[FIXED] How do I type-hint OpenCV images in Python?

Issue

I get that in Python OpenCV images are numpy arrays, that correspond to cv::Mat in c++.

This question is about what type-hint to put into python functions to properly restrict for OpenCV images (maybe even for a specific kind of OpenCV image).

What I do now is:

import numpy as np
import cv2

Mat = np.ndarray

def my_fun(image: Mat):
    cv2.imshow('display', image)
    cv2.waitKey()

Is there any better way to add typing information for OpenCV images in python?

Solution

You can specify it as numpy.typing.NDArray with an entry type. For example,

import numpy as np

Mat = np.typing.NDArray[np.uint8]

def my_fun(img: Mat):
    pass

Answered By - user1635327