CODEWITHSUNDEEP
python
loay
loay

Reputation: 19

How do I compare between two images in python?

My code is:

import cv2

from PIL import Image

import numpy as np

img=cv2.imread("IMG040.jpg")

img2=cv2.imread("IMG040.jpg")

p1 = np.array(img)

p2 = np.array(img2)

img3=img-img2

p3 = np.array(img3)

if p3==0 :
    print "the same"
else: 
    print"not the same"


but I have this problem
File "part2.py", line 10, in <module>
    if p3==0 :

Error message:

**ValueError:** The truth value of an array with more than one element is
ambiguous. Use a.any() or a.all()

Upvotes: 0

Views: 313

Answers (2)

YXD
YXD

Reputation: 32511

The expression

p3==0

Creates a boolean numpy array. The Python if statement does not know how to interpret this whole array as being true or false. That's what the error message means. You presumably want to know if all of the elements are zero and that is why the error message suggests you should use all().

To do this, you would end up changing the line to

if (p3==0).all():

However it is better to compare numpy arrays with the allclose method, which can account for numerical errors. So try replacing this

img3=img-img2

p3 = np.array(img3)

if p3==0 :
    print "the same"
else: 
    print"not the same"

with

if np.allclose(img, img2):
    print "the same"
else:
    print "not the same"

Upvotes: 1

froot93
froot93

Reputation: 86

You need to do the if statement like this:

if np.all(p3==0):
    print 'The same'
else:
    print 'Not the same'

Upvotes: 0

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