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skylenage-ai/SkyJM-Edit-4B

sourceHugging Faceapache-2.0updated 28d agoView on Hugging Face
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SkyJM(RubricRM) is a reward model for visual generation, covering both text-to-image generation and image editing. Given a prompt and two candidate images, it predicts which one better satisfies the instruction. RubricRM performs the following in a single forward pass:

  • —Dynamically produces an evaluation rubric conditioned on the prompt — including evaluation dimensions, per-dimension weights, and graded scoring descriptors;
  • —Scores both candidate images at the dimension level under that rubric;
  • —Aggregates the dimension scores via the rubric weights to derive the final preference.

We release two model sizes built on the Qwen3.5 backbone:

  • —SkyJM-Gen-4B / SkyJM-Gen-9B — for text-to-image generation
  • —SkyJM-Edit-4B / SkyJM-Edit-9B — for image editing

Performance

Text-to-image generation

ModelMMRB2GenAI-BenchGenAI-Bench-Verified
Proprietary MLLMs
Claude Sonnet 4.670.865.875.3
GPT-5.467.564.274.2
Gemini 2.5 Pro70.567.877.4
Gemini 3.1 Pro74.473.984.8
Open-source MLLMs
Qwen3-VL-8B61.263.372.5
Qwen3-VL-235B-A22B66.661.569.7
Qwen3.5-9B66.363.370.7
Qwen3.5-397B-A17B72.766.277.0
Reward Models
HPSv255.068.878.1
PickScore57.670.079.2
HPSv360.270.981.0
UnifiedReward-9B57.969.272.8
UnifiedReward-Think-9B65.572.881.7
UnifiedReward-Flex-8B69.2<u>73.4</u><u>84.2</u>
SkyJM-Gen-4B (Ours)<u>70.5</u>73.283.1
SkyJM-Gen-9B (Ours)72.074.184.5

Image editing

ModelMMRB2EditReward-ERB AvgEditScore-ERB Avg
Proprietary MLLMs
Claude Sonnet 4.671.744.179.3
GPT-5.468.542.574.6
Gemini 2.5 Pro71.342.275.2
Gemini 3.1 Pro74.945.081.6
Open-source MLLMs
Qwen3-VL-8B63.440.976.9
Qwen3-VL-235B-A22B64.834.678.8
Qwen3.5-9B64.437.472.0
Qwen3.5-397B-A17B73.743.981.2
Reward Models
EditReward-7B67.238.478.3
EditScore-7B55.628.861.9
SkyJM-Edit-4B (Ours)<u>73.2</u><u>45.5</u><u>85.5</u>
SkyJM-Edit-9B (Ours)75.446.485.6

Training Strategy

Stage 1: Rubric-trajectory SFT. We use Gemini 3.1 Pro to synthesize rubric-based evaluation trajectories conditioned on human preference labels, then filter them with structural and label-consistency checks for SFT.

Stage 2: Dimension-level GRPO. During RL, we fix the rubric and optimize only the scoring process using rewards based on per-dimension score gaps, with saturated-group filtering to suppress noisy low-variance updates.

Quick Start

For detailed usage instructions, installation guide, and inference examples (supporting both vLLM and Transformers backends), please refer to the official inference framework:

[SKYLENAGE-JUDGER](https://github.com/SKYLENAGE-AI/SKYLENAGE-JUDGER) — Unified inference framework for SkyJM judge models.

Link

Citation

If you find this model useful, please cite our paper:

bibtex
@misc{kan2026rubricrmgenerativerewardmodeling,
      title={RubricRM: Generative Reward Modeling via Dynamic Rubrics for Image Generation and Editing}, 
      author={Zijian Kan and Wei Wang and Long Luo and Bing Zhao and Xuan Ren and Weixu Qiao and Wenbo Li and Hu Wei and Lin Qu},
      year={2026},
      eprint={2608.26956},
      archivePrefix={arXiv},
      primaryClass={cs.CV},
      url={https://arxiv.org/abs/2608.26956}, 
}