

In [33]:

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


image = mpimg.imread('testimg.jpg')

ysize = image.shape[0]
xsize = image.shape[1]
color_select = np.copy(image)
line_image = np.copy(image)

red_threshold = 200
green_threshold = 200
blue_threshold = 200

rgb_threshold = [red_threshold, green_threshold, blue_threshold]

left_bottom = [-10, 750]
right_bottom = [1250, 750]
apex = [650, 400]

fit_left = np.polyfit((left_bottom[0], apex[0]), (left_bottom[1], apex[1]), 1)
fit_right = np.polyfit((right_bottom[0], apex[0]), (right_bottom[1], apex[1]), 1)
fit_bottom = np.polyfit((left_bottom[0], right_bottom[0]), (left_bottom[1], right_bottom[1]), 1)

color_thresholds = (image[:,:,0] < rgb_threshold[0]) | \
                    (image[:,:,1] < rgb_threshold[1]) | \
                    (image[:,:,2] < rgb_threshold[2])

XX, YY = np.meshgrid(np.arange(0, xsize), np.arange(0, ysize))
region_thresholds = (YY > (XX*fit_left[0] + fit_left[1])) & \
                    (YY > (XX*fit_right[0] + fit_right[1])) & \
                    (YY < (XX*fit_bottom[0] + fit_bottom[1]))
                    
color_select[color_thresholds | ~region_thresholds] = [0, 0, 0]

# Color pixels red where both color and region selections met
line_image[~color_thresholds & region_thresholds] = [255, 0, 0]

# Display the image and show region and color selections
plt.imshow(image)
x = [left_bottom[0], right_bottom[0], apex[0], left_bottom[0]]
y = [left_bottom[1], right_bottom[1], apex[1], left_bottom[1]]
plt.plot(x, y, 'g--', lw=2)
plt.imshow(color_select)
plt.imshow(line_image)
plt.show()