我是意大利博洛尼亚大学的一名学生，并且正在使用Google Coral USB加速器进行论文撰写。
我实现了一个keras神经网络，将我的数据分为四类，我得到的准确率大约为97％。
我执行了完整的整数训练后量化，因为keras网络不支持量化感知训练。我遵循TensorFlow网站上的指南，但是在边缘tpu上运行推理时遇到问题。
特别是当模型转换为tensorflowlite时，我的网络会遭受准确性损失（准确性下降到大约25％）。这是由于量化所致，因为在我的电脑上运行的tensorflowlite模型没有进行量化没有受到转换的影响。
我尝试使用MinMaxScaler在[0，255]范围内缩放输入数据，但是在这种情况下，即使tensorflowlite量化模型的精度与未转换的模型之一匹配，结果由于网络本身的准确性较低，因此不令人满意。
我想知道您是否可以帮助我解决这个问题。也许我的数据集上的值太低，量化无法将float32转换为uint8而没有信息丢失。
在下面，您将找到我的python代码。
from __future__ import absolute_import, division, print_function, unicode_literals
import tensorflow as tf
import numpy as np
import matplotlib.pyplot as plt
from numpy import loadtxt
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense
from sklearn.model_selection import train_test_split
from tensorflow.keras.utils import to_categorical
from tensorflow.keras.optimizers import RMSprop
from sklearn.preprocessing import StandardScaler,MinMaxScaler,Normalizer
from sklearn.metrics import confusion_matrix, accuracy_score
from tensorflow.keras.callbacks import EarlyStopping
import os
import time
import tflite_runtime.interpreter as tflite
import collections
import operator
"""Functions to work with classification models."""
Class = collections.namedtuple('Class', ['id', 'score'])
def input_tensor(interpreter):
"""Returns input tensor view as numpy array of shape (height, width, 3)."""
tensor_index = interpreter.get_input_details()[0]['index']
return interpreter.tensor(tensor_index)()[0]
def output_tensor(interpreter):
"""Returns dequantized output tensor."""
output_details = interpreter.get_output_details()[0]
output_data = np.squeeze(interpreter.tensor(output_details['index'])()) #Remove single-dimensional entries from the shape of an array.
scale, zero_point = output_details['quantization']
return scale * (output_data - zero_point)
def set_input(interpreter, data):
"""Copies data to input tensor."""
input_tensor(interpreter)[:] = data
return data
def get_output(interpreter, top_k=1, score_threshold=0.0):
"""Returns no more than top_k classes with score >= score_threshold."""
scores = output_tensor(interpreter)
classes = [
Class(i, scores[i])
for i in np.argpartition(scores, -top_k)[-top_k:]
if scores[i] >= score_threshold
]
return sorted(classes, key=operator.itemgetter(1), reverse=True)
#load the dataset
Modelli_Prova01_Nom01_Acc1L = loadtxt(r'/home/utente/Scrivania/csvtesi/Modelli_Prova01_Nom01_Acc1L.csv',delimiter=',')
Modelli_Prova02_Nom01_Acc1L = loadtxt(r'/home/utente/Scrivania/csvtesi/Modelli_Prova02_Nom01_Acc1L.csv',delimiter=',')
Modelli_Prova03_Nom01_Acc1L = loadtxt(r'/home/utente/Scrivania/csvtesi/Modelli_Prova03_Nom01_Acc1L.csv',delimiter=',')
Modelli_Prova04_Nom01_Acc1L = loadtxt(r'/home/utente/Scrivania/csvtesi/Modelli_Prova04_Nom01_Acc1L.csv',delimiter=',')
Modelli_Prova05_Nom01_Acc1L = loadtxt(r'/home/utente/Scrivania/csvtesi/Modelli_Prova05_Nom01_Acc1L.csv',delimiter=',')
time_start = time.perf_counter()
#split x and y data (train and test)
Acc1L01_train,Acc1L01_test = train_test_split(Modelli_Prova01_Nom01_Acc1L ,test_size=0.015,random_state=42)
Acc1L02_train,Acc1L02_test = train_test_split(Modelli_Prova02_Nom01_Acc1L,test_size=0.3,random_state=42)
Acc1L03_train,Acc1L03_test = train_test_split(Modelli_Prova03_Nom01_Acc1L,test_size=0.3,random_state=42)
Acc1L04_train,Acc1L04_test = train_test_split(Modelli_Prova04_Nom01_Acc1L,test_size=0.3,random_state=42)
Acc1L05_train,Acc1L05_test = train_test_split(Modelli_Prova05_Nom01_Acc1L,test_size=0.15,random_state=42)
Y1_train= np.zeros([len(Acc1L01_train)+len(Acc1L05_train),1])
Y2_train= np.ones([len(Acc1L02_train),1])
Y3_train= np.ones([len(Acc1L03_train),1]) +1
Y4_train= np.ones([len(Acc1L04_train),1]) +2
Y1_test= np.zeros([len(Acc1L01_test)+len(Acc1L05_test),1])
Y2_test= np.ones([len(Acc1L02_test),1])
Y3_test= np.ones([len(Acc1L03_test),1]) +1
Y4_test= np.ones([len(Acc1L04_test),1]) +2
xAcc1L_train = np.concatenate((Acc1L01_train,Acc1L05_train,Acc1L02_train,Acc1L03_train,Acc1L04_train),axis=0)
xAcc1L_train=MinMaxScaler([0,255]).fit_transform(xAcc1L_train)
#xAcc1L_train=StandardScaler().fit_transform(xAcc1L_train)
#xAcc1L_train=Normalizer().fit_transform(xAcc1L_train)
#xAcc1L_train=np.transpose(xAcc1L_train)
yAcc1L_train = np.concatenate((Y1_train,Y2_train,Y3_train,Y4_train),axis=0)
xAcc1L_test = np.concatenate((Acc1L01_test,Acc1L05_test,Acc1L02_test,Acc1L03_test,Acc1L04_test),axis=0)
xAcc1L_test=Normalizer().fit_transform(xAcc1L_test)
#xAcc1L_test=MinMaxScaler([0,255]).fit_transform(xAcc1L_test)
#xAcc1L_test=StandardScaler().fit_transform(xAcc1L_test)
#xAcc1L_test=np.transpose(xAcc1L_test)
yAcc1L_test = np.concatenate((Y1_test,Y2_test,Y3_test,Y4_test),axis=0)
#1 hot encode y
one_hot_labelsAcc1L =to_categorical(yAcc1L_train, num_classes=4)
one_hot_labelsAcc1L_test = to_categorical(yAcc1L_test, num_classes=4)
#fit the model
model = Sequential()
model.add(Dense(300, activation='relu', input_dim=30))
model.add(Dense(4, activation='softmax'))
model.compile(optimizer='rmsprop',
loss='categorical_crossentropy',
metrics=['accuracy'])
model.summary()
es1 = EarlyStopping(monitor='val_loss', mode='min', verbose=1, patience=100)
es2 = EarlyStopping(monitor='val_accuracy', mode='max', verbose=1, patience=100)
history=model.fit(xAcc1L_train, one_hot_labelsAcc1L,validation_data=(xAcc1L_test,one_hot_labelsAcc1L_test),epochs=500, batch_size=30, verbose=1, callbacks=[es1,es2])
#history=model.fit(tf.cast(xAcc1L_train, tf.float32), one_hot_labelsAcc1L,validation_data=(tf.cast(xAcc1L_test, tf.float32),one_hot_labelsAcc1L_test),epochs=500, batch_size=30, verbose=1, callbacks=[es1,es2])
time_elapsed = (time.perf_counter() - time_start)
print ("%5.1f secs " % (time_elapsed))
start=time.monotonic()
_, accuracy = model.evaluate(xAcc1L_test, one_hot_labelsAcc1L_test, batch_size=30, verbose=1)
#_, accuracy = model.evaluate(tf.cast(xAcc1L_test, tf.float32), one_hot_labelsAcc1L_test, batch_size=30, verbose=1)
print(accuracy)
inference_time = time.monotonic() - start
print('%.1fms ' % (inference_time * 1000))
# summarize history for accuracy
plt.plot(history.history['accuracy'])
plt.plot(history.history['val_accuracy'])
plt.title('model accuracy')
plt.ylabel('accuracy')
plt.xlabel('epoch')
plt.legend(['train', 'test'], loc='upper left')
plt.show()
# summarize history for loss
plt.plot(history.history['loss'])
plt.plot(history.history['val_loss'])
plt.title('model loss')
plt.ylabel('loss')
plt.xlabel('epoch')
plt.legend(['train', 'test'], loc='upper right')
plt.show()
#predicted labels
predictions = model.predict(xAcc1L_test)
y_pred = (predictions > 0.5)
matrix = confusion_matrix(one_hot_labelsAcc1L_test.argmax(axis=1), y_pred.argmax(axis=1))
print('confusion matrix = \n',matrix)
print("Accuracy:",accuracy_score(one_hot_labelsAcc1L_test.argmax(axis=1), y_pred.argmax(axis=1)))
mod01=model.save('/home/utente/Scrivania/csvtesi/rete_Nom01.h5')
#convert the model
#representative dataset
train_ds = tf.data.Dataset.from_tensor_slices(
(tf.cast(xAcc1L_train, tf.float32))).batch(1)
print(train_ds)
def representative_dataset_gen():
for input_value in train_ds:
yield [input_value]
print(model.layers[0].input_shape)
#integer post-training quantization
converter = tf.compat.v1.lite.TFLiteConverter.from_keras_model_file('/home/utente/Scrivania/csvtesi/rete_Nom01.h5') #all operations mapped on edge tpu
#converter = tf.lite.TFLiteConverter.from_keras_model(model)
converter.optimizations = [tf.lite.Optimize.DEFAULT]
converter.representative_dataset = representative_dataset_gen
print(converter.representative_dataset)
converter.target_spec.supported_ops = [tf.lite.OpsSet.TFLITE_BUILTINS_INT8]
converter.inference_input_type = tf.uint8
converter.inference_output_type = tf.uint8
tflite_quant_model = converter.convert()
open('/home/utente/Scrivania/csvtesi/rete_Nom01_quant.tflite', "wb").write(tflite_quant_model)
#compiler compila il modello quantizzato tflite per edge tpu
os.system("edgetpu_compiler \'/home/utente/Scrivania/csvtesi/rete_Nom01_quant.tflite'")
#interpret the model
interpreter = tf.lite.Interpreter('/home/utente/Scrivania/csvtesi/rete_Nom01_quant_edgetpu.tflite',experimental_delegates=[tflite.load_delegate('libedgetpu.so.1')])
interpreter.allocate_tensors()
idt=print(interpreter.get_input_details())
odt=print(interpreter.get_output_details())
for j in range(5):
start = time.monotonic()
o_test=np.arange(len(xAcc1L_test[:,0]))
o_test=o_test[:,np.newaxis]
for i in range (len(xAcc1L_test[:,0])):
input=set_input(interpreter, xAcc1L_test[i,:])
#print("inference input %s" % input)
interpreter.invoke()
classes = get_output(interpreter,4)
output = interpreter.get_tensor(interpreter.get_output_details()[0]['index'])#/255 con edgetpu
#print("inference output %s" % output)
#print("inference classes %s" % classes)
a=np.array([one_hot_labelsAcc1L_test[i,:].argmax(axis=0)])
b=np.array(output.argmax(axis=1))
o_test[i]=b
#if a==b:
#print('good classification')
#else:
#print('bad classification')
inference_time = time.monotonic() - start
print('%.1fms ' % (inference_time * 1000))
#print(o_test)
print("Accuracy:",accuracy_score(yAcc1L_test,o_test))
我的输入火车数据集是csv文件的一部分，它是维度=（1756,30）的矩阵，而我的输入测试之一是（183,30）的矩阵。 数据是这样的（前两行）：
[[-0.283589 -0.0831421 -0.199936 -0.144523 -0.215593 -0.199029 0.0300179 -0.0299262 -0.0759612 -0.0349733 0.102882 -0.00470235 -0.14267 -0.116636 -0.0842867 -0.124638 -0.107917 -0.0995006 -0.222817 -0.256093 -0.121859 -0.130829 -0.186091 -0.174511 -0.0715493 -0.0595195 -0.054914 -0.0362971 -0.0286576 -0.0409128],
[-0.226151 -0.0386177 -0.16834 -0.0768908 -0.166611 -0.161028 0.0493133 -0.00515959 -0.0362308 -0.00723895 0.105943 -0.010825 -0.142335 -0.10863 -0.0634201 -0.112928 -0.0927994 -0.0556194 -0.180721 -0.218341 -0.0934449 -0.100047 -0.134569 -0.119806 -0.0265749 -0.044841 -0.0538225 -0.017408 -0.00528171 -0.0248457]]