---
# For reference on model card metadata, see the spec: https://github.com/huggingface/hub-docs/blob/main/modelcard.md?plain=1
# Doc / guide: https://huggingface.co/docs/hub/model-cards
{
  "library_name": "transformers",
  "pipeline_tag": "image-to-text",
  "license": "apache-2.0",
  "tags": [
    "vision-language",
    "image-captioning",
    "SmolVLM",
    "LoRA",
    "QLoRA",
    "COCO",
    "peft",
    "accelerate"
  ],
  "base_model": "HuggingFaceTB/SmolVLM-Instruct",
  "datasets": ["jxie/coco_captions"],
  "language": ["en"],
  "widget": [
    {
      "text": "Give a concise caption.",
      "src": "https://images.cocodataset.org/val2014/COCO_val2014_000000522418.jpg"
    }
  ]
}
---

# Model Card for **Image-Captioning-VLM (SmolVLM + COCO, LoRA/QLoRA)**

This repository provides a compact **vision–language image captioning model** built by fine-tuning **SmolVLM-Instruct** with **LoRA/QLoRA** adapters on the **MS COCO Captions** dataset. The goal is to offer an easy-to-train, memory‑efficient captioner for research, data labeling, and diffusion training workflows while keeping the **vision tower frozen** and adapting the language/cross‑modal components.

> **TL;DR**
>
> - Base: `HuggingFaceTB/SmolVLM-Instruct` (Apache-2.0).  
> - Training data: `jxie/coco_captions` (English captions).  
> - Method: LoRA/QLoRA SFT; **vision encoder frozen**.  
> - Intended use: generate concise or descriptive captions for general images.  
> - Not intended for high-stakes or safety-critical uses.

---

## Model Details

### Model Description

- **Developed by:** *Amirhossein Yousefi* (GitHub: `amirhossein-yousefi`)
- **Model type:** Vision–Language (**image → text**) captioning model with LoRA/QLoRA adapters on top of **SmolVLM-Instruct**
- **Language(s):** English
- **License:** **Apache-2.0** for the released model artifacts (inherits from the base model’s license); dataset retains its own license (see *Training Data*)
- **Finetuned from:** `HuggingFaceTB/SmolVLM-Instruct`

SmolVLM couples a **shape-optimized SigLIP** vision tower with a compact **SmolLM2** decoder via a multimodal projector and runs via `AutoModelForVision2Seq`. This project fine-tunes the language-side with LoRA/QLoRA while **freezing the vision tower** to keep memory use low and training simple.

### Model Sources

- **Repository:** https://github.com/amirhossein-yousefi/Image-Captioning-VLM
- **Base model card:** https://huggingface.co/HuggingFaceTB/SmolVLM-Instruct
- **Base technical report :** https://arxiv.org/abs/2504.05299 (SmolVLM)
- **Dataset (training):** https://huggingface.co/datasets/jxie/coco_captions

---

## Uses

### Direct Use

- Generate **concise** or **descriptive** captions for natural images.
- Provide **alt text**/accessibility descriptions (human review recommended).
- Produce captions for **vision dataset bootstrapping** or **diffusion training** pipelines.

**Quickstart (inference script from this repo):**

```bash
python inference_vlm.py \
  --base_model_id HuggingFaceTB/SmolVLM-Instruct \
  --adapter_dir outputs/smolvlm-coco-lora \
  --image https://images.cocodataset.org/val2014/COCO_val2014_000000522418.jpg \
  --prompt "Give a concise caption."
```

**Programmatic example (PEFT LoRA):**

```python
import torch
from PIL import Image
from transformers import AutoProcessor, AutoModelForVision2Seq
from peft import PeftModel

device = "cuda" if torch.cuda.is_available() else "cpu"
base = "HuggingFaceTB/SmolVLM-Instruct"
adapter_dir = "outputs/smolvlm-coco-lora"  # path from training

processor = AutoProcessor.from_pretrained(base)
model = AutoModelForVision2Seq.from_pretrained(
    base, torch_dtype=torch.bfloat16 if device == "cuda" else torch.float32
).to(device)

# Load LoRA/QLoRA adapter
model = PeftModel.from_pretrained(model, adapter_dir).to(device)
model.eval()

image = Image.open("sample.jpg").convert("RGB")
messages = [{"role": "user",
             "content": [{"type": "image"},
                         {"type": "text", "text": "Give a concise caption."}]}]
prompt = processor.apply_chat_template(messages, add_generation_prompt=True)

inputs = processor(text=prompt, images=[image], return_tensors="pt").to(device)
ids = model.generate(**inputs, max_new_tokens=64)
print(processor.batch_decode(ids, skip_special_tokens=True)[0])
```

### Downstream Use

- As a **captioning stage** within multi-step data pipelines (e.g., labeling, retrieval augmentation, dataset curation).
- As a starting point for **continued fine-tuning** on specialized domains (e.g., medical imagery, artwork) with domain-appropriate data and review.

### Out-of-Scope Use

- **High-stakes** or **safety-critical** settings (medical, legal, surveillance, credit decisions, etc.).
- Automated systems where **factuality, fairness, or safety** must be guaranteed without **human in the loop**.
- Parsing small text (OCR) or reading sensitive PII from images; this model is not optimized for OCR.

---

## Bias, Risks, and Limitations

- **Data bias:** COCO captions are predominantly English and reflect biases of their sources; generated captions may mirror societal stereotypes.
- **Content coverage:** General-purpose images work best; performance may degrade on domains underrepresented in COCO (e.g., medical scans, satellite imagery).
- **Safety:** Captions may occasionally be **inaccurate**, **overconfident**, or **hallucinated**. Always review before downstream use, especially for accessibility.

### Recommendations

- Keep a **human in the loop** for sensitive or impactful applications.
- When adapting to new domains, curate **diverse, representative** training sets and evaluate with domain-specific metrics and audits.
- Log model outputs and collect review feedback to iteratively improve quality.

---

## How to Get Started with the Model

**Environment setup**

```bash
python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
# (If on NVIDIA & want QLoRA) ensure bitsandbytes is installed; or use: --use_qlora false
```

**Fine-tune (LoRA/QLoRA; frozen vision tower)**

```bash
python train_vlm_sft.py \
  --base_model_id HuggingFaceTB/SmolVLM-Instruct \
  --dataset_id jxie/coco_captions \
  --output_dir outputs/smolvlm-coco-lora \
  --epochs 1 --batch_size 2 --grad_accum 8 \
  --max_seq_len 1024 --image_longest_edge 1536
```

---

## Training Details

### Training Data

- **Dataset:** `jxie/coco_captions` (English captions for MS COCO images).  
- **Notes:** COCO provides **~617k** caption examples with **5 captions per image**; images come from Flickr with their own terms. Please review the dataset card and the original COCO license/terms before use.

### Training Procedure

#### Preprocessing

- Images are resized with **longest_edge = 1536** (consistent with SmolVLM’s 384×384 patching strategy at N=4).
- Text sequences truncated/padded to **max_seq_len = 1024**.

#### Training Hyperparameters

- **Regime:** Supervised fine-tuning with **LoRA** (or **QLoRA**) on the language-side parameters; **vision tower frozen**.
- **Example CLI:** see above. Mixed precision (`bf16` on CUDA) recommended if available.

#### Speeds, Sizes, Times

- The base SmolVLM reports **~5 GB min GPU RAM** for inference; fine-tuning requires more VRAM depending on batch size/sequence length. See the base card for details.

---

## Evaluation
### 📊 Score card(on subsample of main data)

**All scores increase with higher values (↑).** For visualization, `CIDEr` is shown ×100 in the chart to match the 0–100 scale of other metrics.

| Split        | CIDEr | CLIPScore | BLEU-4 | METEOR | ROUGE-L | BERTScore-F1 | Images |
|:-------------|------:|----------:|-------:|-------:|--------:|-------------:|------:|
| **Test**      | 0.560 | 30.830    | 15.73  | 47.84  | 45.18   | 91.73        | 1000  |
| **Validation**| 0.540 | 31.068    | 16.01  | 48.28  | 45.11   | 91.80        | 1000  |


### Quick read on the metrics

- **CIDEr** — consensus with human captions; higher is better for human-like phrasing (0–>1 typical).  
- **CLIPScore** — reference-free image–text compatibility via CLIP’s cosine similarity (commonly rescaled).  
- **BLEU‑4** — 4‑gram precision with brevity penalty (lexical match).  
- **METEOR** — unigram match with stemming/synonyms, emphasizes recall.  
- **ROUGE‑L** — longest common subsequence overlap (structure/recall‑leaning).  
- **BERTScore‑F1** — semantic similarity using contextual embeddings.


### Testing Data, Factors & Metrics

#### Testing Data

- Hold out a portion of **COCO val** (e.g., `val2014`) or custom images for qualitative/quantitative evaluation.

#### Factors

- **Image domain** (indoor/outdoor), **object density**, **scene complexity**, and **presence of small text** (OCR-like) can affect performance.

#### Metrics
- Strong **semantic alignment** (BERTScore-F1 ≈ **91.8** on *val*), and balanced lexical overlap (BLEU-4 ≈ **16.0**).
- **CIDEr** is slightly higher on *test* (0.560) vs. *val* (0.540); other metrics are near parity across splits.
- Trained & evaluated with the minimal pipeline in the repo (LoRA/QLoRA-ready).
- This repo includes `eval_caption_metric.py` scaffolding.

### Results

- Publish your scores here after running the evaluation script (e.g., CIDEr, BLEU-4) and include qualitative examples.


#### Summary

- The LoRA/QLoRA approach provides **memory‑efficient adaptation** while preserving the strong generalization of SmolVLM on image–text tasks.

---

## Model Examination 

- You may inspect token attributions or visualize attention over image regions using third-party tools; no built‑in interpretability tooling is shipped here.

---

## 🖥️ Training Hardware & Environment

- **Device:** Laptop (Windows, WDDM driver model)  
- **GPU:** NVIDIA GeForce **RTX 3080 Ti Laptop GPU** (16 GB VRAM)  
- **Driver:** **576.52**  
- **CUDA (driver):** **12.9**  
- **PyTorch:** **2.8.0+cu129**  
- **CUDA available:** ✅ 


## 📊 Training Metrics

- **Total FLOPs (training):** `26,387,224,652,152,830`  
- **Training runtime:** `5,664.0825` seconds  
---

## Technical Specifications

### Model Architecture and Objective

- **Architecture:** SmolVLM-style VLM with **SigLIP** vision tower, **SmolLM2** decoder, and a **multimodal projector**; trained here via **SFT with LoRA/QLoRA** for **image captioning**.
- **Objective:** Next-token generation conditioned on image tokens + text prompt (image → text).

### Compute Infrastructure

#### Hardware

- Works on consumer GPUs for inference; fine‑tuning VRAM depends on adapter choice and batch size.

#### Software

- Python, PyTorch, `transformers`, `peft`, `accelerate`, `datasets`, `evaluate`, optional `bitsandbytes` for QLoRA.

---

## Citation

If you use this repository or the resulting model, please cite:

**BibTeX:**

```bibtex
@software{ImageCaptioningVLM2025,
  author = {Yousefi, Amir Hossein},
  title = {Image-Captioning-VLM: LoRA/QLoRA fine-tuning of SmolVLM for image captioning},
  year = {2025},
  url = {https://github.com/amirhossein-yousefi/Image-Captioning-VLM}
}
```

Also cite the **base model** and **dataset** as appropriate (see their pages).

**APA:**

Yousefi, A. H. (2025). *Image-Captioning-VLM: LoRA/QLoRA fine-tuning of SmolVLM for image captioning* [Computer software]. https://github.com/amirhossein-yousefi/Image-Captioning-VLM

---

## Glossary 

- **LoRA/QLoRA:** Low‑Rank (Quantized) Adapters that enable parameter‑efficient fine‑tuning.
- **Vision tower:** The vision encoder (SigLIP) that turns image patches into tokens.
- **SFT:** Supervised Fine‑Tuning.

---

## More Information 

- For issues and feature requests, open a GitHub issue on the repository.

---

## Model Card Authors 

- Amirhossein Yousefi (maintainer)
- Contributors welcome (via PRs)

---

## Model Card Contact

- Open an issue: https://github.com/amirhossein-yousefi/Image-Captioning-VLM/issues