How to read an image in Python OpenCV

Question

I am trying to read and display an image in Python OpenCV.

Executing the following code:

import cv2 import numpy as np import matplotlib.pyplot as plt  img = cv2.imread('dumb.jpg', cv2.IMREAD_GRAYSCALE)  cv2.imshow('image',img) cv2.waitKey(0) cv2.destroyAllWindows() 

Results in the following error:

cv2.error: C:\build\master_winpack-bindings-win64-vc14-static\opencv\modules\highgui\src\window.cpp:325: error: (-215) size.width>0 && size.height>0 in function cv::imshow

How to solve this?

NOTE: I have all the prerequisites needed to execute this (python 2.7, opencv 3.3 matplotlib, numpy)

Answer 1

If you are trying to display OpenCV image using matplotlib, use the code below.

import numpy as np import cv2 import matplotlib.pyplot as plt %matplotlib inline  # if you are running this code in Jupyter notebook  # reads image 'opencv-logo.png' as grayscale img = cv2.imread('/path_to_image/opencv-logo.png', 0)  plt.imshow(img, cmap='gray') 

Answer 2

there is a tutorial on http://docs.opencv.org/3.1.0/dc/d2e/tutorial_py_image_display.html

 import numpy as np  import cv2   # Load an color image in grayscale  img = cv2.imread('/path_to_image/messi5.jpg',0)   # show image   cv2.imshow('image',img)  cv2.waitKey(0)  cv2.destroyAllWindows() 

use an absolute path to the image then you have no path problems

https://en.wikipedia.org/wiki/Path_(computing)#Absolute_and_relative_paths

OpenCV Error: (-215)size.width>0 && size.height>0 in function imshow