CODEWITHSUNDEEP
pythonimagematplotlibgrayscale
luw
luw

Reputation: 217

How to plot a gray image and save it?

I am using matplotlib to plot function graphs, say, a sine function:

t = np.arange(0., 5., 0.2)
plt.plot(t, np.sin(t))

but it has 3 channels. How should I make a gray image (with only one channel) and save it as a numpy array with shape height * width * 1. Thank you!

Upvotes: 0

Views: 495

Answers (1)

spiridon_the_sun_rotator
spiridon_the_sun_rotator

Reputation: 1054

With the use of skimage library there is possible pipeline (it is still rather heavyweight, but now the quality of the image would be much better).

#import the required libraries and functions
import os
from skimage.io import imread
from skimage.color import rgb2gray, rgba2rgb

#create an image
x = np.linspace(0, 2 * np.pi, 100)
y = np.sin(x)
plt.plot(x, y)

#save and image as a .png picture and then load 
plt.savefig('img.png')
img = imread('img.png')
#we do not need the colored picture, so remove it
os.remove('img.png')

#the loaded picture is initially rgba, convert it to the grayscale image
img = rgb2gray(rgba2rgb(img))
#if you want a flat array saved as binary, ravel() it and use np.save
np.save('test.npy', img.ravel())

Upvotes: 1

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