How to check if an image contains an element I am searchig for

[Arak Rachael]

On Thursday, 17 June 2021 at 08:52:55 UTC+2, Peter J. Holzer wrote:
> On 2021-06-16 15:51:49 -0700, Arak Rachael wrote: 
> > On Wednesday, 16 June 2021 at 23:44:02 UTC+2, Chris Angelico wrote: 
> > > On Thu, Jun 17, 2021 at 7:35 AM Dan Stromberg <drsa... at gmail.com> wrote: 
> > > > 
> > > > On Wed, Jun 16, 2021 at 2:04 PM Barry <ba... at barrys-emacs.org> wrote: 
> > > > 
> > > > > >>> On Thu, Jun 17, 2021 at 6:06 AM Arak Rachael <arakelt... at gmail.com> 
> > > > > wrote: 
> > > > > >>> I have an image from google maps to say and I need to check if it has 
> > > > > road markings, in order to do that, I believe I need to change the effects 
> > > > > on the image so the markings and road can be white or something and the 
> > > > > things I don't need like cars, trees and so on to be black.
> [...]
> > I understand your concerns. Actually I am doing image processing of 
> > satellite pictures for smart cars.
> Using satellite images probably makes that a lot easier (yes, you wrote 
> "Google maps", but for some reason I thought of Google Street View). At 
> least you have a consistent angle (almost from straight above) and know 
> the scale (given the zoom factor and the latitude). 
> 
> hp 
> 
> -- 
> _ | Peter J. Holzer | Story must make more sense than reality. 
> |_|_) | | 
> | | | h... at hjp.at | -- Charles Stross, "Creative writing 
> __/ | http://www.hjp.at/ | challenge!"
I made the crop code, before I posted the question, I just need the identification part:
[code]
                                                        # Library includes
import os
import cv2                                              # image and other special formats processing library
                                                        # for computer vision
import numpy as np
from numpy import asarray
import PIL
from PIL import Image

                                                        # Global variables
                                                        # Recommended: move to a separate file

                                                        # Recommended approach instead of using the "target"
                                                        # name directly
source_directory = "test"                               # Do not put a slash at the beginning
output_directory = "test2"                              # Do not put a slash at the beginning

                                                        # Function definitions
def image_contains_required_elements(image):            # Description:
                                                        # The function will check if the  cropped image contains the
                                                        # required elements of the road(markings, road and others)

                                                        # Local variables and initialization
    raise Exception("Not implemented yet")



def split_image(path, dstpath):                         # Description:
                                                        # Convert the generated frames(images) from
                                                        # extract_video(video_path, target_dir_path) to grayscale
                                                        # and reduce their size to half

                                                        # Local variables and initialization
                                                        # Requires the libraries:
                                                        # import cv2
                                                        # import os
                                                        # import pytest
                                                        # import numpy as np

                                                        # Processing
                                                        # Reading an image in default mode
    #path = r'/home/yordan/devel/python.assignments/topgis-viz.2/data'                  # Source Folder
    #dstpath = r'/home/yordan/devel/python.assignments/topgis-viz.2/output_directory'            # Destination Folder

    #path = source_directory  # source_directory containing the images before the processing
    #dstpath = output_directory  # output_directory containing the images after the processing
    """
                                                        # Test if target_directory exists
    try:                                                # Try
        makedirs(dstpath)  # to create target_directory
    except:                                             # if there is an error
        print("Directory already exist, images will be written in same folder")  # print the error message
    """
    files = os.listdir(path)                            # Read the files from source_directory and record them in a list

    for image in files:                                 # For index in list
        img = cv2.imread(os.path.join(path, image))     # Read the image from path + image name as an array into img

                                                        # Split image into b, g ,r function
        gray = img
        #b, g, r = cv2.split(gray)                      # Split the image into BGR channels
        #print(b, g, r)                                 # print the b, g, r channels(codes)
        crop_img = gray[100:100 + 100, 100:100 + 100]   # Crop the image with numpy, x and y are flipped,
                                                        # example crop_img = img[margin:-margin, margin:-margin]
        if image_contains_required_elements(crop_img) == True:
            cv2.imwrite(os.path.join(dstpath, image), crop_img) # Write the image crop_img to a file with name
                                                        # target_directory + image name

                                                        # Displaying the image
        #cv2.imshow("Test", crop_img)                   # Show the image


split_image(source_directory, output_directory)
[code]