import matplotlib.pyplot as plt
import numpy as np
 
def samplemat(dims):
 """Make a matrix with all zeros and increasing elements on the diagonal"""
 aa = np.zeros(dims)
 for i in range(min(dims)):
  aa[i, i] = i
 return aa
 
# Display matrix
plt.matshow(samplemat((15, 15)))
 
plt.show()

import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm
from mpl_toolkits import mplot3d
 
cap = cv.VideoCapture(0)
cpframe = None
while True:
 ret, frame = cap.read()
 cv.imshow("video", frame)
 if cv.waitKey(1) & 0xFF ==ord('q'):
  cpframe = frame
  break
 
img_gray = cv.cvtColor(cpframe, cv.COLOR_RGB2GRAY)
 
Y = np.arange(0, np.shape(img_gray)[0], 1)
X = np.arange(0, np.shape(img_gray)[1], 1)
X, Y = np.meshgrid(X, Y)
fig = plt.figure()
ax = plt.axes(projection="3d")
ax.plot_surface(X, Y, img_gray, cmap=cm.gist_rainbow)
plt.show()