DuplexBridge: Coordinating Understanding and Generation for Unified Image Editing
Organizations: University of Science and Technology of China · Wan Team, Alibaba Group
Abstract
Complex image editing requires faithful task interpretation and accurate execution, but a failed edit does not reveal which responsibility failed. We present DuplexBridge, which uses a unified model's own understanding capability to enhance prompts for its own generation capability, without an external understanding module. A source-grounded bridge specifies targets, final-state changes, and preservation constraints. Understanding is supervised on fidelity to the original request without observing the generated image; generation is supervised on execution of the condition it actually receives. Reciprocal trust checks selectively admit global task feedback to each role while retaining independently valid local supervision. We introduce CE-Bench, a 1,200-task benchmark measuring joint satisfaction of task-derived change and preservation requirements. Across three model configurations, the full system improves complete compliance over direct editors by 21.75-25.75 percentage points, with gains also observed on KRIS-Bench, RISEBench, ImgEdit, and GEdit-Bench. From a common supervised Wan-Image initialization, gated joint training reaches 77.08% complete compliance, compared with 70.92% without gates and 75.00% when generation-local supervision instead checks the original task with both gates retained. These results support distinct local responsibilities and selective shared feedback for joint understanding-generation adaptation.
Figures & tables
| Primary category | Secondary categories | |
| A. Source-Grounded | 300 | A1 Instance / Ordinal Grounding; A2 Spatial / Relational Grounding; A3 Attribute-Conditioned Selection; A4 Part / Region Grounding. |
| B. Text & Structured Content | 240 | B1 Exact Text Editing; B2 Multi-Text & Text Preservation; B3 Document / UI Layout Editing; B4 Numeric / Symbolic / Structured Visual Editing. |
| C. Reasoning-Grounded | 240 | C1 Visual Question-to-Edit; C2 Logical / Spatial / Quantitative Reasoning; C3 Temporal / Causal / Physical Inference; C4 Knowledge / Conceptual / Procedural Reasoning. |
| D. Coupled & Compositional | 240 | D1 Multi-Target Composition; D2 Dependent / Coupled Edits; D3 Relational Rearrangement; D4 Mixed Operations + Preservation. |
| E. Reference-Conditioned Multi-Image | 180 | E1 Entity / Subject Transfer; E2 Attribute / Appearance Transfer; E3 Pose / Layout / Structural Transfer; E4 Multi-Reference Composition & Reasoning. |
| Model | A | B | C | D | E | AC | Pres. | CCR |
| Commercial Models | ||||||||
| GPT-Image-1.5 | 83.00 | 78.33 | 72.92 | 82.50 | 68.89 | 93.47 | 94.12 | 77.83 |
| Gemini-3-pro-image-preview | 82.33 | 77.08 | 81.67 | 84.17 | 72.78 | 94.08 | 93.87 | 80.08 |
| Seedream 4.5 | 80.33 | 77.50 | 62.92 | 72.50 | 58.89 | 91.36 | 94.43 | 71.50 |
| Gemini-2.5-Flash-Image | 73.00 | 69.58 | 64.17 | 70.83 | 59.44 | 89.67 | 90.72 | 68.08 |
| Generation-only Editors | ||||||||
| Method | KRIS | RISE | ImgEdit | GEdit EN |
| PromptEnhancerV2 | 71.54 | 18.90 | 4.18 | 7.59 |
| DARS | 80.72 | 27.50 | 4.39 | 7.86 |
| BAGEL | 56.21 | 5.80 | 3.45 | 6.40 |
| + DuplexBridge | 76.48 | 26.11 | 4.04 | 7.41 |
| Qwen-2511 | 64.42 | 17.50 | 4.36 | 6.97 |
| + DuplexBridge | 82.16 | 31.11 | 4.43 | 7.89 |
| Method | Temporal | Causal | Spatial | Logical | Overall |
| BAGEL (B0) | 14.12 | 23.33 | 23.00 | 5.88 | 16.94 |
| BAGEL + DuplexBridge | 24.71 | 33.33 | 31.00 | 14.12 | 26.11 |
| Qwen-2511 (B0) | 21.18 | 26.67 | 29.00 | 9.41 | 21.94 |
| Qwen-2511 + DuplexBridge | 31.76 | 38.89 | 34.00 | 18.82 | 31.11 |
| Wan-Image-7B (B0) | 16.47 | 23.33 | 24.00 | 7.06 | 18.06 |
| Wan-Image-7B + DuplexBridge | 29.41 | 35.56 | 34.00 | 16.47 | 29.17 |
| Model | A | B | C | D | E | AC | Pres. | CCR |
| BAGEL (B0) | 68.67 | 49.58 | 47.92 | 62.92 | 47.78 | 83.91 | 88.63 | 56.42 |
| Qwen-2511 (B0) | 73.00 | 61.25 | 55.00 | 64.58 | 51.11 | 86.62 | 90.14 | 62.08 |
| Wan-Image-7B (B0) | 70.00 | 57.92 | 52.50 | 62.08 | 49.44 | 85.28 | 89.21 | 59.42 |
| Interface | CE AC | CE CCR |
| Fact-matched prose | 84.38 | 57.00 |
| Flat key-value | 84.16 | 56.67 |
| Flat JSON | 84.55 | 57.42 |
| Grouped key-value | 85.09 | 59.00 |
| CE-v1 grouped JSON | 85.28 | 59.42 |
| CE-v1 without redundant goal | 85.17 | 59.17 |
| Construction | Fidelity | Recall | Dup. | Human agr. | Retrained CCR |
| Same-contract prose rubric | 95.11 | 88.73 | 4.28 | 87.14 | 74.92 |
| Same-contract atomic reconstruction | 95.46 | 89.12 | 3.17 | 87.36 | 75.58 |
| Compiled execution checks | 98.21 | 91.68 | 0.73 | 87.92 | 77.08 |
| Variant | U/G RL | CE AC | CE CCR | Pres. | KRIS | RISE | ImgEdit | GEdit EN |
| Direct, no PE | –/– | 82.70 | 53.83 | 88.47 | 60.84 | 13.06 | 4.09 | 6.88 |
| Native PE | –/– | 83.86 | 56.67 | 88.92 | 63.41 | 15.83 | 4.11 | 6.97 |
| : matched SFT | –/– | 85.28 | 59.42 | 89.21 | 66.82 | 18.06 | 4.16 | 7.09 |
| U-only RL | /– | 87.96 | 66.67 | 88.74 | 73.28 | 24.44 | 4.17 | 7.21 |
| G-only RL | –/ | 88.61 | 67.50 | 92.28 | 71.94 | 21.94 | 4.31 | 7.52 |
| Dual-role local-only | / | – | 68.25 | – | – | – | – | – |
| Condition | CCR | Full minus control |
| Count-matched random gate | 71.33 | 5.75 |
| Group-structure-matched random gate | 72.25 | 4.83 |
| Original-task G-local source | 75.00 | 2.08 |
| Full: semantic gates + received-condition G-local | 77.08 | — |
| Gate | CE CCR | KRIS | RISE |
| Neither global gate | 70.92 | 76.27 | 26.11 |
| Prompt trust only | 74.17 | 78.62 | 28.06 |
| Execution trust only | 73.33 | 78.14 | 27.50 |
| Both global gates | 77.08 | 80.13 | 29.17 |
| Count-matched random | 71.33 | 76.48 | 26.11 |
| Soft semantic weighting | 76.33 | 79.76 | 28.89 |
| Interface | Ungated | Gated |
| Flat | 67.42 | 70.75 |
| Structured | 70.92 | 77.08 |
| Interaction: points | ||
| Gate | G-global cov. | Wrong / G-global | U-global cov. | Unexec. / U-global |
| Neither semantic gate | 93.60 | 18.59 | 91.40 | 27.41 |
| Prompt trust only | 71.20 | 2.90 | 91.40 | 27.41 |
| Execution trust only | 93.60 | 18.59 | 64.80 | 4.60 |
| Both trust gates | 71.20 | 2.90 | 64.80 | 4.60 |
| Count-matched random | 71.20 | 18.12 | 64.80 | 27.11 |
| Pair | CE CCR | KRIS | RISE |
| U0 G0 | 59.42 | 66.82 | 18.06 |
| Ut G0 | 65.92 | 72.48 | 22.22 |
| U0 Gt | 68.83 | 73.94 | 24.17 |
| Ut Gt | 77.08 | 80.13 | 29.17 |
| U CCR | F CCR | 95% interval | U AC | F AC | |||
| 3 | 300 | 85.00 | 90.33 | +5.33 | [+2.33, +8.33] | 95.00 | 96.78 |
| 5 | 360 | 74.44 | 80.83 | +6.39 | [+3.33, +9.44] | 89.78 | 92.33 |
| 7 | 360 | 66.39 | 74.44 | +8.06 | [+4.72, +11.39] | 88.53 | 92.58 |
| 9 | 180 | 49.44 | 52.78 | +3.33 | [-0.56, +7.22] | 83.15 | 84.26 |
| All | 1200 | 70.92 | 77.08 | +6.17 | [+4.50, +7.83] | 89.72 | 92.31 |
| RM | HPA | Hard | NLL | Brier | SwapErr | A/B gap | Latency |
| M0: Base direct | 77.6 | 66.5 | 0.489 | 0.158 | 0.058 | 2.2 | |
| M1: Explicit think | 82.3 | 75.8 | 0.377 | 0.120 | 0.045 | 1.3 | |
| M2: Preference SFT | 78.9 | 69.2 | 0.439 | 0.142 | 0.051 | 1.0 | |
| M3: Decision–reason | 79.9 | 71.2 | 0.409 | 0.133 | 0.046 | 0.8 | |
| M4: Hard KD | 80.4 | 72.3 | 0.501 | 0.154 | 0.062 | 1.6 | |
| M5: Soft KD | 81.7 | 74.8 | 0.385 | 0.122 | 0.041 | 0.6 |
| Category | M0 | M1 | M4 | M5 |
| Wrong target or ordinal | 70.0 | 78.3 | 75.8 | 78.3 |
| Near-miss text | 60.0 | 72.5 | 68.3 | 70.8 |
| Preservation damage | 69.2 | 76.7 | 73.3 | 78.3 |
| Coupled-edit omission | 61.7 | 73.3 | 68.3 | 70.8 |
| Visually good, task wrong | 71.7 | 78.3 | 75.8 | 75.8 |
| Reported overall | 66.5 | 75.8 | 72.3 | 74.8 |
| RM | MMRB2 edit pair acc. | EditReward | EditReward | EditReward |
| M0 | 66.2 | 57.2 | 35.9 | 10.8 |
| M1 | 71.8 | 61.8 | 44.9 | 16.6 |
| M2 | 67.1 | 58.3 | 37.8 | 11.9 |
| M3 | 68.6 | 59.6 | 40.4 | 13.3 |
| M4 | 69.3 | 60.1 | 41.5 | 13.8 |
| M5 | 70.6 | 61.0 | 43.5 | 15.8 |
| ID / RM | Gates | CCR | AC | Pres. |
| D0 / M0 | Off | 69.08 | 88.91 | 91.35 |
| D1 / M0 | On | 74.25 | 91.28 | 93.12 |
| D2 / M5 | Off | 70.92 | 89.72 | 91.82 |
| D3 / M5 | On | 77.08 | 92.31 | 93.86 |
| D4 / M1 | On | 77.50 | 92.42 | 93.73 |
| Method | Human CCR | Auto. CCR | Bias | Agree. | FA | FR | Human CCR bounds | |
| Direct | 195 | 53.33 | 54.36 | +1.03 | 88.72 | 13.19 | 9.62 | [52.0, 54.5] |
| Ungated | 196 | 69.39 | 70.92 | +1.53 | 91.33 | 16.67 | 5.15 | [68.0, 70.0] |
| Full | 197 | 76.14 | 76.65 | +0.51 | 93.40 | 14.89 | 4.00 | [75.0, 76.5] |
| Quantity | Estimate | 95% interval |
| Human gain | +6.70 | [+1.03, +12.37] |
| Automatic gain | +6.19 | [+1.55, +10.82] |
| Gain bias | -0.52 | [-3.61, +2.58] |
| Full comparison | Dimension | W/T/L | Unres. | Net | 95% interval |
| vs. ungated | Instruction | 65/102/30 | 3 | +17.77 | [+8.63, +26.90] |
| vs. ungated | Preservation | 38/122/37 | 3 | +0.51 | [-8.12, +9.14] |
| vs. ungated | Quality | 44/105/48 | 3 | -2.03 | [-11.68, +7.11] |
| vs. direct | Instruction | 89/83/25 | 3 | +32.49 | [+22.84, +42.13] |
| vs. direct | Preservation | 70/94/33 | 3 | +18.78 | [+9.14, +28.43] |
| vs. direct | Quality | 61/87/48 | 4 | +6.63 | [-3.57, +16.84] |
| Model | GenEval2 AM | GenEval2 GM | R2I | WISE-V | DPG |
| BAGEL + native CoT | 70.9 | 23.1 | 48.0 | 62.8 | 85.1 |
| BAGEL + DuplexBridge-T2I | 77.8 | 31.5 | 56.0 | 70.5 | 86.8 |
| Qwen-Image | 80.8 | 33.8 | 52.0 | 51.0 | 88.3 |
| Qwen-Image + DuplexBridge-T2I | 85.0 | 42.0 | 61.0 | 66.0 | 89.7 |
| Wan-Image-7B | 79.4 | 32.2 | 51.0 | 54.0 | 87.7 |
| Wan-Image-7B + DuplexBridge-T2I | 84.2 | 40.6 | 59.5 | 64.5 | 89.3 |
Image Editing
Image editing changes selected visual content while preserving the parts of an image that should remain unchanged.
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