从图像中复制黑色像素并粘贴到具有偏移的同一图像中

Question

I've been trying to get some masking to work in my pictures, but I guess there has to be an easier way to do this:

a) I have an BW picture (photo) showing numbers from a display, "test.png" ( 1000x300 px)

b) I want to copy (only) the black pixels and paste them in the same image

c) When pasting, I want the paste to be offset by its "original" place by 20px (both x/y)

I try running the code below but get an error:

import cv2
test = Image.open('test.png')
np = Image.new('1', (1000, 300), 255)
mask = np.bitwise_and(test, np.roll(test, 20, (0,1)))
mask.save('mask.png')

I get AttributeError: 'Image' object has no attribute 'bitwise_and'

Answer 1

If image is logical (0/1) then:

res=np.bitwise_and(image, np.roll(image, 20, (0,1)))

Answer 2

You can do it like this:

from PIL import Image
import numpy as np

# Load image and make Numpy array
im = Image.open('image.png').convert('L')
na = np.array(im)

# Get x,y coordinates of black pixels
Y, X = np.where(na==0)

# Make pixels 30 across and 30 down from them black
na[Y+30, X+30] = 0

# Convert back to PIL Image and save
Image.fromarray(na).save('result.png')