One Evaluation Is Enough: Inversion-Free Image Editing with Trajectory Correction
Organizations: State Key Lab of CAD&CG, Zhejiang University · Ant Group · Chongqing Key Laboratory of Image Cognition, Chongqing University of Posts and Telecommunications
Abstract
Real-image editing commonly relies on inversion and iterative sampling, while efficient one-step editors often stabilize a large update by estimating and averaging editing fields at multiple noise levels. We ask a stricter question: is a single temporal field evaluation sufficient for reliable inversion-free editing? Our answer rests on a previously underused duality in a variance-preserving (VP) one-step model: one source-target query at a shared noisy state simultaneously determines a local angular semantic tangent and a clean endpoint displacement. We integrate the tangent over the analytically known remaining VP angle to obtain a nominal one-step transport, and use the endpoint displacement to correct its long-horizon extrapolation through a constrained projection. This transport-first, correction-second construction yields Endpoint-Calibrated Transport (ECT), a closed-form, training-free editor requiring only one noise level, two text conditions packed into one denoiser batch, and one latent update. ECT requires no image inversion, trajectory integration, second temporal observation, or iterative optimization, and can be directly applied to pretrained epsilon-prediction VP one-step generators. Across the reported benchmark settings, ECT delivers stable gains in editing quality within an extremely short editing time.
Figures & tables
| Model | Setting | Time (s) | CPU (%) | Mem. (MiB) | CP | VQ | PC |
|---|---|---|---|---|---|---|---|
| SB-v2 | ChordEdit | 0.265 | 357 | 1298.74 | 3.91 | 4.37 | 4.05 |
| SB-v2 | ECT (2-step) | 0.259 | 446 | 1382.99 | 3.99 | 4.42 | 4.10 |
| SB-v2 | ECT (1-step) | 0.213 -0.5pt | 190 -0.5pt | 1075.93 -0.5pt | 4.03 | 4.45 | 4.13 |
| SD-T | ChordEdit | 0.265 | 357 | 1297.07 | 3.95 | 4.37 | 4.00 |
| SD-T | ECT (2-step) | 0.259 | 452 | 1386.67 | 4.04 | 4.44 | 4.07 |
| SD-T | ECT (1-step) | 0.212 -0.5pt | 190 -0.5pt | 1075.96 -0.5pt | 4.09 | 4.65 | 4.31 |
Appendix figures & tables9 assets
Supplementary material from the paper’s appendix.
Appendix
| Metric | Direction | Input | Primary interpretation |
|---|---|---|---|
| MSE | Masked source/output | Mean pixel error | |
| PSNR | Masked source/output | Log pixel fidelity | |
| SSIM | Masked source/output | Local structure preservation | |
| LPIPS | Masked source/output | Learned perceptual distance | |
| CLIP | Full output/instruction | Target semantic alignment |
| Column | Statistic | Scope | Unit |
|---|---|---|---|
| Time | Arithmetic mean of | Pipeline call | s/image |
| CPU | Time-weighted process utilization | Inference windows | core-% |
| Mem. | Time-weighted process RSS | Inference windows | MiB |
| VRAM | Peak PyTorch reserved memory | Measured run | MiB |
| Score 1: poor | Score 3: adequate | Score 5: excellent |
|---|---|---|
| CP: Content and Identity Preservation | ||
| Severe unintended loss, deformation, or identity/layout change. | Source remains recognizable, with visible unintended local changes. | Unrequested identity, geometry, layout, and detail are preserved. |
| VQ: Visual Quality and Artifact Control | ||
| Severe blur, noise, corruption, or deformation. | Usable output with visible local blur, noise, or edge artifacts. | Sharp, detailed output without visible editing artifacts. |
| PC: Physical and Perceptual Coherence | ||
| Severe conflicts in lighting, perspective, anatomy, scale, depth, material, or style. | Broadly plausible, with minor physical or perceptual inconsistency. | Edited content is naturally integrated and internally coherent. |
| Dimension | Rating criterion |
|---|---|
| Text alignment | Agreement between the edited image and instruction |
| Structure preservation | Preservation of non-target content, identity, geometry, and layout |
| Overall aesthetics | Naturalness, detail, consistency, and artifact control |
| Consistency (background preservation) | |||||
| Seed | PSNR | MSE | LPIPS | SSIM | CLIP |
| 1 | 23.428 | 6.641 | 112.832 | 77.825 | 30.23 |
| 20 | 23.598 | 6.435 | 110.950 | 77.834 | 30.43 |
| 64 | 23.550 | 6.447 | 111.065 | 77.816 | 30.28 |
| 100 | 23.617 | 6.452 | 111.691 | 77.775 | 30.34 |
| 512 | 23.548 | 6.513 | 112.784 | 77.888 | 30.42 |
| VP schedule | ImgEdit-Judge | ||||||
|---|---|---|---|---|---|---|---|
| Setting | CP | VQ | PC | ||||
| 0.945634 | 0.325234 | 1.019 | 0.319 | 2.92 | 4.33 | 3.99 | |
| 0.768440 | 0.639921 | 1.085 | 0.385 | 4.04 | 4.50 | 4.18 | |
| 0.525673 | 0.850686 | 1.196 | 0.496 | 3.48 | 4.35 | 3.96 | |
| 0.288320 | 0.957534 | 1.335 | 0.635 | 3.30 | 4.15 | 3.59 | |
| Ref. : ChordEdit (SD-T) | — | — | — | — | 3.95 | 4.37 | 4.00 |
| Consistency (background preservation) | |||||
|---|---|---|---|---|---|
| Setting | PSNR | MSE | LPIPS | SSIM | CLIP |
| (ours) | 23.740 | 6.220 | 109.040 | 78.100 | 30.20 |
| 21.050 | 11.655 | 146.676 | 74.432 | 30.70 | |
| 19.084 | 18.150 | 183.486 | 71.209 | 30.60 | |
| 17.724 | 24.364 | 213.623 | 68.508 | 30.20 | |
| 16.717 | 30.136 | 239.572 | 66.179 | 29.90 | |
Diffusion-Based Image Editing
Diffusion-based image editing changes image content, style, or attributes while aiming to preserve the parts users want to keep.
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