Colour_Selection.py

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

# Read in the image and print out some stats
image = mpimg.imread('Resource/test.jpg')
print('This image is: ',type(image), 
         'with dimensions:', image.shape)

# Grab the x and y size and make a copy of the image
ysize = image.shape[0]
xsize = image.shape[1]
# Note: always make a copy rather than simply using "="
color_select = np.copy(image)

# Define our color selection criteria
# Note: if you run this code, you'll find these are not sensible values
# #c8c8c8
red_threshold = 200
green_threshold = 200
blue_threshold = 200
rgb_threshold = [red_threshold, green_threshold, blue_threshold]

#  Identify pixels below the threshold
#  All colour converted black colour except white colour through thresholds function
#  All pixels that meet my color criterion (those above the threshold) will be retained,
# and those that do not (below the threshold) will be blacked out.
thresholds = (image[:,:,0] < rgb_threshold[0]) \
            | (image[:,:,1] < rgb_threshold[1]) \
            | (image[:,:,2] < rgb_threshold[2])
color_select[thresholds] = [0,0,0]

# Display the image                 
plt.imshow(color_select)
plt.show()