Machine Learning for OpenCV 4 - Second Edition

Visualizing the true-color palette

By performing the following steps, you will be able to visualize the true-color palette of a color image:

1. Let's have a look at a particular image:

In [1]: import cv2...     import numpy as np...     lena = cv2.imread('data/lena.jpg', cv2.IMREAD_COLOR)

2. By now, we know how to start Matplotlib in our sleep:

In [2]: import matplotlib.pyplot as plt...     %matplotlib inline...     plt.style.use('ggplot')

3. However, this time, we want to disable the grid lines that the ggplot option typically displays over images:

In [3]: plt.rc('axes', **{'grid': False})

4. Then, we can visualize Lena with the following command (don't forget to switch the BGR ordering of the color channels to RGB):

In [4]: plt.imshow(cv2.cvtColor(lena, cv2.COLOR_BGR2RGB)) ...