lanes.py

import cv2
import numpy as np

def make_coordinates(image, line_parameters):
  slope, intercept = line_parameters
  y1 = image.shape[0]
  y2 = int(y1*(3/5))
  x1 = int((y1 - intercept)/slope)
  x2 = int((y2 - intercept)/slope)
  return np.array([x1, y1, x2, y2])

def average_slope_intercept(image, lines):
  left_fit = []
  right_fit = []
  for line in lines:
    x1, y1, x2, y2 = line.reshape(4)
    parameters = np.polyfit((x1, x2), (y1, y2), 1)
    slope = parameters[0]
    intercept = parameters[1]
    if slope<0:
      left_fit.append((slope, intercept))
    else:
      right_fit.append((slope, intercept))
  left_fit_average = np.average(left_fit, axis = 0)
  right_fit_average = np.average(right_fit, axis = 0)
  left_line = make_coordinates(image, left_fit_average)
  right_line = make_coordinates(image, right_fit_average)
  return np.array([left_line, right_line])

def canny(image):
  gray = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)
  blur = cv2.GaussianBlur(gray, (5, 5), 0)
  canny = cv2.Canny(blur, 50, 50)
  return canny

def display_lines(image, lines):
  line_image = np.zeros_like(image)
  if lines is not None:
    for x1, y1, x2, y2 in lines:
      cv2.line(line_image, (x1, y1), (x2, y2), (255, 0, 0), 10)
  return line_image


def region_of_interest(image):
  height = image.shape[0]
  polygons = np.array([
  [(200, height), (1100, height), (550, 250)]
  ])
  mask = np.zeros_like(image)
  cv2.fillPoly(mask, polygons, 255)
  masked_image = cv2.bitwise_and(image, mask)
  return masked_image

# image = cv2.imread('test_image.jpg')
# lane_image = np.copy(image)
# canny_image = canny(lane_image)
# cropped_image = region_of_interest(canny_image)
# lines = cv2.HoughLinesP(cropped_image, 2, np.pi/180, 100, np.array([]), minLineLength=40, maxLineGap=5)
# averaged_lines = average_slope_intercept(lane_image, lines)
# line_image = display_lines(lane_image,averaged_lines)
# combo_image = cv2.addWeighted(lane_image, 0.75, line_image, 1, 1)
# cv2_imshow(combo_image)

cap = cv2.VideoCapture("test2.mp4")
while(cap.isOpened()):
  _, frame = cap.read()
  canny_image = canny(frame)
  cropped_image = region_of_interest(canny_image)
  lines = cv2.HoughLinesP(cropped_image, 2, np.pi/180, 100, np.array([]), minLineLength=40, maxLineGap=5)
  averaged_lines = average_slope_intercept(frame, lines)
  line_image = display_lines(frame,averaged_lines)
  combo_image = cv2.addWeighted(frame, 0.75, line_image, 1, 1)
  cv2_imshow(combo_image)
  if cv2.waitKey(1) & 0xFF == ord('q'):
    break
cap.release()
cv2.destroyAllWindows()