Opencv Python open dng format

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I can't figure out how to open a dng file in opencv. The file was created when using the pro options of the Samsung Galaxy S7. The images that are created when using those options are a dng file as well as a jpg of size 3024 x 4032 (I believe that is the dimensions of the dng file as well).

I tried using the answer from here (except with 3 colors instead of grayscale) like so:

import numpy as np
fd = open("image.dng", 'rb')
rows = 4032
cols = 3024
colors = 3
f = np.fromfile(fd, dtype=np.uint8,count=rows*cols*colors)
im = f.reshape((rows, cols,colors)) #notice row, column format

However, i got the following error:

 cannot reshape array of size 24411648 into shape (4032,3024,3)

Any help would be appreciated

2017-12-25 14:39
by John


As far as i know it is possible that DNG files can be compressed (even though it is lossless format), so you will need to decode your dng image first. is capable of doing that.

There is python wrapper for that library (

import rawpy
import imageio

path = 'image.dng'
with rawpy.imread(path) as raw:
    rgb = raw.postprocess()
2017-12-25 15:33
by Dmitrii Z.