Problems Converting Images from 8-bit to 10-bit

Question

I am trying to convert 8 bit images to 10 bit. I thought it would be as easy as changing the bin values. I've tried to pillow and cv-python:

from PIL import Image
from numpy import asarray
import cv2

path = 'path/to/image'
img = Image.open(path)
data = asarray(img)

newdata = (data/255)*1023 #2^10 is 1024
img2 = Image.fromarray(newdata) #this fails

cv2.imwrite('path/newimage.png, newdata)

While cv2.imwrite successfully writes the new file, it is still encoded as an 8bit image even though bin goes up to 1023.

$ file newimage.png
newimage.png: PNG Image data, 640 x 480, 8-bit/color RGB, non-interlaced

Is there another way in either python or linux that can convert 8-bit to 10-bit?

Answer 1

Lots of things going wrong here.

1. You are mixing OpenCV ( cv2.imwrite ) with PIL ( Image.open ) for no good reason. Don't do that, you will confuse yourself as they use different RGB/BGR orderings and conventions,

2. You are trying to store 10-bit numbers in 8-bit vectors,

3. You are trying to hold 3 16-bit RGB pixels in a PIL Image which will not work as RGB images must be 8-bit in PIL.

---

I would suggest:

import cv2
import numpy as np

# Load image
im = cv2.imread(IMAGE, cv2.IMREAD_COLOR)

res = im.astype(np.uint16) * 4
cv2.imwrite('result.png', res)

Answer 2

I found a solution using pgmagick wrapper for python

import pgmagick as pgm

imagePath = 'path/to/image.png'
saveDir = '/path/to/save'

img = pgm.Image(imagePath)
img.depth(10) #sets to 10 bit

save_path = os.path.join(saveDir,'.'.join([filename,'dpx']))
img.write(save_path)