How to control image format in matplotlib.pyplot.imsave?

Backend
1

I’m using matplotlib.pyplot in Spyder and need to save numpy arrays as images. The imsave() function docs mention that the available formats depend on the backend. What exactly does the backend do? I can create .tiff files, but I’m looking to generate 8-bit tiffs instead of RGB ones. How can I adjust the settings to change the format?

import numpy as np
import matplotlib.pyplot as plt

data = np.random.rand(100, 100)
plt.imsave('my_image.tiff', data)

I’ve tried this approach, but it only produces RGB tiffs. Is there a way to specify the bit depth or color mode when saving the image? Any guidance would be appreciated!

2

hey there! i’ve run into this before. the backend is like the engine that handles the graphics stuff. for 8-bit tiffs, try using PIL instead of matplotlib. it gives you more control over image formats. something like:

from PIL import Image
Image.fromarray((data * 255).astype('uint8')).save('my_image.tiff')

hope that helps!

3

The backend in matplotlib refers to the underlying library that handles the actual rendering and output of graphics. For your specific requirement of generating 8-bit TIFF files, you might want to consider using the Pillow library (PIL) as it offers more granular control over image formats and bit depths.

Here’s an approach you could try:

import numpy as np
from PIL import Image

data = np.random.rand(100, 100)
scaled_data = (data * 255).astype(np.uint8)
image = Image.fromarray(scaled_data, mode='L')
image.save('my_image.tiff', format='TIFF', compression='tiff_deflate')

This method allows you to create an 8-bit grayscale TIFF. The ‘L’ mode specifies a single-channel (grayscale) image, and the compression option helps reduce file size. Adjust the parameters as needed for your specific use case.