Problem
I’ve made an array like this:
import numpy as np
data = np.zeros( (512,512,3), dtype=np.uint8)
data[256,256] = [255,0,0]
The goal is to make a single red dot appear in the center of a 512×512 image. (At least for now… I think I’ll be able to work out the rest.)
Asked by jlswint
Solution #1
The following should be sufficient:
from matplotlib import pyplot as plt
plt.imshow(data, interpolation='nearest')
plt.show()
Use this inline command before importing matplotlib if you’re using Jupyter notebook/lab:
%matplotlib inline
Installing ipyml pip is a more feature-rich option. Install ipympl and start using it.
%matplotlib widget
see an example.
Answered by Steve Tjoa
Solution #2
You could make (and display) an image with PIL:
from PIL import Image
import numpy as np
w, h = 512, 512
data = np.zeros((h, w, 3), dtype=np.uint8)
data[0:256, 0:256] = [255, 0, 0] # red patch in upper left
img = Image.fromarray(data, 'RGB')
img.save('my.png')
img.show()
Answered by unutbu
Solution #3
The shortest path is to utilize scipy, as shown here:
from scipy.misc import toimage
toimage(data).show()
This also necessitates the installation of PIL or Pillow.
A related approach, which similarly necessitates PIL or Pillow but may use a different viewer, is:
from scipy.misc import imshow
imshow(data)
Answered by Peter Hansen
Solution #4
There are easier answers, but this one will help you grasp how images are generated from a numpy array.
Load example
from sklearn.datasets import load_digits
digits = load_digits()
digits.images.shape #this will give you (1797, 8, 8). 1797 images, each 8 x 8 in size
One image is displayed in an array.
digits.images[0]
array([[ 0., 0., 5., 13., 9., 1., 0., 0.],
[ 0., 0., 13., 15., 10., 15., 5., 0.],
[ 0., 3., 15., 2., 0., 11., 8., 0.],
[ 0., 4., 12., 0., 0., 8., 8., 0.],
[ 0., 5., 8., 0., 0., 9., 8., 0.],
[ 0., 4., 11., 0., 1., 12., 7., 0.],
[ 0., 2., 14., 5., 10., 12., 0., 0.],
[ 0., 0., 6., 13., 10., 0., 0., 0.]])
To visualize 100 photos, create empty 10 x 10 subplots.
import matplotlib.pyplot as plt
fig, axes = plt.subplots(10,10, figsize=(8,8))
Plotting 100 images
for i,ax in enumerate(axes.flat):
ax.imshow(digits.images[i])
Result:
What is the purpose of axes.flat? It generates a numpy enumerator that can be used to iterate through axes and draw things on them. Example:
import numpy as np
x = np.arange(6).reshape(2,3)
x.flat
for item in (x.flat):
print (item, end=' ')
Answered by Hrvoje
Solution #5
import numpy as np
from keras.preprocessing.image import array_to_img
img = np.zeros([525,525,3], np.uint8)
b=array_to_img(img)
b
Answered by Sivasai
Post is based on https://stackoverflow.com/questions/2659312/how-do-i-convert-a-numpy-array-to-and-display-an-image