EGM-8B

Model Summary

EGM-Qwen3-VL-8B is the flagship model of the EGM (Efficient Visual Grounding Language Models) family. It is built on top of Qwen3-VL-8B-Thinking and trained with a two-stage pipeline: supervised fine-tuning (SFT) followed by reinforcement learning (RL) using GRPO (Group Relative Policy Optimization).

EGM demonstrates that by increasing test-time computation, small vision-language models can outperform much larger models in visual grounding tasks while being significantly faster at inference.

Key Results

• 91.4 average IoU on the RefCOCO benchmark (vs. 87.8 for the base Qwen3-VL-8B-Thinking)
• +3.6 IoU improvement over the base model
• Outperforms Qwen3-VL-235B-A22B-Instruct (88.2 avg IoU) and Qwen3-VL-235B-A22B-Thinking (90.7 avg IoU)
• 5.9x faster inference than Qwen3-VL-235B (737ms vs 4,320ms average latency)
• 18.9x faster than Qwen3-VL-235B-Thinking

RefCOCO Benchmark Results

How It Works

VLMs of different sizes often share the same visual encoder. Small models fall behind large models primarily due to a gap in text understanding capabilities — 62.8% of small model errors stem from complex prompts with multiple relational descriptions. EGM mitigates this gap by generating many mid-quality tokens (from small models) to match the performance of large VLMs that produce fewer but more expensive tokens.

Training Pipeline

1. SFT Stage: A proprietary VLM generates detailed chain-of-thought reasoning steps for visual grounding training data. The base model is fine-tuned on this data. The SFT checkpoint is available as nvidia/EGM-8B-SFT.
2. RL Stage: GRPO is applied with a reward function combining IoU and task success metrics, further improving grounding accuracy.

Quickstart

Download

bash
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pip install -U huggingface_hub
huggingface-cli download nvidia/EGM-8B --local-dir ./models/EGM-8B

Inference with SGLang

Launch the server:

bash
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pip install "sglang[all]>=0.5.5"

python -m sglang.launch_server \
    --model-path nvidia/EGM-8B \
    --chat-template=qwen3-vl \
    --port 30000

Send a visual grounding request:

python
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import openai
import base64

client = openai.Client(base_url="http://127.0.0.1:30000/v1", api_key="EMPTY")

# Load a local image as base64
with open("example.jpg", "rb") as f:
    image_base64 = base64.b64encode(f.read()).decode("utf-8")

response = client.chat.completions.create(
    model="nvidia/EGM-8B",
    messages=[
        {
            "role": "user",
            "content": [
                {"type": "image_url", "image_url": {"url": f"data:image/jpeg;base64,{image_base64}"}},
                {"type": "text", "text": "Please provide the bounding box coordinate of the region this sentence describes: the person on the left."},
            ],
        }
    ],
    temperature=0.6,
    top_p=0.95,
    max_tokens=8192,
)
print(response.choices[0].message.content)

Model Architecture

Citation

bibtex
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@article{zhan2026EGM,
    author = {Zhan, Guanqi and Li, Changye and Liu, Zhijian and Lu, Yao and Wu, Yi and Han, Song and Zhu, Ligeng},
    title = {EGM: Efficient Visual Grounding Language Models},
    booktitle = {arXiv},
    year = {2026}
}

Acknowledgment

This repository benefits from Qwen3-VL, InternVL, verl and verl-internvl.