How To Use Opencv Copyto() Function?

I have read through the documentation for copyTo() but am still confused on how this function would be applied to the following code. This anwer states that we can use the copyTo f

Solution 1:

Sorry that I kind of misled you there. Although it works nicely in C++, I cannot find the binding in Python. You can, however, use numpy.copyto function.

Here is a small demo that shows that both method (bitwise_not and copyto) produce identical result.

import cv2
import numpy as np

# Create two images
im1 = np.zeros((100, 100, 3), np.uint8)
im1[:] = (255, 0, 0)
im2 = np.zeros((100, 100, 3), np.uint8)
im2[:] = (0, 255, 0)# Generate a random mask
ran = np.random.randint(0, 2, (100, 100), np.uint8)

# List of images and masks
images = [im1, im2]
mask = [ran, 1-ran]

not_output = np.zeros((100, 100, 3), np.uint8)
copy_output = np.zeros((100, 100, 3), np.uint8)

for i in range(0, len(images)):
    # Using the 'NOT' way
    not_output = cv2.bitwise_not(images[i], not_output, mask=mask[i])
    # Using the copyto way
    np.copyto(copy_output, images[i], where=mask[i][:, :, None].astype(bool))

cv2.imwrite('not.png', 255 - not_output)
cv2.imwrite('copy.png', copy_output)

Note that an extra dimension was padded to the mask array so that it can be broadcasted.