---
license: apache-2.0
library_name: realesrgan
pipeline_tag: image-to-image
tags:
  - image-upscaling
  - super-resolution
  - realesrgan
  - esrgan
  - post-processing
  - image-enhancement
---

<!-- README Version: v1.3 -->

# FLUX Upscale Models Collection v1.3

This repository contains Real-ESRGAN upscale models for post-processing and enhancing generated images. These models can upscale images by 2x or 4x while adding fine details and improving sharpness.

## Model Description

Real-ESRGAN (Real Enhanced Super-Resolution Generative Adversarial Networks) models for high-quality image upscaling. These models are commonly used as post-processing steps for AI-generated images to increase resolution and enhance details.

**Key Capabilities**:
- 2x and 4x image upscaling
- Detail enhancement and sharpening
- Noise reduction and artifact removal
- Optimized for AI-generated images
- CPU and GPU compatible

## Repository Contents

**Total Size**: ~192MB

### Upscale Models (upscale_models/)
- `4x-UltraSharp.pth` - 64MB - 4x upscaling with ultra-sharp detail enhancement
- `RealESRGAN-x2plus.pth` - 64MB - 2x upscaling model
- `RealESRGAN-x4plus.pth` - 64MB - 4x upscaling model

## Hardware Requirements

- **VRAM**: 4GB+ recommended for GPU inference
- **Disk Space**: 192MB
- **Memory**: 8GB+ system RAM recommended
- **Compatible with**: CPU or GPU inference (CUDA, ROCm, or CPU)

## Usage Examples

### Basic Usage with Real-ESRGAN

```python
from basicsr.archs.rrdbnet_arch import RRDBNet
from realesrgan import RealESRGANer
import cv2

# Load the upscaler model
model = RRDBNet(num_in_ch=3, num_out_ch=3, num_feat=64, num_block=23, num_grow_ch=32)

upsampler = RealESRGANer(
    scale=4,
    model_path="E:\\huggingface\\flux-upscale\\upscale_models\\4x-UltraSharp.pth",
    model=model,
    tile=0,
    tile_pad=10,
    pre_pad=0,
    half=True  # Use FP16 for faster inference on GPU
)

# Load and upscale an image
img = cv2.imread("input.png", cv2.IMREAD_COLOR)
output, _ = upsampler.enhance(img, outscale=4)
cv2.imwrite("output_upscaled.png", output)
```

### Using with FLUX Pipeline

```python
from diffusers import FluxPipeline
from realesrgan import RealESRGANer
from basicsr.archs.rrdbnet_arch import RRDBNet
import torch
import numpy as np

# Generate image with FLUX
pipe = FluxPipeline.from_pretrained(
    "E:\\huggingface\\flux-dev-fp16",
    torch_dtype=torch.float16
)
pipe.to("cuda")

image = pipe(
    prompt="a beautiful landscape with mountains",
    num_inference_steps=30
).images[0]

# Convert PIL to numpy/cv2 format
img_array = np.array(image)

# Initialize upscaler
model = RRDBNet(num_in_ch=3, num_out_ch=3, num_feat=64, num_block=23, num_grow_ch=32)
upsampler = RealESRGANer(
    scale=4,
    model_path="E:\\huggingface\\flux-upscale\\upscale_models\\4x-UltraSharp.pth",
    model=model,
    half=True
)

# Upscale the generated image
upscaled, _ = upsampler.enhance(img_array, outscale=4)

# Save result
import cv2
cv2.imwrite("flux_upscaled_4x.png", upscaled)
```

### Tiled Processing for Large Images

```python
from basicsr.archs.rrdbnet_arch import RRDBNet
from realesrgan import RealESRGANer
import cv2

# Configure for large images with tiling
model = RRDBNet(num_in_ch=3, num_out_ch=3, num_feat=64, num_block=23, num_grow_ch=32)

upsampler = RealESRGANer(
    scale=4,
    model_path="E:\\huggingface\\flux-upscale\\upscale_models\\RealESRGAN_x4plus.pth",
    model=model,
    tile=512,      # Process in 512x512 tiles
    tile_pad=10,   # Padding to avoid seams
    pre_pad=0,
    half=True
)

# Process large image
img = cv2.imread("large_image.png", cv2.IMREAD_COLOR)
output, _ = upsampler.enhance(img, outscale=4)
cv2.imwrite("large_upscaled.png", output)
```

## Model Comparison

| Model | Scale | Best For | File Size | Speed |
|-------|-------|----------|-----------|-------|
| 4x-UltraSharp | 4x | Sharp details, AI-generated images | 64MB | Moderate |
| RealESRGAN_x2plus | 2x | Moderate upscaling, faster processing | 64MB | Fast |
| RealESRGAN_x4plus | 4x | General purpose 4x upscaling | 64MB | Moderate |

**Model Selection Guide**:
- **4x-UltraSharp**: Best for AI-generated images needing maximum sharpness
- **RealESRGAN_x2plus**: Quick 2x upscaling with balanced quality
- **RealESRGAN_x4plus**: General-purpose 4x upscaling for various image types

## Model Specifications

- **Architecture**: RRDB (Residual in Residual Dense Block)
- **Input Channels**: 3 (RGB)
- **Output Channels**: 3 (RGB)
- **Feature Dimensions**: 64
- **Network Blocks**: 23 (standard configuration)
- **Growth Channels**: 32
- **Format**: PyTorch `.pth` files
- **Precision**: FP32 (supports FP16 inference)

## Performance Tips

- **GPU Acceleration**: Use `half=True` for FP16 inference on compatible GPUs (approximately 2x faster)
- **Tiling for VRAM**: Enable tiling with `tile=512` to reduce VRAM usage for large images
- **Tile Padding**: Use `tile_pad=10` to minimize visible seams between tiles
- **Batch Processing**: Process multiple images sequentially to amortize model loading time
- **CPU Fallback**: Models work on CPU but will be significantly slower (~10-20x)
- **Optimal Scale**: Use 2x for faster processing, 4x for maximum detail enhancement
- **Input Quality**: Better input images produce better upscaling results
- **File Formats**: Use lossless formats (PNG) for best quality preservation

## Use Cases

- Post-processing AI-generated images from FLUX.1, Stable Diffusion, etc.
- Enhancing FLUX.1-dev outputs for high-resolution prints
- Increasing resolution of generated artwork for commercial use
- Adding fine details to synthetic images
- Print preparation for generated images (posters, canvas prints)
- Upscaling video frames for AI video generation pipelines
- Restoring and enhancing low-resolution generated content

## Installation

```bash
pip install realesrgan basicsr
```

**Dependencies**:
- Python 3.8+
- PyTorch 1.7+
- basicsr
- realesrgan
- opencv-python
- numpy

## License

These models are released under the Apache 2.0 license.

## Citation

```bibtex
@InProceedings{wang2021realesrgan,
    author    = {Xintao Wang and Liangbin Xie and Chao Dong and Ying Shan},
    title     = {Real-ESRGAN: Training Real-World Blind Super-Resolution with Pure Synthetic Data},
    booktitle = {International Conference on Computer Vision Workshops (ICCVW)},
    year      = {2021}
}
```

## Links and Resources

- **Real-ESRGAN Paper**: [arXiv:2107.10833](https://arxiv.org/abs/2107.10833)
- **Official Repository**: [xinntao/Real-ESRGAN](https://github.com/xinntao/Real-ESRGAN)
- **BasicSR Library**: [xinntao/BasicSR](https://github.com/xinntao/BasicSR)
- **Hugging Face**: [Real-ESRGAN Models](https://huggingface.co/models?other=real-esrgan)
- **Model Downloads**: Available through official Real-ESRGAN releases

## Model Card Contact

For questions about Real-ESRGAN models, refer to the official Real-ESRGAN repository and documentation at https://github.com/xinntao/Real-ESRGAN