Imageio is a popular Python library for reading and writing a wide range of image data formats. It offers powerful functionality for manipulating and processing images, including palette handling.

In this blog post, we will explore how to perform palette processing using Imageio in Python. Specifically, we will cover the following topics:

1. Reading an image with a palette
2. Accessing and modifying the palette
3. Applying the modified palette to the image
4. Saving the image with the modified palette

1. Reading an image with a palette

To begin, let’s import the necessary libraries and load an image with a color palette using Imageio:

import imageio

# Load image with palette
image_path = 'path/to/image.png'
image = imageio.imread(image_path, format='PNG-PIL')

Note that we are specifying the format as ‘PNG-PIL’ when reading the image to ensure that the palette information is preserved.

2. Accessing and modifying the palette

Once we have loaded the image, we can access the palette associated with it. The palette is stored as an array of color values.

# Access the palette
palette = imageio.getpalette(image)

# Modify the palette
new_palette = [...]  # Replace with your own palette values
imageio.imwrite('path/to/new_palette.png', palette=new_palette)

Here, we use the getpalette() function to retrieve the current palette of the image. We can then modify the retrieved palette array to suit our requirements. Finally, we save the modified palette to a new image file using the imwrite() function and specifying the palette parameter.

3. Applying the modified palette to the image

After modifying the palette, we need to apply it to the image to see the changes. Imageio provides a convenient function called reconstruct_huffman() to achieve this.

# Apply modified palette to the image
imageio.core.imhint.reconstruct_huffman(image, palette)

The reconstruct_huffman() function takes the modified palette and applies it to the image. This step is necessary to ensure that the image is correctly displayed with the new color palette.

4. Saving the image with the modified palette

Finally, we can save the image with the modified palette using the imwrite() function. By specifying the palette parameter, Imageio will use the provided palette for saving the image.

# Save the image with the modified palette
new_image_path = 'path/to/new_image.png'
imageio.imwrite(new_image_path, image, format='PNG-PIL', palette=new_palette)

Remember to specify the format as ‘PNG-PIL’ and provide the modified palette as the palette parameter when saving the image.

That’s it! With these steps, you can easily perform palette processing on images using Imageio in Python. Whether you want to modify the existing palette or replace it entirely, Imageio provides the necessary tools and functions to accomplish these tasks efficiently.

Remember to refer to the official Imageio documentation for more detailed information and additional features offered by the library.

Happy coding!