我在混淆矩阵上得到了非常糟糕的结果，但在最后一个epoch的val_set上训练了99.44%的准确率

Question

我的数据集有2个文件夹Test和Train, Test包含2个文件夹，里面有Covid X射线和Normal X射线，Train文件夹也是如此。在训练的最后一个epoch，我在val_set上得到99.4%的准确率，但是在绘制混淆矩阵时，我甚至没有得到60%的准确率。卡住了，请帮忙!而且我的Y_pred看起来很奇怪，而不是介于0-1之间的确定性，我需要帮助才能在我的混淆矩阵和分类报告上获得相同的99.4%的结果。

import os
import numpy as np
import matplotlib.pyplot as plt
import keras
from keras.applications import xception
from keras.layers import *
from keras.models import *
from keras.preprocessing import image
model = xception.Xception(weights='imagenet', include_top=False, input_shape=(224, 224, 3))
for layers in model.layers:
layers.trainable=False

flat1 = Flatten()(model.layers[-1].output)
class1 = Dense(256, activation='relu')(flat1)
output = Dense(1, activation='sigmoid')(class1)
model = Model(inputs = model.inputs, outputs = output)

model.compile(loss = 'binary_crossentropy', optimizer='adam', metrics=['accuracy'])

train_datagen = image.ImageDataGenerator(
rescale = 1./255,
shear_range = 0.2,
zoom_range = 0.2,
horizontal_flip = True,
)
test_datagen = image.ImageDataGenerator(rescale = 1./255)
train_generator = train_datagen.flow_from_directory(
'/Users/xd_anshul/Desktop/Research/Major/CovidDataset/Train',
target_size = (224,224),
batch_size = 10,
class_mode='binary')
validation_generator = test_datagen.flow_from_directory(
'/Users/xd_anshul/Desktop/Research/Major/CovidDataset/Test',
target_size = (224,224),
batch_size = 10,
class_mode='binary')
#model Fitting
hist = model.fit(
train_generator,
epochs=2,
validation_data=validation_generator)

from sklearn.metrics import classification_report, confusion_matrix
Y_pred = model.predict_generator(validation_generator, steps = np.ceil(validation_generator.samples / validation_generator.batch_size), verbose=1, workers=0)
y_pred = [np.where(predictions>0.5, 1, 0) for predictions in Y_pred]
print('Confusion Matrix')
print(confusion_matrix(validation_generator.classes, y_pred))
print('Classification Report')
target_names = ['Covid', 'Normal']
print(classification_report(validation_generator.classes, y_pred, target_names=target_names))
OUTPUT::
Epoch 1/2
255/255 [==============================] - 464s 2s/step - loss: 1.4076 - accuracy: 0.9342 - val_loss: 0.3753 - val_accuracy: 0.9718
Epoch 2/2
255/255 [==============================] - 558s 2s/step - loss: 0.1218 - accuracy: 0.9885 - val_loss: 0.0181 - val_accuracy: 0.9944
Confusion Matrix
[[310 100]
[ 97  25]]
Classification Report
precision    recall  f1-score   support
Covid       0.76      0.76      0.76       410
Normal       0.20      0.20      0.20       122
accuracy                           0.63       532
macro avg       0.48      0.48      0.48       532
weighted avg       0.63      0.63      0.63       532
Y_pred looks like:
1.05698e-14
2.25061e-13
3.96925e-19
5.53114e-17
3.4461e-32
1.2413e-32
2.29092e-28
4.01138e-17
3.81177e-23
1.88817e-07
1.164e-07
.
.
.
(532 Values)

Answer 1

你的问题是

y_pred = [np.where(predictions>0.5, 1, 0) for predictions in Y_pred]

打印出来，你会看到它是一个数组列表因为Y_pred是一个数组试试

y_pred=[ np.argmax(Y_pred[i]) for i in range(val_generator.samples)]