SigLIP-Qwen-1.7B-COCO-Captioner

Model Description

This is a custom Multimodal Large Language Model (MLLM) designed for Image Captioning. It combines a state-of-the-art vision encoder with a lightweight LLM using a custom Q-Former style adapter.

• Vision Encoder: google/siglip2-base-patch16-512 (Frozen)
• LLM: Qwen/Qwen3-1.7B (LoRA Fine-tuned)
• Adapter: Custom Multi-layer Cross-Attention Adapter
• Parameters: ~1.9B Total (Active Parameters: ~30M via LoRA & Adapter)

Intended Uses & Limitations

• Intended Use: Generating descriptive captions for natural images. It excels at recognizing common objects found in the COCO dataset (people, vehicles, animals, household items).
• Limitations:
  • Domain Specificity: Trained primarily on COCO. It may struggle with "out-of-domain" objects (e.g., specific plant species, medical images, or OCR text) that are not present in the COCO classes.
  • Hallucination: Like all MLLMs, it may occasionally describe objects that are not present, especially in complex or blurry images.

Training and Evaluation Data

• Training Data: MS COCO 2017 Captioning Dataset (~118k images).
• Evaluation Data:
  • COCO Validation: Achieved CIDEr Score: ~0.866
  • NoCaps Validation: Achieved CIDEr Score: ~0.50 (Zero-shot generalization)

Training Procedure

The model was trained in two stages on an NVIDIA H100 GPU:

1. Stage 1 (Alignment): Pre-trained on Flickr30k to align visual features with text.
2. Stage 2 (Fine-tuning): Fine-tuned on COCO 2017 for 10 epochs.
   • Optimizer: AdamW
   • Learning Rate: 2e-5 (decayed to 5e-6 for refinement)
   • Batch Size: 64 (Effective batch size 128 via gradient accumulation)
   • Precision: bfloat16

💻 How to Use (Required Code)

Note: This model uses a custom architecture code (model_architecture.py) which is included in the repository. You must load the architecture class before loading the weights.

import torch
from transformers import AutoTokenizer
from huggingface_hub import hf_hub_download
from model_architecture import MultiModalQwen, MMConfig
from PIL import Image
from torchvision import transforms

# 1. Initialize Configuration & Model
cfg = MMConfig()
model = MultiModalQwen(cfg)

# 2. Download and Load Weights
ckpt_path = hf_hub_download(repo_id="SatyaJaiss/SigLIP-Qwen-1.7B-COCO-Captioner", filename="pytorch_model.bin")

state_dict = torch.load(ckpt_path, map_location="cpu")
model.load_state_dict(state_dict)
model.to("cuda").eval()

# 3. Load Tokenizer
tokenizer = AutoTokenizer.from_pretrained("SatyaJaiss/SigLIP-Qwen-1.7B-COCO-Captioner")

# 4. Prepare Image
image_path = "path/to/your/image.jpg"
image = Image.open(image_path).convert("RGB")

transform = transforms.Compose([
    transforms.Resize((512, 512)),
    transforms.ToTensor(),
    transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5])
])
pixel_values = transform(image).unsqueeze(0).to("cuda").bfloat16()

# 5. Generate Caption
prompts = ["Caption: "]
inputs = tokenizer(prompts, return_tensors="pt").to("cuda")

with torch.no_grad():
    gen_ids = model.generate(
        pixel_values=pixel_values,
        input_ids=inputs.input_ids,
        attention_mask=inputs.attention_mask,
        max_new_tokens=30,
        do_sample=False
    )

print(tokenizer.decode(gen_ids[0], skip_special_tokens=True))