Convert C# byte array to numpy array in Python .Net

Question

I try to use a .NET Assembly in a python application using Python.NET. The C# code captures an image, that i want to use with python. Let's say I have the following C# method:

public static byte[] Return_Image_As_Byte_Array()
    {
        Image image = Image.FromFile("C:\path\to\an\image");
        ImageConverter imageConverter = new ImageConverter();
        byte[] ByteArray = (byte[])imageConverter.ConvertTo(image, typeof(byte[]));
        return ByteArray;
    }

When I use Python.Net in python i do the following:

import clr
clr.AddReference('MyAssembly')
from MyAssembly import MyClass
print(MyClass.Return_Image_As_Byte())

This gives me the output:

<System.Byte[] at 0xb7ba20c080>

Is there a way to turn this image from C# into a native python type like numpy array?

this looks like resolved here: github.com/pythonnet/pythonnet/issues/174 — den.run.ai
– den.run.ai, Commented Sep 13, 2016 at 5:44
@dlammy if you need performance, take a look here: github.com/pythonnet/pythonnet/issues/514 — den.run.ai
– den.run.ai, Commented Oct 19, 2020 at 21:24
@denfromufa Yes in fact I've used robbmcleod solution and it's very fast. thanks — Jamal Alkelani
– Jamal Alkelani, Commented Oct 21, 2020 at 13:00

phispi · Accepted Answer · 2022-01-21 11:31:34Z

1

It's possible to convert C# Byte[] to Python bytes first and from that to numpy (Python 3.8):

from System import Byte, Array
import numpy as np

c_sharp_bytes = Array[Byte](b'Some bytes')  # <System.Byte[] object at 0x000001A33CC2A3D0>
python_bytes = bytes(c_sharp_bytes)
numpy_bytes = np.frombuffer(python_bytes, 'u1')  # b'Some bytes'
# numpy_bytes is now array([ 83, 111, 109, 101,  32,  98, 121, 116, 101, 115], dtype=uint8)

answered Jan 21, 2022 at 11:31

phispi

8898 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Andrew · Accepted Answer · 2021-09-06 19:10:47Z

0

If you are looking for Performance: I found that np.fromiter() (numpy) was 6 times faster than the provided answer in @dlammy url link above as response to the question. The used function was asNumpyArray() url: https://github.com/pythonnet/pythonnet/issues/514

Since there was such a distinction in times I thought only one timed run would suffice, instead of averaging the results. My Result: np.fromiter() : 67.914736s asNumpyArray(): 334.5198s

Solution Found here: https://stackoverflow.com/a/61077271/4084346

answered Sep 6, 2021 at 19:10

Andrew

1321 gold badge2 silver badges9 bronze badges

Collectives™ on Stack Overflow

Convert C# byte array to numpy array in Python .Net

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related