14,000 outputs from ten diffusion and four non-diffusion methods, four low-resolution degradation conditions, and ×2 / ×4 upscaling. We evaluate 51 standard full-reference and no-reference configurations and 11 adapted variants.

Agreement with MOS is substantially weaker on diffusion outputs. The strongest standard NR baseline reaches 0.431 SRCC on diffusion SR; the strongest standard NR correlation on non-diffusion SR is 0.813. A pruned and distilled Q-ReAlign-mini student reaches 0.496 on diffusion SR.

What the scores mean. DISRQAD measures perceived output quality. Raters see neither the LR input nor the HR reference; visually attractive but scene-inconsistent details may receive high scores. Fidelity and semantic preservation are separate assessment targets.

01

A broad human-rated dataset

10,000 diffusion and 4,000 classic outputs, selected from a diverse generation pool and scored directly by observers.

02

A diagnostic metric benchmark

Traditional, CNN and vision–language IQA, evaluated separately by SR family, generator, degradation and scale.

03

A case study in adaptation

Fine-tuning analysis and an efficient student illustrate both the potential and the trade-offs of SR-specific training.

Research context: fidelity, appearance and related benchmarks

Super-resolution can introduce oversharpening, ringing, unnatural textures, hallucinated objects and changes to salient regions such as faces. A visually attractive output may differ from the LR evidence and the HR reference. DISRQAD isolates the perceived quality of the output as one assessment target.

Full-reference (FR) metrics compare an output to HR: PSNR and SSIM measure pixel or structural correspondence; LPIPS and DISTS compare features; ERQA emphasizes edges; A-FINE relaxes the perfect-reference assumption. No-reference (NR) metrics see only the output: NIQE uses natural-scene statistics; MUSIQ learns subjective ratings; Q-Align and DEQA use vision–language representations. NeuralSBS learns SR preferences; FGResQ combines scores and restoration rankings. Reduced-reference methods use limited reference information and are not a separate track in this benchmark.

SBS180K records preferences between outputs from the same input. FGRestore and LL-Bench combine pairwise preferences and image-level scores across restoration tasks. The RQI study examines FR / NR disagreement on SR preferences. DISRQAD keeps the task fixed to still-image SR and varies generator family, using direct five-category ratings. Video-SR benchmarks such as VSRQAD and studies of codec-compressed or streaming SR address temporal and video-specific artifacts outside this setting.

SRCC measures ranking agreement; PLCC measures linear agreement. Kendall correlation is another common IQA measure, but the supplied numeric tables here report SRCC and PLCC. Bibliographic references for the methods and related work are available in the full PDF.

02 / THE DATASET

From diverse sources to reliable opinions.

Source selection, controlled degradations, broad SR coverage and direct human ratings.

Dataset construction Two distinct selections: sources before generation, then representative outputs for annotation.
1

468k+ candidates

KonIQ-10K, COCO, AVA and FLIVE. Structural and semantic clustering selects detailed, visually clean sources.

2

10,036 HR sources

Four LR conditions at two scales produce 80,288 inputs. This is the full source pool, before output sampling.

3

1,124,032 outputs

802,880 diffusion + 321,152 non-diffusion outputs. Feature clustering selects 14,000 for human annotation.

4

Direct MOS

More than 80 observers; at least 13 ratings per output on a five-category no-reference quality scale.

DIFFUSION & FLOW PRIORS

10 diffusion SR methods

ResShiftSinSRSeeSRSUPIRPASDPASD-SDXLInvSRCODSRDiT4SRPassionSR

CONVENTIONAL COMPARISON TRACK

4 non-diffusion methods

SwinIRRealSRHATReal-ESRGAN

Four LR conditions: resized, Gaussian blur, additive noise and JPEG compression. Both ×2 and ×4 are evaluated.

How does DISRQAD compare with existing SR datasets?

Earlier datasets emphasize non-diffusion SR. SRIQA-Bench and ISRGen-QA include five diffusion methods each. DISRQAD expands generator coverage within a common direct-rating protocol. Pairwise preferences and absolute scores answer different questions.

SR datasets with per-image scores · Paper Table 1
DatasetSourcesSR outputsNon-diff. methodsDiffusion methodsHuman input
CVIU-2017301,62090Ratings
QADS20980210Pairs
SISRSet1536080Pairs
RealSRQ601,620100Pairs
SISAR*10012,600*10*0Ratings
SRIQA-Bench1001,00055Pairs
ISRGen-QA19720105Ratings
RQI study3122,18443Pairs
DISRQAD10,036†14,000410Ratings

* SISAR directly rates 1,800 outputs; 10,800 scores are inferred. Its method count includes six SR algorithms and four combined operations. † DISRQAD reports the full source pool, not the number of unique sources in the rated subset. SISAR sources are LR inputs; other source counts refer to HR inputs.

03 / THE BENCHMARK

The diffusion assessment gap.

High agreement on classic SR does not guarantee agreement on generated detail.

60/62

metric variants have lower SRCC
on diffusion outputs.

Across the 51 standard configurations, median SRCC drops from 0.65 to 0.27; median PLCC drops from 0.60 to 0.31.

Agreement with human ratings

Non-diffusionDiffusion

SRCC · higher is better · selected baselines and the distilled student. The strongest standard diffusion NR baseline is Q-ReAlign-pro (0.431).

Explore all 62 configurations

Signed correlations with direct MOS. Lower-is-better metrics are sign-reversed; PLCC is computed without nonlinear fitting. The two SR families are evaluated separately.

62 configurations · Paper Tables 3 & 5
MetricTypeNon-diff. SRCCNon-diff. PLCCDiffusion SRCCDiffusion PLCC

FT = fine-tuned on SRIQA-Bench. The distilled student is shown separately from standard baselines. MOS-annotated DISRQAD outputs are evaluation data for these results; these adapted baselines were not trained on their MOS.

04 / DIAGNOSTIC ANALYSIS

A single score hides the difficult cases.

Explore correlations within each generator, degradation and upscaling subset.

Within-subset SRCC · Paper Table 4
SubsetPSNR · FRTOPIQ-FRQ-Align · NRDistilled student · NR

Each coefficient uses only its indicated subset. Colors indicate correlation magnitude, not statistical significance.

Generator matters

PassionSR and ResShift yield the highest within-method SRCC for 36 and 20 of 62 variants. DiT4SR yields the lowest for 38. CODSR and PASD have median SRCCs of 0.135 and 0.158.

Blur is often easier to rank

On diffusion SR, blur yields the highest SRCC for almost all metrics. The distilled student reaches 0.542 on blur, compared with 0.466 on resized inputs.

Scale changes the picture

52 of 62 variants have higher diffusion SRCC at ×4 than ×2. For non-diffusion SR, only 25 variants follow this direction.

05 / DOMAIN ADAPTATION

Fine-tuning helps. Transfer is uneven.

SR-specific supervision can improve diffusion agreement while reducing performance elsewhere.

Ten baselines were fine-tuned on SRIQA-Bench: AHIQ, LPIPS-AlexNet, LPIPS-VGG, PieAPP, TOPIQ-FR, ARNIQA, MUSIQ, LIQE, TOPIQ-NR and Q-ReAlign-mini. Three improved on both SR tracks; other effects depend on the metric and domain.

Simple fine-tuning substantially reduced quality on non-SR distortions in KonIQ-10K, KADID and SPAQ. Specialized training should preserve broader IQA behavior rather than optimize only one track.

See all adapted configurations →

TOPIQ-FR

Diffusion SRCC0.397 → 0.436

Non-diffusion SRCC0.811 → 0.694

MUSIQ

Diffusion SRCC0.273 → 0.308

Non-diffusion SRCC0.605 → 0.497

Baseline fine-tuning settings

Batch size 8, up to 30 epochs, initial learning rate 10⁻⁴, MSE against MOS, Adam optimizer, and checkpoint selection by SRCC using the IQA-PyTorch interface. LIQE uses 5 × 10⁻⁶ for convergence; Q-ReAlign-mini is limited to 2 epochs because of its model size and rapid convergence.

06 / AN EFFICIENT SR-ADAPTED METRIC

Smaller model. Stronger diffusion agreement.

A pruned and hierarchically distilled Q-ReAlign-mini student, followed by SR adaptation.

340Mparameters
1.3 GBpeak VRAM
6.37images / second
0.496diffusion SRCC
Architecture & training Retain the visual encoder, prune the language stack, then combine token-based and continuous quality predictions.
01 / PRUNE

24 → 12 language modules

Remove two Gated DeltaNet modules from each four-module group. Keep the visual encoder and restrict the vocabulary to 30 tokens.

02 / DISTILL

Multi-level supervision

Match visual features, language features, attention, teacher scores and quality-token distributions on general IQA data.

03 / ADAPT

SR with general-IQA replay

990 SRIQA-Bench training images + 248 general-IQA images; 110 SRIQA-Bench images select the checkpoint.

Accuracy / efficiency · Paper Table 6 · accuracy = SRCC / PLCC
ModelParamsVRAMFPSSRIQA-Bench*DiffusionNon-diffusion
Q-ReAlign-mini0.8B2.3 GB3.760.479 / 0.5040.341 / 0.3930.683 / 0.597
Q-ReAlign-lite4.0B10.7 GB2.690.475 / 0.5190.405 / 0.4580.772 / 0.719
Q-ReAlign-pro9.0B19.2 GB2.650.428 / 0.4880.431 / 0.4690.760 / 0.716
Q-Align8.2B16.0 GB5.390.624 / 0.6770.415 / 0.4870.813 / 0.758
Distilled student0.34B1.3 GB6.370.755 / 0.7940.496 / 0.5420.729 / 0.747

NVIDIA RTX A6000 · BF16 · 512 × 512 inputs. * The 110-image SRIQA-Bench split is validation for checkpoint selection, not an independent test set.

09 / READ THE PAPER

Access the full paper

Paper PDF and supplementary material are available here.

First-page preview of the DISRQAD article with title, authors and abstract.

DISRQAD

Diffusion Image Super-Resolution Quality Assessment Dataset and Benchmark

Nikita Kukuzei, Artem Borisov, Evgeney Bogatyrev, Khaled Abud, Egor Chistov, Dmitriy Vatolin.

A page preview and direct PDF link remain available on devices without embedded PDF support.

The arXiv preprint is available at arXiv:2610.09077 ↗.

10 / CITATION & CREDITS

Build on DISRQAD.

BibTeX citation for the arXiv preprint.

@misc{kukuzei_disrqad,
  title = {DISRQAD: Diffusion Image Super-Resolution Quality
           Assessment Dataset and Benchmark},
  author = {Kukuzei, Nikita and Borisov, Artem and
            Bogatyrev, Evgeney and Abud, Khaled and
            Chistov, Egor and Vatolin, Dmitriy},
  journal = {arXiv preprint arXiv:2610.09077},
  year = {2026},
  eprint = {2610.09077},
  url = {https://arxiv.org/abs/2610.09077}
}

Acknowledgments

The research was carried out using the MSU-270 supercomputer of Lomonosov Moscow State University.

Reproducibility & disclosure

Construction, protocol, evaluation and training settings are documented above and in the full paper. The authors disclose AI assistance with translation, language editing, code drafting and revision, and literature identification; they reviewed the material and take responsibility for the results.

10 / PARTICIPATE

Evaluation of IQA metrics for Diffusion SR

We evaluate image quality assessment metrics for the Diffusion SR task.

GOOGLE FORM

DISRQAD metric evaluation

Submit human judgments to compare IQA metrics on diffusion-based super-resolution outputs.

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