import cv2
import numpy as np
from timeit import default_timer as timer

src = cv2.imread('test.png', cv2.IMREAD_UNCHANGED)

def test_old(src):
    image = src.copy()
    rows, cols, channels = image.shape
    for row in range(rows):
        for col in range(cols):
            pixel = image[row, col]
            for channel in range(channels):
                if pixel[channel] >= 245:
                    pixel[channel] = 255
                    if channel == 3:
                        pixel[channel] = 0
                else:
                    break
    return image

def test_new(src):
    image = src.copy()
    mask = image >= 245

    mask_0 = mask[:,:,0]
    mask_1 = mask_0 & mask[:,:,1]
    mask_2 = mask_1 & mask[:,:,2]
    mask_3 = mask_2 & mask[:,:,3]

    image[mask_0,0] = 255
    image[mask_1,1] = 255
    image[mask_2,2] = 255
    image[mask_3,3] = 0

    return image

start = timer()
image1 = test_old(src)
mid = timer()
image2 = test_new(src)
end = timer()


t1 = (mid - start)
t2 = (end - mid)
match = (image1 == image2).all()

print((t1, t2, t1/t2, match))