Ipython notebook (jupyter),opencv (cv2) and plotting?

Question

Is there a way to use and plot with opencv2 with ipython notebook?

I am fairly new to python image analysis. I decided to go with the notebook work flow to make nice record as I process and it has been working out quite well using matplotlib/pylab to plot things.

An initial hurdle I had was how to plot things within the notebook. Easy, just use magic:

%matplotlib inline 

Later, I wanted to perform manipulations with interactive plots but plotting in a dedicated window would always freeze. Fine, I learnt again that you need to use magic. Instead of just importing the modules:

%pylab 

Now I have moved onto working with opencv. I am now back to the same problem, where I either want to plot inline or use dedicated, interactive windows depending on the task at hand. Is there similar magic to use? Is there another way to get things working? Or am I stuck and need to just go back to running a program from IDLE?

As a side note: I know that opencv has installed correctly. Firstly, because I got no errors either installing or importing the cv2 module. Secondly, because I can read in images with cv2 and then plot them with something else.

Answer 1

This is my empty template:

import cv2 import matplotlib.pyplot as plt import numpy as np import sys %matplotlib inline  im = cv2.imread('IMG_FILENAME',0) h,w = im.shape[:2] print(im.shape) plt.imshow(im,cmap='gray') plt.show() 

See online sample

Answer 2

For a Jupyter notebook running on Python 3.5 I had to modify this to:

import io import cv2 import numpy as np from IPython.display import clear_output, Image, display import PIL.Image  def showarray(a, fmt='jpeg'):     a = np.uint8(np.clip(a, 0, 255))     f = io.BytesIO()     PIL.Image.fromarray(a).save(f, fmt)     display(Image(data=f.getvalue()))