使用迁移学习和 TensorFlow 进行食品分类
介绍
执行
步骤 1:导入库
请注意,我命令使用的 TensorFlow 是 2.4.1 版本,因此请安装该版本。
下载 CUDA 软件 https://developer.nvidia.com/cuda-11.0-download-archive
# ! pip install pandas
# ! pip install numpy
import os
import numpy as np
import pandas as pd
import tensorflow as tf
步骤2:准备数据
https://www.kaggle.com/binhminhs10/food5k
X = []
y = []
path = 'Food-5K/' + dtype + '/'
for i in os.listdir(path):
# Image
X.append(i)
# Label
y.append(i.split('_')[0])
X = np.array(X)
y = np.array(y)
df = pd.DataFrame()
df['filename'] = X
df['label'] = y
return df
df_train = dframe('training')
df_val = dframe('validation')
df_test = dframe('evaluation')
train_datagen = ImageDataGenerator(
featurewise_center=True,
featurewise_std_normalization=True,
rotation_range=20,
width_shift_range=0.2,
height_shift_range=0.2,
horizontal_flip=True,
)
val_datagen = ImageDataGenerator(
featurewise_center=True,
featurewise_std_normalization=True,
rotation_range=20,
width_shift_range=0.2,
height_shift_range=0.2,
horizontal_flip=True,
)
# Generate batches and augment the images
train_generator = train_datagen.flow_from_dataframe(
df_train,
directory='Food-5K/training/',
x_col='filename',
y_col='label',
class_mode='binary',
target_size=(224, 224),
)
val_generator = train_datagen.flow_from_dataframe(
df_val,
directory='Food-5K/validation/',
x_col='filename',
y_col='label',
class_mode='binary',
target_size=(224, 224),
)
步骤3:训练模型
# Initialize the Pretrained Model
feature_extractor = ResNet50(weights='imagenet',
input_shape=(224, 224, 3),
include_top=False)
# Set this parameter to make sure it's not being trained
feature_extractor.trainable = False
# Set the input layer
input_ = tf.keras.Input(shape=(224, 224, 3))
# Set the feature extractor layer
x = feature_extractor(input_, training=False)
# Set the pooling layer
x = tf.keras.layers.GlobalAveragePooling2D()(x)
# Set the final layer with sigmoid activation function
output_ = tf.keras.layers.Dense(1, activation='sigmoid')(x)
# Create the new model object
model = tf.keras.Model(input_, output_)
# Compile it
model.compile(optimizer='adam',
loss='binary_crossentropy',
metrics=['accuracy'])
# Print The Summary of The Model
model.summary()
步骤4:测试模型
from sklearn.metrics import classification_report, confusion_matrix
y_true = []
y_pred = []
for i in os.listdir('Food-5K/evaluation'):
img = Image.open('Food-5K/evaluation/' + i)
img = img.resize((224, 224))
img = np.array(img)
img = np.expand_dims(img, 0)
y_true.append(int(i.split('_')[0]))
y_pred.append(1 if model.predict(img) > 0.5 else 0)
print(classification_report(y_true, y_pred))
print()
print(confusion_matrix(y_true, y_pred))
从前面的内容可以看出,该模型的性能已超过95%。因此,我们可以在建立图像分类器 API 的情况下接受此模型。