почему извлеченные функции имеют много нуля я keras vgg16?

Question

это мой код, я избавляюсь от последних плотных слоев и предсказываю особенности.

import pandas as pd
import numpy as np
import tensorflow as tf
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Convolution2D, MaxPooling2D, Flatten, Dense, Dropout, GlobalAveragePooling2D
from tensorflow.keras.applications import VGG16
from tensorflow.keras.models import Sequential 
from tensorflow.keras.layers import Conv2D, MaxPooling2D 
from tensorflow.keras.layers import Dense, Dropout 
from tensorflow.keras.layers import Flatten, BatchNormalization
import os, shutil
from keras.preprocessing.image import ImageDataGenerator
import keras 

conv_base = VGG16(weights='imagenet', 
                  include_top=False,
                  input_shape=(img_width, img_height, 3))

train_dir = "/content/drive/My Drive/small_data/data/train"
valid_dir = "/content/drive/My Drive/small_data/data/validation"

datagen = ImageDataGenerator(rescale=1./155)
batch_size = 1

img_width, img_height = 224, 224 

def extract_features(directory, sample_count):
    features = np.zeros(shape=(sample_count, 7, 7, 512))  # Must be equal to the output of the convolutional base
    labels = np.zeros(shape=(sample_count,6))
    # Preprocess data
    generator = datagen.flow_from_directory(directory,
                                            target_size=(img_width,img_height),
                                            batch_size = batch_size,
                                            class_mode='binary')
    # Pass data through convolutional base
    i = 0
    for inputs_batch, labels_batch in generator:
        features_batch = conv_base.predict(inputs_batch)
        features[i * batch_size: (i + 1) * batch_size] = features_batch
        labels[i * batch_size: (i + 1) * batch_size] = labels_batch
        i += 1
        if i * batch_size >= sample_count:
            break
    return features, labels


train_features, train_labels = extract_features(train_dir, 43)
validation_features, validation_labels = extract_features(valid_dir, 28)

значение, которое я получаю, когда печатаю жесты поезда, - это просто большой список с такими числами (0 ., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.08844849, 0.40013123, 0., 0., 0., 0., 0., 0. , 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.59819716, 0., 0., 0., 0.03238258, 0., 0., 0., 0.32838312, 0.42723358, 0.10626598, 0., 0.1936072, 0.71200961, 0.38265556, 0.06889667, 0.3056691, 0.35969719, 0., 0., 0., 0., 0., 0., 0., 0., 0., 0. , 0., 0., 0.9093371, 0.17480908, 0., 0., 0.07098073, 0.41668156, 0., 0., 0., 0., 0.93668669, 0., 0., 0., 1.08008015, 0., 0.24190509 , 1.52572215), как вы можете видеть, в функциях много нуля, поэтому я хочу знать, почему?