OpenCV Python Tutorial For Beginners - Road Lane Line Detection with OpenCV (Part 3)

detector.py

import matplotlib.pylab as plt
import cv2
import numpy as np

def region_of_interest(img, vertices):
    mask = np.zeros_like(img)
    #channel_count = img.shape[2]
    match_mask_color = 255
    cv2.fillPoly(mask, vertices, match_mask_color)
    masked_image = cv2.bitwise_and(img, mask)
    return masked_image

def drow_the_lines(img, lines):
    img = np.copy(img)
    blank_image = np.zeros((img.shape[0], img.shape[1], 3), dtype=np.uint8)

    for line in lines:
        for x1, y1, x2, y2 in line:
            cv2.line(blank_image, (x1,y1), (x2,y2), (0, 255, 0), thickness=10)

    img = cv2.addWeighted(img, 0.8, blank_image, 1, 0.0)
    return img

# = cv2.imread('road.jpg')
#image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
def process(image):
    print(image.shape)
    height = image.shape[0]
    width = image.shape[1]
    region_of_interest_vertices = [
        (0, height),
        (width/2, height/2),
        (width, height)
    ]
    gray_image = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)
    canny_image = cv2.Canny(gray_image, 100, 120)
    cropped_image = region_of_interest(canny_image,
                    np.array([region_of_interest_vertices], np.int32),)
    lines = cv2.HoughLinesP(cropped_image,
                            rho=2,
                            theta=np.pi/180,
                            threshold=50,
                            lines=np.array([]),
                            minLineLength=40,
                            maxLineGap=100)
    image_with_lines = drow_the_lines(image, lines)
    return image_with_lines

cap = cv2.VideoCapture('test.mp4')

while cap.isOpened():
    ret, frame = cap.read()
    frame = process(frame)
    cv2.imshow('frame', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

In line 17 for line in line: TypeError: 'NoneType' object is not iterable

In line 17 for line in line: TypeError: 'NoneType' object is not iterable

it means the second line variable is none.
i think u have to fix it into: "for line in lines"

how can I download the test.mp4 ?

@priyanshumittal8 It doesn't have to be a specific clip, you can download any clip which contains the lane, and then name it test.mp4, and give the location of the clip or paste it in the folder which contains the detector.py

In line 17 for line in line: TypeError: 'NoneType' object is not iterable

@akbloodadarsh It means value of "lines" is None. Try exception handling.
if lines is None:
image_with _lines = image
else:
image_with_lines = draw_the _lines(image, lines)
Hope this could work for you.

how can I download the test.mp4 ?

@priyanshumittal8 You can use any clip which contains the lane. Try this https://www.youtube.com/watch?v=6q5_A5wOwDM

@akbloodadarsh , @yashanmick Thank you

though it was supposed to get an image, it's getting none
[

](url)

AttributeError Traceback (most recent call last)
in
46 while cap.isOpened():
47 ret, frame = cap.read()
---> 48 frame = process(frame)
49 cv2.imshow('frame', frame)
50 if cv2.waitKey(1) & 0xFF == ord('q'):

in process(image)
20
21 def process(image):
---> 22 print(image.shape)
23 height = image.shape[0]
24 width = image.shape[1]

AttributeError: 'NoneType' object has no attribute 'shape'
how to fix this

AttributeError Traceback (most recent call last)
in
46 while cap.isOpened():
47 ret, frame = cap.read()
---> 48 frame = process(frame)
49 cv2.imshow('frame', frame)
50 if cv2.waitKey(1) & 0xFF == ord('q'):

in process(image)
20
21 def process(image):
---> 22 print(image.shape)
23 height = image.shape[0]
24 width = image.shape[1]

AttributeError: 'NoneType' object has no attribute 'shape'
how to fix this

region_of_interest_vertices = [
(0, height), (width / 2, height / 2), (width, height)
]
This code is used for the setting area of interest. If you pass any appropriate values in it then it shows NoneTye object has no attribute shape. So check your dimensions of the area of interest.

AttributeError Traceback (most recent call last)
in
46 while cap.isOpened():
47 ret, frame = cap.read()
---> 48 frame = process(frame)
49 cv2.imshow('frame', frame)
50 if cv2.waitKey(1) & 0xFF == ord('q'):

in process(image)
20
21 def process(image):
---> 22 print(image.shape)
23 height = image.shape[0]
24 width = image.shape[1]

AttributeError: 'NoneType' object has no attribute 'shape'
how to fix this

Check video path

Sir, I am facing some issues regarding different video qualities. The code is running well and detecting the lanes for 1280X720 resolution videos. But for some videos with other than the resolution, the output tab is not showing. The code even is not showing any error. How can I resolve this problem?

how can I download the test.mp4 ?

you can download it from here https://www.kaggle.com/datasets/dpamgautam/video-file-for-lane-detection-project?resource=download

Hello! thanks very much for this Tutorial ,I want instead of using the video to work with raspberry camera what should I do?