ABACUS: A Benchmark for Image Editing Models to Assess Object Category and Counting Under Scene Conservation
Organizations: Universit´e Paris-Saclay, CEA, List, F-91120 Palaiseau, France
Abstract
Instruction-based image editing models can now add, remove a specified number of objects or change their category while preserving the scene. Yet these models often fail to produce the correct number, and these failures grow sharply as scenes become more complex and the requested count increases. Current benchmarks largely miss this problem: they score edits with holistic similarity metrics or with vision-language model (VLM) judges that are themselves poor at counting, so numerical errors go unnoticed or are graded incorrectly. As a result, the true numerical ability of today's editing models has never been accurately measured. We address this issue with ABACUS, a new benchmark, evaluation protocol and dedicated scoring metric for numerical image editing. Our protocol is judge-free: no VLM or MLLM scores an edit or counts objects (a VLM only confirms the category of rare ambiguous crops). Instead, it verifies each edit at the instance level against panoptic ground truth confirmed by detector consensus, checking both that the exact requested count was achieved and that the rest of the scene was preserved, across the add, remove and change operations. By evaluating leading image editors, our method reveals substantial numerical editing failures that worsen with increasing scene complexity and object count; failures that prior benchmarks often overlooked or misjudged.
Figures & tables
| Add | Remove | Change | Overall ( ) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model | E | M | H | E | M | H | E | M | H | CF | SC | OC | Score |
| Gemini 2.5 Flash Image [ 12 ] | 0.52 | 0.39 | 0.26 | 0.45 | 0.30 | 0.18 | 0.31 | 0.22 | 0.12 | 0.59 | 0.77 | 0.64 | 0.29 |
| Seedream 4.0 [ 36 ] | 0.55 | 0.42 | 0.28 | 0.46 | 0.31 | 0.20 | 0.38 | 0.25 | 0.14 | 0.60 | 0.79 | 0.66 | 0.31 |
| GPT-Image-1 [ 27 ] | 0.51 | 0.36 | 0.25 | 0.38 | 0.24 | 0.17 | 0.31 | 0.18 | 0.11 | 0.56 | 0.75 | 0.62 | 0.26 |
| Qwen-Image-Edit [ 40 ] | 0.35 | 0.23 | 0.13 | 0.26 | 0.18 | 0.08 | 0.18 | 0.11 | 0.05 | 0.42 | 0.69 | 0.55 | 0.16 |
| FLUX.1 Kontext [ 4 ] | 0.30 | 0.20 | 0.12 | 0.24 | 0.14 | 0.08 | 0.14 | 0.09 | 0.05 | 0.39 | 0.67 | 0.53 | 0.14 |
| Evaluator | Easy | Medium | Hard | Overall |
|---|---|---|---|---|
| Grounding-DINO [ 23 ] | 0.37 | 0.26 | 0.23 | 0.28 |
| Qwen3.6-27B (thinking) | 0.71 | 0.54 | 0.45 | 0.55 |
| ABACUS (ours) | 0.89 | 0.82 | 0.76 | 0.82 |
| Editor | ABACUS | Solo VLM | Single det. |
|---|---|---|---|
| Seedream 4.0 [ 36 ] | 0.83 | 0.54 | 0.25 |
| Gemini 2.5 [ 12 ] | 0.81 | 0.53 | 0.24 |
| GPT-Image-1 [ 27 ] | 0.81 | 0.51 | 0.23 |
| Qwen-Image-Edit [ 40 ] | 0.80 | 0.47 | 0.22 |
| FLUX.1 Kontext [ 4 ] | 0.80 | 0.43 | 0.20 |
| Step1X-Edit [ 24 ] | 0.80 | 0.41 | 0.18 |
Appendix figures & tables27 assets
Supplementary material from the paper’s appendix.
Appendix
| Op. | Pipeline output | Symbol | Role in the Score |
| Add | new instances; CF (Eq. 4 ) | ||
| originals destroyed; OC (Eq. 5 ) | |||
| Remove | removed instances; CF (Eq. 9 ) | ||
| spurious additions; OC (Eq. 9 ) | |||
| Change | in-place changes; CF (Eq. 10 ) | ||
| deleted, not replaced; OC |
| Add | Remove | Change | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Model | Factor | E | M | H | E | M | H | E | M | H |
| 1,159 | 1,363 | 1,374 | 1,146 | 1,340 | 1,308 | 1,000 | 1,128 | 1,126 | ||
| Seedream 4.0 [ 36 ] | CF | 0.762 | 0.662 | 0.579 | 0.684 | 0.563 | 0.513 | 0.677 | 0.541 | 0.469 |
| SC | 0.922 | 0.852 | 0.776 | 0.901 | 0.800 | 0.724 | 0.839 | 0.726 | 0.607 | |
| OC | 0.782 | 0.745 | 0.633 | 0.745 | 0.686 | 0.530 | 0.677 | 0.624 | 0.476 | |
| 0.5494 | 0.4202 | 0.2844 | 0.4591 | 0.3090 | 0.1968 | 0.3845 | 0.2451 | 0.1355 | ||
| Variant | Acc. vs. human |
|---|---|
| Full ABACUS | 0.82 |
| w/o ambiguity block (VLM verifier) | 0.79 |
| single detector (avg. RF-only, Co-only) | 0.71 |
| w/o inpainting (clean-image isolation) | 0.70 |
| w/o ground-truth completion | 0.69 |
| w/o one-to-one alignment | 0.36 |
| Tier | (count-correct) | ABACUS recall | False-neg. rate |
|---|---|---|---|
| Easy | 200 | 0.97 | 0.03 |
| Medium | 160 | 0.91 | 0.09 |
| Hard | 120 | 0.86 | 0.14 |
| Overall | 480 | 0.92 | 0.08 |
| Factor of the ABACUS Score | Agreement with humans |
|---|---|
| Count fidelity (exact count) | |
| Original-category conservation | (bal. acc. ) |
| In-place change-correspondence | |
| Scene consistency | |
| Combined ABACUS Score | (ordering ) |
| Threshold | Governs | Max agreement |
|---|---|---|
| presence gate (SAM-3) | ||
| containment | ||
| centroid-distance gate | ||
| appearance confirmation | ||
| matcher keep-margin |
| Aggregation | Best real editor | Do-nothing editor |
|---|---|---|
| Arithmetic mean of CF, SC, OC | (nearly ties) | |
| Product (ours) | (rejected) |
| Component | Role | Version / model ID |
|---|---|---|
| Seedream 4.0 | editor | seedream-4-0-250828 (hosted API, queried 2026) |
| Gemini 2.5 Flash Image | editor | gemini-2.5-flash-image-preview |
| GPT-Image-1 | editor | gpt-image-1 |
| Qwen-Image-Edit | editor | Qwen/Qwen-Image-Edit |
| FLUX.1 Kontext | editor | black-forest-labs/FLUX.1-Kontext-dev |
| Step1X-Edit | editor | stepfun-ai/Step1X-Edit |
| Evaluation detector set | Agreement | Ordering |
|---|---|---|
| RF-DETR + Co-DETR (ViT-L), default | — | |
| RF-DETR + DINO (Swin-L) | preserved | |
| RF-DETR + YOLO26-X | preserved | |
| YOLO26-X + DINO (Swin-L) | preserved |
| Agreement | Overall | Hard |
|---|---|---|
| Human vs. human, Krippendorff | ||
| Human vs. human, raw | ||
| ABACUS vs. human, raw | ||
| Gap to the raw human ceiling |
Image Editing Evaluation
Image editing evaluation measures whether edits follow instructions while preserving identity, context, and visual quality.
See all 91 papers