比较图像 Python PIL

Question

How can I compare two images? I found Python's PIL library, but I do not really understand how it works.

Answer 1

To check does jpg files are exactly the same use pillow library:

from PIL import Image
from PIL import ImageChops

image_one = Image.open(path_one)
image_two = Image.open(path_two)

diff = ImageChops.difference(image_one, image_two)

if diff.getbbox():
    print("images are different")
else:
    print("images are the same")

Answer 2

based on Victor Ilyenko's answer, I needed to convert the images to RGB as PIL fails silently when the .png you're trying to compare contains a alpha channel.

image_one = Image.open(path_one).convert('RGB')
image_two = Image.open(path_two).convert('RGB')

Answer 3

It appears that Viktor's implementation can fail when the images are different sizes.

This version also compares alpha values. Visually identical pixels are (I think) treated as identical, such as (0, 0, 0, 0) and (0, 255, 0, 0).

from PIL import ImageChops

def are_images_equal(img1, img2):
    equal_size = img1.height == img2.height and img1.width == img2.width

    if img1.mode == img2.mode == "RGBA":
        img1_alphas = [pixel[3] for pixel in img1.getdata()]
        img2_alphas = [pixel[3] for pixel in img2.getdata()]
        equal_alphas = img1_alphas == img2_alphas
    else:
        equal_alphas = True

    equal_content = not ImageChops.difference(
        img1.convert("RGB"), img2.convert("RGB")
    ).getbbox()

    return equal_size and equal_alphas and equal_content

Answer 4

Another implementation of Viktor 's answer using Pillow:

from PIL import Image

im1 = Image.open('image1.jpg')
im2 = Image.open('image2.jpg')

if list(im1.getdata()) == list(im2.getdata()):
    print("Identical")
else:
    print ("Different")

Answer 5

That did work for me, you just have to set the quantity of different pixels you accept, in my case 100, as the image diference was a complete black image but still had 25 diferent pixels. I tested other completelly diffferent images and they had diferrent pixels by thousands:

from PIL import ImageChops
if len(set(ImageChops.difference(img1, img2).getdata())) > 100:
    print("Both images are diffent!")