---
library_name: keras
license: mit
language:
- en
pipeline_tag: image-to-image
---
# Autoencoder Grayscale2Color Landscape 🛡️

[![huggingface-hub](https://img.shields.io/badge/huggingface--hub-orange.svg?logo=huggingface)](https://huggingface.co/docs/hub)
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[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)

## Introduction
Transform grayscale landscape images into vibrant, full-color visuals with this autoencoder model. Built from scratch, this project leverages deep learning to predict color channels (a*b* in L*a*b* color space) from grayscale inputs, delivering impressive results with a sleek, minimalist design. 🌄

## Key Features
- 📸 Converts grayscale landscape images to vivid RGB.
- 🧠 Custom autoencoder with spatial attention for enhanced detail.
- ⚡ Optimized for high-quality inference at 512x512 resolution.
- 📊 Achieves a PSNR of 21.70 on the validation set.

## Notebook
Explore the implementation in our Jupyter notebook:  
[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/#fileId=https://huggingface.co/danhtran2mind/autoencoder-grayscale2color-landscape/blob/main/notebooks/autoencoder-grayscale-to-color-landscape.ipynb)
[![View on HuggingFace](https://img.shields.io/badge/View%20on-HuggingFace-181717?logo=huggingface)](https://huggingface.co/danhtran2mind/autoencoder-grayscale2color-landscape/blob/main/notebooks/autoencoder-grayscale-to-color-landscape.ipynb)

## Dataset
Details about the dataset are available in the [README Dataset](./dataset/README.md). 📂

## From Scratch Model
Custom-built autoencoder with a spatial attention mechanism, trained **FROM SCRATCH** to predict a*b* color channels from grayscale (L*) inputs. 🧩

## Demonstration
Experience the brilliance of our cutting-edge technology! Transform grayscale landscapes into vibrant colors with our interactive demo.

[![HuggingFace Space](https://img.shields.io/badge/%F0%9F%A4%97-HuggingFace%20Space-blue)](https://huggingface.co/spaces/danhtran2mind/autoencoder-grayscale2color-landscape)

![App Interface](./examples/gradio_app.png)

## Installation

### Step 1: Clone the Repository
```bash
git clone https://huggingface.co/danhtran2mind/autoencoder-grayscale2color-landscape
cd ./autoencoder-grayscale2color-landscape
git lfs pull
```

### Step 2: Install Dependencies
```bash
pip install -r requirements.txt
```

## Usage

Follow these steps to colorize images programmatically using Python.

### 1. Import Required Libraries
Install and import the necessary libraries for image processing and model inference.

```python
from PIL import Image
import os
import numpy as np
import tensorflow as tf
import requests
import matplotlib.pyplot as plt
from skimage.color import lab2rgb
from models.auto_encoder_gray2color import SpatialAttention
```

### 2. Load the Pre-trained Model
Download and load the autoencoder model from a remote source if it’s not already available locally.

```python
load_model_path = "./ckpts/best_model.h5"
os.makedirs(os.path.dirname(load_model_path), exist_ok=True)

print(f"Loading model from {load_model_path}...")
loaded_autoencoder = tf.keras.models.load_model(
    load_model_path, custom_objects={"SpatialAttention": SpatialAttention}
)
print("Model loaded successfully.")
```

### 3. Define Image Processing Functions
These functions handle image preprocessing, colorization, and visualization.

```python
def process_image(input_img):
    """Convert a grayscale image to color using the autoencoder."""
    # Store original dimensions
    original_width, original_height = input_img.size
    
    # Preprocess: Convert to grayscale, resize, and normalize
    img = input_img.convert("L").resize((512, 512))
    img_array = tf.keras.preprocessing.image.img_to_array(img) / 255.0
    img_array = img_array[None, ..., 0:1]  # Add batch dimension

    # Predict color channels
    output_array = loaded_autoencoder.predict(img_array)
    
    # Reconstruct LAB image
    L_channel = img_array[0, :, :, 0] * 100.0  # Scale L channel
    ab_channels = output_array[0] * 128.0      # Scale ab channels
    lab_image = np.stack([L_channel, ab_channels[:, :, 0], ab_channels[:, :, 1]], axis=-1)
    
    # Convert to RGB and clip values
    rgb_array = lab2rgb(lab_image)
    rgb_array = np.clip(rgb_array, 0, 1) * 255.0
    
    # Create and resize output image
    rgb_image = Image.fromarray(rgb_array.astype(np.uint8), mode="RGB")
    return rgb_image.resize((original_width, original_height), Image.Resampling.LANCZOS)

def process_and_save_image(image_path):
    """Process an image and save the colorized result."""
    input_img = Image.open(image_path)
    output_img = process_image(input_img)
    output_img.save("output.jpg")
    return input_img, output_img

def plot_images(input_img, output_img):
    """Display input and output images side by side."""
    plt.figure(figsize=(17, 8), dpi=300)
    
    # Plot input grayscale image
    plt.subplot(1, 2, 1)
    plt.imshow(input_img, cmap="gray")
    plt.title("Input Grayscale Image")
    plt.axis("off")
    
    # Plot output colorized image
    plt.subplot(1, 2, 2)
    plt.imshow(output_img)
    plt.title("Colorized Output Image")
    plt.axis("off")
    
    # Save and display the plot
    plt.savefig("output.jpg", dpi=300, bbox_inches="tight")
    plt.show()
```

### 4. Perform Inference
Run the colorization process on a sample image.

```python
# Set image dimensions and path
WIDTH, HEIGHT = 512, 512
image_path = "<path_to_input_image.jpg>"  # Replace with your image path

# Process and visualize the image
input_img, output_img = process_and_save_image(image_path)
plot_images(input_img, output_img)
```

### 5. Example Output
The output will be a side-by-side comparison of the input grayscale image and the colorized result, saved as `output.jpg`. For a sample result, see the example below:
![Output Image](./examples/model_output.png)

## Training Hyperparameters
- **Resolution**: 512x512 pixels
- **Color Space**: L*a*b*
- **Custom Layer**: SpatialAttention
- **Model File**: `best_model.h5`
- **Epochs**: 100

## Callbacks
- **Early Stopping**: Monitors `val_loss`, patience of 20 epochs, restores best weights.
- **ReduceLROnPlateau**: Monitors `val_loss`, reduces learning rate by 50% after 5 epochs, minimum learning rate of 1e-6.
- **BackupAndRestore**: Saves checkpoints to `./ckpts/backup`.

## Metrics
- **PSNR (Validation)**: 21.70 📈

## Environment
- Python 3.11.11
- Libraies
    ```
    numpy==1.26.4
    tensorflow==2.18.0
    opencv-python==4.11.0.86
    scikit-image==0.25.2
    matplotlib==3.7.2
    scikit-image==0.25.2
    ```

## Contact
For questions or issues, reach out via the [HuggingFace Community](https://huggingface.co/danhtran2mind/autoencoder-grayscale2color-landscape/discussions) tab. 🚀