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\

Answer 1

Convert the numpy arrays to uint8 before passing them to Image.fromarray

Eg. if you have floats in the range [0..1]:

r = Image.fromarray(numpy.uint8(r_array*255.999))

Answer 2

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 3

Your distortion i believe is caused by the way you are splitting your original image into its individual bands and then resizing it again before putting it into merge;

`
image=Image.open("your image")

print(image.size) #size is inverted i.e columns first rows second eg: 500,250

#convert to array
li_r=list(image.getdata(band=0))
arr_r=np.array(li_r,dtype="uint8")
li_g=list(image.getdata(band=1))
arr_g=np.array(li_g,dtype="uint8")
li_b=list(image.getdata(band=2))
arr_b=np.array(li_b,dtype="uint8")

# reshape 
reshaper=arr_r.reshape(250,500) #size flipped so it reshapes correctly
reshapeb=arr_b.reshape(250,500)
reshapeg=arr_g.reshape(250,500)

imr=Image.fromarray(reshaper,mode=None) # mode I
imb=Image.fromarray(reshapeb,mode=None)
img=Image.fromarray(reshapeg,mode=None)

#merge
merged=Image.merge("RGB",(imr,img,imb))
merged.show()
`

this works well !

Answer 4

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

Answer 5

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

This code doesnt create 3d array if you pass 3 channels. 2 channels remain.