CODEWITHSUNDEEP
pythonopencvmatplotlib
user1245262
user1245262

Reputation: 7505

How can one display an image using cv2 in Python

I've been working with code to display frames from a movie. The bare bones of the code is as follows:

import cv2
import matplotlib.pyplot as plt

# Read single frame avi
cap = cv2.VideoCapture('singleFrame.avi')
rval, frame = cap.read()

# Attempt to display using cv2 (doesn't work)
cv2.namedWindow("Input")
cv2.imshow("Input", frame)

#Display image using matplotlib (Works)
b,g,r = cv2.split(frame)
frame_rgb = cv2.merge((r,g,b))
plt.imshow(frame_rgb)
plt.title('Matplotlib') #Give this plot a title, 
                        #so I know it's from matplotlib and not cv2
plt.show()

Because I can display the image using matplotlib, I know that I'm successfully reading it in.

I don't understand why my creation of a window and attempt to show an image using cv2 doesn't work. No cv2 window ever appears. Oddly though, if I create a second cv2 window, the 'input' window appears, but it is only a blank/white window.

What am I missing here?

Upvotes: 75

Views: 296272

Answers (7)

Mans007
Mans007

Reputation: 13

When using Jupyter notebook, matplotlib may not display the image at its full scale.
I found that display in conjunction with PIL Image works better.

import cv2
from PIL import Image

img_bgr = cv2.imread("path/to/image")  # array in BGR format
img_rgb = cv2.cvtColor(img_bgr, cv2.COLOR_BGR2RGB)  # BGR -> RGB
img = Image.fromarray(img_rgb)  # convert to PIL image
display(img)

Upvotes: 0

Learner
Learner

Reputation: 11

If you are using Google Collab then use the following two lines:

from google.colab.patches import cv2_imshow

cv2_imshow(image)

Upvotes: 0

baktinanda
baktinanda

Reputation: 41

import cv2

image_path='C:/Users/bakti/PycharmProjects/pythonProject1/venv/resized_mejatv.jpg'

img=cv2.imread(image_path)

img_title="meja tv"

cv2.imshow(img_title,img)

cv2.waitKey(0)

cv2.destroyAllWindows()

Upvotes: 4

Hemanth Kollipara
Hemanth Kollipara

Reputation: 1141

While using Jupyter Notebook this one might come in handy

import cv2
import matplotlib.pyplot as plt

# reading image
image = cv2.imread("IMAGE_PATH")

# displaying image
plt.imshow(image)
plt.show()

Upvotes: 7

sungjun park
sungjun park

Reputation: 193

Since OpenCV reads images with BGR format, you'd convert it to RGB format before pass the image to pyplot

import cv2
import matplotlib.pyplot as plt

image = cv2.imread('YOUR_FILEPATH')
image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
plt.imshow(image)
plt.show()

Upvotes: 18

amruta patil
amruta patil

Reputation: 271

you can follow following code

import cv2
# read image 
image = cv2.imread('path to your image')
# show the image, provide window name first
cv2.imshow('image window', image)
# add wait key. window waits until user presses a key
cv2.waitKey(0)
# and finally destroy/close all open windows
cv2.destroyAllWindows()

I think your job is done then

Upvotes: 27

phev8
phev8

Reputation: 3773

As far as I can see, you are doing it almost good. There is one thing missing:

cv2.imshow('image',img)
cv2.waitKey(0)

So probably your window appears but is closed very very fast.

Upvotes: 133

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