How to create a Numpy array with integer values? (current version doesn't work with getpixel)-CodePudding

I'm using PIL to get the red values from every pixel of a picture. However, I need all the values to be in numpy arrays, because as far as I know, that is the only way to plot a 3D graph with a colourmap. The problem is when I try to find the required red values using getpixel(), I get the following error:

Traceback (most recent call last):
  File "C:\Users\Elitebook\Desktop\PIL\Smoke\get_data_smoke.py", line 14, in <module>
    Z=im_rgb.getpixel((X,Y))[0]
  File "C:\Users\Elitebook\AppData\Roaming\Python\Python37\site-packages\PIL\Image.py", line 1436, in getpixel
    return self.im.getpixel(xy)
TypeError: an integer is required

So far, I have tried using x=x.astype(int) and dtype to get integer values, but none of them worked.

Here is my code:

from PIL import Image
import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import axes3d

im=Image.open("smoke.jpg")
im_rgb=im.convert("RGB")

w,h=im.size

x=np.arange(1,w 1,1)
y=np.arange(1,h 1,1)
X,Y=np.meshgrid(x,y)
Z=im_rgb.getpixel((X,Y))[0]

fig=plt.figure()
ax=fig.add_subplot(projection='3d')
ax.plot(X,Y,Z)
plt.show()

CodePudding user response：

If you want the image as a Numpy array, just use:

na = np.array(im_rgb)

CodePudding user response：

Your problem is that getpixel needs a sequence of integers. Your inputs X and Y were arrays. Therefore, you need some form of loop to extract the individual indexes:

x = np.arange(1,w 1,1)
y = np.arange(1,h 1,1)
X,Y = np.meshgrid(x,y)
Z = []
for i,j in zip(X,Y):
      for ii, jj in zip(i,j):
            Z.append(im_rgb.getpixel((int(ii),int(jj))))