Python matplotlib imshow always give me white no matter if i send array of 1s or 0s

Question

import matplotlib.pyplot as plt
import numpy as np
_im1 = np.array([
    [1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1]
]).astype(np.uint8)

_im2 = np.array([
    [0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0]
]).astype(np.uint8)


fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(8, 8))

ax1.set_title('1s')
ax1.imshow(_im1 , cmap='binary')

ax2.set_title('Os')
ax2.imshow(_im2, cmap='binary')

plt.tight_layout()
plt.subplots_adjust(top=1)
plt.show()
plt.clf()

I am getting both the images to be white color. I have tried using cmap='grey' then both show as black I was using this has reference : Getting black plots with plt.imshow after multiplying image array by a scalar

Kurtis Streutker · Accepted Answer · 2018-11-03T15:29:01.497

2

ax1.set_title('1s')
ax1.imshow(_im1, cmap='binary', vmin=0, vmax=1)

ax2.set_title('Os')
ax2.imshow(_im2, cmap='binary', vmin=0, vmax=1)

Edit: updated to satisfy comment. cmap='gray' with vmax/vmin works as well

edited Nov 03 '18 at 15:29

answered Nov 03 '18 at 14:39

Kurtis Streutker

1,157
10
13

This input you are generating is not like the input in the question. If you had the input in the question, how would you generate the correct plot? – Rob Bricheno Nov 03 '18 at 14:50
i tried cmap='gray' , did not work for me. however, , vmin=0, vmax=1 works – Manpreet Singh Bhinder Nov 03 '18 at 15:21
oh sorry, I meant ```cmap='gray'``` with the vmax/vmin – Kurtis Streutker Nov 03 '18 at 15:28

Python matplotlib imshow always give me white no matter if i send array of 1s or 0s

1 Answers1