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?

5 Answers

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.

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

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() 

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() 

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()