Python read binary file of unsigned 16 bit integers

Question

I must read a binary file in Python, and store its content in an array. The information I have on this file is that

filename.bin is of size 560x576 (height x width) with 16 b/p, i.e., unsigned 16-bit integer for each pixel

This is what I have been able to come up with so far:

import struct
import numpy as np
fileName = "filename.bin"

with open(fileName, mode='rb') as file: 
    fileContent = file.read()



a = struct.unpack("I" * ((len(fileContent)) // 4), fileContent)

a = np.reshape(a, (560,576))

However I get the error

cannot reshape array of size 161280 into shape (560,576)

161280 is exactly half of 560 x 576 = 322560. I would like to understand what I am doing wrong and how to read the binary file and reshape in the required form.

Deepstop · Accepted Answer · 2019-06-16 12:23:22Z

3

You are using 'I' for the format which is 32 bit unsigned instead of 'H' which is 16 bit unsigned.

Do this

a = struct.unpack("H" * ((len(fileContent)) // 2), fileContent)

answered Jun 16, 2019 at 12:23

Deepstop

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2 Comments

johnhenry Over a year ago

thanks for your answer. Just to see if I understood: if instead my file was 560 x 576, 32-bit signed integer per pixel, what I would have to use is `struct.unpack("i" * ((len(fileContent)) // 4), fileContent)' , right?

Deepstop Over a year ago

Yes, but with a capital I for unsigned. Small i is signed.

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