Validation Loss Increases every iteration - tensorflow

Question

Recently I have been trying to do multi-class classification. My datasets consist of 17 image categories. Previously I was using 3 conv layers and 2 hidden layers. It resulted my model overfitting with huge validation loss around 11.0++ and my validation accuracy was very low. So I decided to decrease the conv layers by 1 and hidden layer by 1. I also have removed dropout and it still have the same problem with the validation which still overfitting, even though my training accuracy and loss are getting better.
Here is my code for prepared datasets:
import cv2
import numpy as np
import os
import pickle
import random
CATEGORIES = ["apple_pie", "baklava", "caesar_salad","donuts",
"fried_calamari", "grilled_salmon", "hamburger",
"ice_cream", "lasagna", "macaroni_and_cheese", "nachos", "omelette","pizza",
"risotto", "steak", "tiramisu", "waffles"]
DATALOC = "D:/Foods/Datasets"
IMAGE_SIZE = 50
data_training = []
def create_data_training():
for category in CATEGORIES:
path = os.path.join(DATALOC, category)
class_num = CATEGORIES.index(category)
for image in os.listdir(path):
try:
image_array = cv2.imread(os.path.join(path,image), cv2.IMREAD_GRAYSCALE)
new_image_array = cv2.resize(image_array, (IMAGE_SIZE,IMAGE_SIZE))
data_training.append([new_image_array,class_num])
except Exception as exc:
pass
create_data_training()
random.shuffle(data_training)
X = []
y = []
for features, label in data_training:
X.append(features)
y.append(label)
X = np.array(X).reshape(-1, IMAGE_SIZE, IMAGE_SIZE, 1)
y = np.array(y)
pickle_out = open("X.pickle", "wb")
pickle.dump(X, pickle_out)
pickle_out.close()
pickle_out = open("y.pickle", "wb")
pickle.dump(y, pickle_out)
pickle_out.close()
pickle_in = open("X.pickle","rb")
X = pickle.load(pickle_in)
Here is the code of my model:
import pickle
import tensorflow as tf
import time
from tensorflow.keras.models import Sequential
from tensorflow.keras.callbacks import TensorBoard
from tensorflow.keras.layers import Activation, Conv2D, Dense, Dropout, Flatten, MaxPooling2D
NAME = "Foods-Model-{}".format(int(time.time()))
tensorboard = TensorBoard(log_dir='logs\{}'.format(NAME))
X = pickle.load(open("X.pickle","rb"))
y = pickle.load(open("y.pickle","rb"))
X = X/255.0
model = Sequential()
model.add(Conv2D(32,(3,3), input_shape = X.shape[1:]))
model.add(Activation("relu"))
model.add(MaxPooling2D(pool_size =(2,2)))
model.add(Conv2D(64,(3,3)))
model.add(Activation("relu"))
model.add(MaxPooling2D(pool_size =(2,2)))
model.add(Flatten())
model.add(Dense(128))
model.add(Activation("relu"))
model.add(Dense(17))
model.add(Activation('softmax'))
model.compile(loss = "sparse_categorical_crossentropy", optimizer = "adam", metrics = ['accuracy'])
model.fit(X, y, batch_size = 16, epochs = 20 , validation_split = 0.1, callbacks = [tensorboard])
The result of the trained model:
Train on 7650 samples, validate on 850 samples
Epoch 1/20
7650/7650 [==============================] - 242s 32ms/sample - loss: 2.7826 - accuracy: 0.1024 - val_loss: 2.7018 - val_accuracy: 0.1329
Epoch 2/20
7650/7650 [==============================] - 241s 31ms/sample - loss: 2.5673 - accuracy: 0.1876 - val_loss: 2.5597 - val_accuracy: 0.2059
Epoch 3/20
7650/7650 [==============================] - 234s 31ms/sample - loss: 2.3529 - accuracy: 0.2617 - val_loss: 2.5329 - val_accuracy: 0.2153
Epoch 4/20
7650/7650 [==============================] - 233s 30ms/sample - loss: 2.0707 - accuracy: 0.3510 - val_loss: 2.6628 - val_accuracy: 0.2059
Epoch 5/20
7650/7650 [==============================] - 231s 30ms/sample - loss: 1.6960 - accuracy: 0.4753 - val_loss: 2.8143 - val_accuracy: 0.2047
Epoch 6/20
7650/7650 [==============================] - 230s 30ms/sample - loss: 1.2336 - accuracy: 0.6247 - val_loss: 3.3130 - val_accuracy: 0.1929
Epoch 7/20
7650/7650 [==============================] - 233s 30ms/sample - loss: 0.7738 - accuracy: 0.7715 - val_loss: 3.9758 - val_accuracy: 0.1776
Epoch 8/20
7650/7650 [==============================] - 231s 30ms/sample - loss: 0.4271 - accuracy: 0.8827 - val_loss: 4.7325 - val_accuracy: 0.1882
Epoch 9/20
7650/7650 [==============================] - 233s 30ms/sample - loss: 0.2080 - accuracy: 0.9519 - val_loss: 5.7198 - val_accuracy: 0.1918
Epoch 10/20
7650/7650 [==============================] - 233s 30ms/sample - loss: 0.1402 - accuracy: 0.9668 - val_loss: 6.0608 - val_accuracy: 0.1835
Epoch 11/20
7650/7650 [==============================] - 236s 31ms/sample - loss: 0.0724 - accuracy: 0.9872 - val_loss: 6.7468 - val_accuracy: 0.1753
Epoch 12/20
7650/7650 [==============================] - 232s 30ms/sample - loss: 0.0549 - accuracy: 0.9895 - val_loss: 7.4844 - val_accuracy: 0.1718
Epoch 13/20
7650/7650 [==============================] - 229s 30ms/sample - loss: 0.1541 - accuracy: 0.9591 - val_loss: 7.3335 - val_accuracy: 0.1553
Epoch 14/20
7650/7650 [==============================] - 231s 30ms/sample - loss: 0.0477 - accuracy: 0.9905 - val_loss: 7.8453 - val_accuracy: 0.1729
Epoch 15/20
7650/7650 [==============================] - 233s 30ms/sample - loss: 0.0346 - accuracy: 0.9908 - val_loss: 8.1847 - val_accuracy: 0.1753
Epoch 16/20
7650/7650 [==============================] - 231s 30ms/sample - loss: 0.0657 - accuracy: 0.9833 - val_loss: 7.8582 - val_accuracy: 0.1624
Epoch 17/20
7650/7650 [==============================] - 233s 30ms/sample - loss: 0.0555 - accuracy: 0.9830 - val_loss: 8.2578 - val_accuracy: 0.1553
Epoch 18/20
7650/7650 [==============================] - 230s 30ms/sample - loss: 0.0423 - accuracy: 0.9892 - val_loss: 8.6970 - val_accuracy: 0.1694
Epoch 19/20
7650/7650 [==============================] - 236s 31ms/sample - loss: 0.0291 - accuracy: 0.9927 - val_loss: 8.5275 - val_accuracy: 0.1882
Epoch 20/20
7650/7650 [==============================] - 234s 31ms/sample - loss: 0.0443 - accuracy: 0.9873 - val_loss: 9.2703 - val_accuracy: 0.1812
Thank You for your time. Any help and suggestion will be really appreciated.

Answer 1

Your model suggests early over-fitting.
Get rid of the dense layer completely and use global pooling.
model = Sequential()
model.add(Conv2D(32,(3,3), input_shape = X.shape[1:]))
model.add(Activation("relu"))
model.add(Conv2D(64,(3,3)))
model.add(Activation("relu"))
model.add(Conv2D(128,(3,3)))
model.add(Activation("relu"))
model.add(GlobalAveragePooling2D())
model.add(Dense(17))
model.add(Activation('softmax'))
model.summary()
Use SpatialDropout2D after conv layers.
ref: https://www.tensorflow.org/api_docs/python/tf/keras/layers/SpatialDropout2D
Use early stopping to get a balanced model.
Your output suggests categorical_crossentropy as a better-fit loss.