Model description
Multimodal on-policy distillation normally transfers the complete correction
proposed by a privileged teacher. That correction can mix visual evidence with
language preferences, formatting behavior, and other teacher-specific effects.
VAD instead asks which part of the correction is attributable to a controlled
change in the relevant visual evidence.
At each student-generated prefix, VAD evaluates the same fixed teacher with the
evidence present and removed. The resulting distributional response provides a
signed proxy direction for visual support and refutation. VAD projects the
teacher correction onto this direction, allocates separate budgets to supported
and refuted candidate tokens, and reconstructs a target around the full-image
student distribution. The reconstructed target supplies the primary JSD
supervision, while the original privileged teacher contributes only a weak
stability regularizer.
The auxiliary teacher views are used only during training. Inference requires a
single image and uses the standard Qwen3.5-9B architecture.
Checkpoint identity
Table with columns: Item, Value| Item | Value |
|---|
| Base model | Qwen/Qwen3.5-9B |
| Internal run | VC-OPD-Qwen35-9B-BASVCtau07-fixedTeacher-bs96-mb96-eta01-gpu030-eval15-ctx9216-2epoch-step130-restart-20260628_183144 |
| Released checkpoint | global_step_70 |
| Primary supervision | Symmetric JSD, α=0.5 |
| VAD target | Branch-separated, budgeted visual support and refutation |
| Positive-branch cap | τ+=0.7 |
| Weak teacher-regularizer weight | λ=0.1 |
| Projection stabilizer | ζ=10−3 |
| Coordinate shift bound | c=20 |
| Teacher | Frozen copy of the initial Qwen3.5-9B student |
| Training schedule | 2 epochs / 130 steps; checkpoint selected at step 70 |
| Learning rate | 2×10−6 |
| Train batch size | 96 |
| Rollouts per prompt | 8 |
| Maximum prompt / response length | 8192 / 1024 tokens |
| Training context length | 9,216 tokens |
| Training GPUs | 8 |
| Random seed | 42 |
Training used 6,241 synthetic visual question-answering examples. Each example
contains a full image, an evidence-present crop, and a spatially matched
evidence-degraded crop. The primary token-level target is evaluated over the
student top-100 support plus a tail bucket. During training, VStar, ZoomBench,
HRBench-4K, and HRBench-8K were monitored every 15 optimization steps; the
official results below were computed separately after training.
Evaluation
We evaluated this checkpoint using the Vision-OPD official inference and
accuracy pipeline with openai/gpt-oss-120b as judge. Inference used
max_model_len=32768, MAX_TOKENS=8192, ENABLE_THINKING=False, and seed 42.
The judge used temperature 0. All answer and judge files passed the completeness
audit, with no non-canonical final judge labels.
Table with columns: Benchmark, Accuracy| Benchmark | Accuracy |
|---|
| VStar | 94.76 |
| ZoomBench | 62.49 |
| HRBench-4K | 87.88 |
| HRBench-8K | 85.75 |
| MME-RealWorld-EN | 76.56 |
| MME-RealWorld-CN | 72.13 |
| Unweighted average | 79.93 |
These results are specific to this checkpoint, benchmark versions, inference
configuration, and judge protocol.
Serving with vLLM
Use a recent vLLM release with Qwen3.5 support:
vllm serve zhangkangning/VAD_for_Qwen3.5-9b \
--host 0.0.0.0 \
--port 8000 \
--served-model-name VAD-Qwen3.5-9B \
--trust-remote-code \
--tensor-parallel-size 2 \
--max-model-len 32768 \
--gpu-memory-utilization 0.90
Adjust --tensor-parallel-size to the available hardware. A single
high-memory GPU can use --tensor-parallel-size 1.
Example OpenAI-compatible multimodal request:
from openai import OpenAI
client = OpenAI(base_url="http://127.0.0.1:8000/v1", api_key="EMPTY")
response = client.chat.completions.create(
model="VAD-Qwen3.5-9B",
messages=[
{
"role": "user",
"content": [
{
"type": "image_url",
"image_url": {"url": "https://example.com/image.jpg"},
},
{
"type": "text",
"text": "Describe the fine-grained visual details.",
},
],
}
],
max_tokens=1024,
temperature=0,
extra_body={"chat_template_kwargs": {"enable_thinking": False}},
)
print(response.choices[0].message.content)
Replace the placeholder image URL with an accessible image URL or a supported
data URL.
Intended use and limitations
- This checkpoint is intended for research on multimodal perception,
fine-grained visual question answering, and on-policy distillation.
- Performance outside the reported visual benchmarks, including broad language
capability, safety, bias, and robustness, has not been comprehensively
evaluated.
- Like other vision-language models, it may produce incorrect or unsupported
answers. Independently verify outputs in high-stakes settings.
- The model inherits the capabilities and limitations of Qwen3.5-9B.
License
The checkpoint is released under the Apache License 2.0, consistent with the
base model. Users must also comply with the
Qwen3.5-9B license.
Citation
The public paper identifier and final citation will be added when available.
No provisional bibliographic entry is provided here.