Train Validation data split - labels available but

my studies project is to develop a neural network to recognize text on license plates. Therefore, I found the ReId-dataset at https://medusa.fit.vutbr.cz/traffic/research-topics/general-traffic-analysis/holistic-recognition-of-low-quality-license-plates-by-cnn-using-track-annotated-data-iwt4s-avss-2017/. This dataset contains a bunch of images of number plates as well as the text of the license plates and was used by Spanhel et al. for a similar approach as the one I have in mind.

Example of a license plate there:

In the project I want to recognize only the license plate text, i.e. only "9B5 2145" and not the country acronym "CZ" and no advertisement text.

I downloaded the dataset and the labels csv-file to my local memory. So, I have the following folder structure: One mother directory for my whole project. This mother directory includes my data directory, where I stored the ReId dataset. This dataset includes several subdirectories, 4 directories with training data and 4 with test data, all of this subdirectories contain a number of images of license plates. The ReId dataset also contains the trainVal csv-file which is structured as follows (snippet of the actual sheet):

track_id is equal to the subdirectory of the ReID dataset. image_path is equal to the path to the image, in this case the image's name is 1_1. lp is the label of the license plate, so the actual license plate. train is a dummy variable, equal to one, if the image is used for training purposes and 0 for validation purposes.

Regarding this dataset, I got three main questions:

How do I read in this images properly? I tried to use something like this

from keras.preprocessing.image import ImageDataGenerator

# create generator
datagen = ImageDataGenerator()

# prepare an iterators for each dataset
train_it = datagen.flow_from_directory('data/train/', class_mode='binary')
val_it = datagen.flow_from_directory('data/validation/', class_mode='binary')
test_it = datagen.flow_from_directory('data/test/', class_mode='binary')

# confirm the iterator works
batchX, batchy = train_it.next()
print('Batch shape=%s, min=%.3f, max=%.3f' % (batchX.shape, batchX.min(), batchX.max()))

But obviously Python did not find images belonging to any classes (side note: I used the correct paths). That is clear to me, because I did not assign any class to my data yet. So, my first question is: Do I have to do that? I don't think so.

How do I then read this images properly? I think, I have to get numpy arrays to work properly with this data.
How do I bring my images and the labels together? In my opinion, I think I have to merge the two datasets, don't I?

Thank you very much!

Question 1 and 2:

For reading the images, imread from matplotlib.pyplot can be used as shown in the example, this does not require any classes to be set.

Question 3:

The labels and images can be brought together by storing the corresponding license plate number in an output array (y in the example) for each image (stored in the xs array in the example) in the data array. You don't necessarily need to merge them.

Hope I helped!

import os
import matplotlib.pyplot as plt
import numpy as np 
import pandas as pd

xs, y = [], []
main_dir = './sample/dataset' # the main directory 
label_data = pd.read_csv('labels.csv')

for folder in os.listdir(main_dir):
    for img in os.listdir(os.path.join(main, folder)):
        arr = plt.imread(os.path.join(main, folder) + img)
        xs.append(arr)
        y.append(label_data[label_data['image_path'] == os.path.join(folder, img)]['lp'])
                #^ this part can be changed depending on the exact format of your label data file.

# then you can convert them into numpy arrays and reshape them as you need.
xs = np.array(xs)
y = np.array(y)