Python: How to change a "penny" image color (copper) to different gray levels?

Question

Python: How to change a "penny" image color (copper) to different gray levels? Example given in image

import numpy as np 
import scipy.io as sio 
import matplotlib.pyplot as plt 
import matplotlib.image as mpimg 

plt.clf()

p = plt.imread ('penny.jpg') 
plt.imshow(p) 

penny = p.copy()

Please provide more details about what you want to achieve, what you have tried. including everything in a linked image is not helpful to people trying to help you. — LmW., Sep 18 '18 at 01:20
plt.clf() import numpy as np import scipy.io as sio import matplotlib.pyplot as plt import matplotlib.image as mpimg p = plt.imread ('penny.jpg') plt.imshow(p) penny = p.copy() Then what should I do to change the gray levels of a regular penny color? — student, Sep 18 '18 at 01:21
edit your post and add code in code block instead of add them in comment — Circle Hsiao, Sep 18 '18 at 02:12

score 0 · Answer 1 · answered Sep 18 '18 at 02:29

The conversion to grayscale code comes from https://stackoverflow.com/a/12201744/1092820

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.image as mpimg

# Import the image
p = plt.imread('penny.png')

# Convert to grayscale
gray = np.dot(p[...,:3],[0.299, 0.587, 0.114])

# Round gray to nearest 1/n, where n is how many grays:
grayCount = 4
roundedGray = np.floor(gray * float(grayCount)) / float(grayCount)

# Display using matplotlib's copper color mapping
plt.imshow(roundedGray, cmap=plt.get_cmap('copper'))

plt.show()

Python: How to change a "penny" image color (copper) to different gray levels?

1 Answers1