From JPG to b64encode to cv2.imread()

Question

For a program I am writing, I am transferring an image from one computer - using base64.b64encode(f.read(image)) - and trying to read it in the receiving script without savi

Answer 1

From the OpenCV documentation we can see that:

imread : Loads an image from a file.

imdecode : Reads an image from a buffer in memory.

Seem a better way to do what you want.

Answer 2

You can get a numpy array from you decoded data using:

import numpy as np
...
img = base64.b64decode(msg.payload)
npimg = np.fromstring(img, dtype=np.uint8)

Then you need imdecode to read the image from a buffer in memory. imread is meant to load an image from a file.

So:

import numpy as np
...
def on_message(client, userdata, msg): # msg.payload is incoming data
    img = base64.b64decode(msg.payload); 
    npimg = np.fromstring(img, dtype=np.uint8); 
    source = cv2.imdecode(npimg, 1)