Combine 3 separate numpy arrays to an RGB image in Python

Question

So I have a set of data which I am able to convert to form separate numpy arrays of R, G, B bands. Now I need to combine them to form an RGB image.

I tried 'Image' to do the job but it requires 'mode' to be attributed.

I tried to do a trick. I would use Image.fromarray() to take the array to image but it attains 'F' mode by default when Image.merge requires 'L' mode images to merge. If I would declare the attribute of array in fromarray() to 'L' at first place, all the R G B images become distorted.

But, if I save the images and then open them and then merge, it works fine. Image reads the image with 'L' mode.

Now I have two issues.

First, I dont think it is an elegant way of doing the work. So if anyone knows the better way of doing it, please tell

Secondly, Image.SAVE is not working properly. Following are the errors I face:

In [7]: Image.SAVE(imagefile, 'JPEG') ----------------------------------------------------------------------------------  TypeError                                 Traceback (most recent call last)  /media/New Volume/Documents/My own works/ISAC/SAMPLES/<ipython console> in <module>()  TypeError: 'dict' object is not callable 

Please suggest solutions.

And please mind that the image is around 4000x4000 size array.

Answer 1

rgb = np.dstack((r,g,b))  # stacks 3 h x w arrays -> h x w x 3 

To also convert floats 0 .. 1 to uint8 s,

rgb_uint8 = (np.dstack((r,g,b)) * 255.999) .astype(np.uint8)  # right, Janna, not 256 

Answer 2

I don't really understand your question but here is an example of something similar I've done recently that seems like it might help:

# r, g, and b are 512x512 float arrays with values >= 0 and < 1. from PIL import Image import numpy as np rgbArray = np.zeros((512,512,3), 'uint8') rgbArray[..., 0] = r*256 rgbArray[..., 1] = g*256 rgbArray[..., 2] = b*256 img = Image.fromarray(rgbArray) img.save('myimg.jpeg') 

I hope that helps