Multiprocessing OpenCV in Python

Question

I have a simple Algorithm, I want to run it fast in parallel. The algo is.

while stream:
    img = read_image()
    pre_process_img = pre_process(img)
    text = ocr(pre_process_img)
    fine_text = post_process(text)

Now I want to explore what are the fastest options I can get using python for multiprocessing the algorithm.

Some of the code is as follows:

def pre_process_img(frame):
    return cv2.cvtColor(frame, cv2.COLOR_RGB2GRAY)

def ocr(frame):
    return pytesseractt.image_to_string(frame)

How can I run the given code in parallel/multiple threads/other options, especially the pre-process and ocr part?

I have tried JobLib, but it is for for-loops, and I wasn't sure how to implement it while loop in continuous frames.

I have been seeing people's code, but I am unable to reproduce it for my example.

Edit

We can definitely combine it in a pipeline.

while stream:
    img = read_image()
    results = pipeline(img)

Now I want to execute the pipeline for different frames in multiple processes.