Display multiple images in one IPython Notebook ce

Question

If I have multiple images (loaded as NumPy arrays) how can I display the in one IPython Notebook cell?

I know that I can use plt.imshow(ima) to display one image… but I want to show more than one at a time.

I have tried:

 for ima in images:
     display(Image(ima))

But I just get a broken image link:

Answer 1

from matplotlib.pyplot import figure, imshow, axis
from matplotlib.image import imread

mypath='.'
hSize = 5
wSize = 5
col = 4

def showImagesMatrix(list_of_files, col=10):
    fig = figure( figsize=(wSize, hSize))
    number_of_files = len(list_of_files)
    row = number_of_files/col
    if (number_of_files%col != 0):
        row += 1
    for i in range(number_of_files):
        a=fig.add_subplot(row,col,i+1)
        image = imread(mypath+'/'+list_of_files[i])
        imshow(image,cmap='Greys_r')
        axis('off')

showImagesMatrix(listOfImages,col)

based on @Michael answer

Answer 2

Somehow related to this question (and since I was directed to this answer when I was trying to solve it), I was able to solve a similar problem by simply typing the full file-path when calling Image(). In my case, I had to choose a random image from different folder paths stored in a list your_folder and display them.

import random, os 
for i in range(len(your_folder)):
   ra1 = "../"+your_folder[i]+"/"+random.choice(os.listdir(your_folder[i]))
   image = Image(ra1)
   display(image)

Answer 3

You can display multiple images in one IPython Notebook cell by using display and HTML functions. You need to create the set of html img tags as a string as follows

from IPython.display import Image, HTML, display
from glob import glob
imagesList=''.join( ["<img style='width: 120px; margin: 0px; float: left; border: 1px solid black;' src='%s' />" % str(s) 
                 for s in sorted(glob('yourimage*.png')) ])
display(HTML(imagesList))

See a example of use from http://nbviewer.ipython.org/github/PBrockmann/Dodecahedron

You may need to refresh your browser (shift + load) to see new images if they have been changed from a previous cell.

Answer 4

Short answer:

call plt.figure() to create new figures if you want more than one in a cell:

for ima in images:
    plt.figure()
    plt.imshow(ima)

But to clarify the confusion with Image:

IPython.display.Image is for displaying Image files, not array data. If you want to display numpy arrays with Image, you have to convert them to a file-format first (easiest with PIL):

from io import BytesIO
import PIL
from IPython.display import display, Image

def display_img_array(ima):
    im = PIL.Image.fromarray(ima)
    bio = BytesIO()
    im.save(bio, format='png')
    display(Image(bio.getvalue(), format='png'))

for ima in images:
    display_img_array(ima)

A notebook illustrating both approaches.

Answer 5

If you don't mind an additional dependency here is a two liner using scikit-image:

from skimage.util import montage
plt.imshow(montage(np.array(images), multichannel=True))

Set multichannel=True for color images and multichannel=False for grayscale images.

Answer 6

based on @ChaosPredictor answer

from matplotlib.pyplot import figure, imshow, axis
from matplotlib.image import imread

def showImagesMatrix(list_of_files, col=10, wSize=5, hSize=5, mypath='.'):
    fig = figure(figsize=(wSize, hSize))
    number_of_files = len(list_of_files)
    row = number_of_files / col
    if (number_of_files % col != 0):
        row += 1
    for i in range(number_of_files):
        a=fig.add_subplot(row, col, i + 1)
        image = imread(mypath + '/' + list_of_files[i])
        imshow(image, cmap='Greys_r')
        axis('off')

then

from pathlib import Path
p = Path('.')
num_images = 30
list_of_image_paths = [str(x) for x in list(p.glob('../input/train/images/*'))[:num_images]]

showImagesMatrix(list_of_image_paths)

# or with named args
showImagesMatrix(list_of_image_paths, wSize=20, hSize=10, col=5)