Can somebody explain me this method? CNN Keras - starter

Question

def ReadImages(Path):
    LabelList = list()
    ImageCV = list()
    classes = ["nonPdr", "pdr"]

    FolderList = [f for f in os.listdir(Path) if not f.startswith('.')]

    for File in FolderList:
        for index, Image in enumerate(os.listdir(os.path.join(Path, File))):
            ImageCV.append(cv2.resize(cv2.imread(os.path.join(Path, File) + os.path.sep + Image), (224,224)))
            LabelList.append(classes.index(os.path.splitext(File)[0])) 
            print(FolderList)
    return ImageCV, LabelList

I got this method, and I'm not understanding properly what it do line by line, can someone help me?

Answer 1

def ReadImages(Path):  #path to dir with all images
    LabelList = list() #Initialized empty labels list
    ImageCV = list()   #Initialized empty ImageCV list initialized
    classes = ["nonPdr", "pdr"]  #classes labels all image files startwith
    #return list of image folders in main dir path/
    FolderList = [f for f in os.listdir(Path) if not f.startswith('.')]

    #loop over dir of image folders
    for File in FolderList:
        #for loop returns index of each image in a image folder 
        #and the image name
        for index, Image in enumerate(os.listdir(os.path.join(Path, File))):
            #Read image file resize it and append it to ImageCv list
            ImageCV.append(cv2.resize(cv2.imread(os.path.join(Path, File) + os.path.sep + Image), (224,224)))
            #return string of characters before dot 1 in file name 
            #return index from classes !!!dangerous line assumes all files 
            #of form nonPdr.* or pdr.*
            #append that index value either 1 or 0 to libelist
            LabelList.append(classes.index(os.path.splitext(File)[0]))  
            print(FolderList) # print the folder just parsed
    return ImageCV, LabelList # return the two list created at the start
    #now containing images and labels based on names of image files

Answer 2

Answers will be put together as comments on your code

def ReadImages(Path):
    LabelList = list() ## Get empty list for labels
    ImageCV = list() #Empty list for images
    classes = ["nonPdr", "pdr"]

    FolderList = [f for f in os.listdir(Path) if not f.startswith('.')] 
    #Collect names of all folders within path, ignore those files that starts with dot

    for File in FolderList:
        # The structure of the directory is assumed to be : Path contains folders and images are contained within these folders.
        # We iterate for each image within the each folder
        for index, Image in enumerate(os.listdir(os.path.join(Path, File))):

            # We read and resized to (224,224) and store it in our list 
            # The file will be read from "Path/File/(image file name).(image extensions)"
            ImageCV.append(cv2.resize(cv2.imread(os.path.join(Path, File) + os.path.sep + Image), (224,224)))

            # After that labels for each image is determined by its filename (if nonPdr label is 0, if filename is Pdr label is 1)
            LabelList.append(classes.index(os.path.splitext(File)[0])) 
            print(FolderList)

    #Return Result
    return ImageCV, LabelList