Connected component labelling in Python

ccl.py

import numpy as np

# Time complexity: O(n), where n is the number of pixels in image
# Space complexity: O(n)
def label_connected_components(image: np.uint8) -> np.int:
    nrow = image.shape[0]
    ncol = image.shape[1]
    component_map = np.full((nrow, ncol), -1, dtype=np.int)
    current_comp_id = 1
    for r in range(nrow):
        for c in range(ncol):
            labeled_any_pixel = False
            queue.append((r, c))
            while len(queue) > 0:
                i, j = queue.popleft()
                
                if component_map[i, j] != -1: # already visited
                    continue

                if image[i, j] == 0: # zero pixels stay 0
                    component_map[i, j] = 0
                    continue

                labeled_any_pixel = True
                component_map[i, j] = current_comp_id
                
                # add neigbors
                if j > 0: 
                    queue.append((i, j-1)) # left
                if j < ncol - 1: 
                    queue.append((i, j+1)) # right
                if i > 0: 
                    queue.append((i-1, j)) # top
                if i < nrow - 1: 
                    queue.append((i+1, j)) # bottom
                
            if labeled_any_pixel:
                current_comp_id += 1
                
    return component_map, current_comp_id - 1