ResNet基本介绍
ResNet（Residual Network）是一种深度神经网络架构，由微软研究院的Kaiming He等人在2015年提出，并且在ILSVRC 2015竞赛中取得了很好的成绩。ResNet主要解决了随着网络深度增加而出现的退化问题，即当网络变得非常深时，训练误差和验证误差可能会开始上升，这并不是因为过拟合，而是由于深层网络难以优化。
ResNet的核心思想是引入了残差学习框架来简化许多层网络的训练。通过构建“跳跃连接”或称“捷径连接”，允许一层直接与更深层相连接。这种设计让网络可以学习到一个残差函数，相对于传统的学习未参考输入x的目标映射H(x)，残差块学习的是F(x) = H(x) - x。这样的结构使得信息能够跨过多层流动，从而缓解了梯度消失/爆炸的问题，也使得训练更深的网络成为可能。
残差块
残差块（Residual Block）是构成ResNet（Residual Network）的核心组件，它通过引入所谓的“跳跃连接”或“捷径连接”来解决深层网络训练中的梯度消失/爆炸问题。这种设计允许信息在多层之间直接传递，从而帮助优化非常深的神经网络。
残差块的核心思想是让网络去学习输入和输出之间的差异，也就是所谓的“残差”，而不是直接学习原始的输入到输出的映射。用数学语言来说，就是：
- 传统方法：网络尝试学习H(x)，即从输入x直接得到输出H(x)。
- 残差方法：网络学习的是F(x) = H(x) - x，即输入x与期望输出H(x)之间的差值。然后，实际的输出是由原输入加上这个差值得到，即H(x) = F(x) + x。
为什么这样做有效？
-
简化学习任务：相比于学习复杂的非线性映射H(x)，学习残差F(x)可能要简单得多。特别是当H(x)接近于x时（例如，对于一些层来说不需要对输入进行太多改变），此时F(x)可以趋近于0，表示这些层只需学会恒等映射即可，这比学习复杂的变换要容易很多。
-
缓解梯度问题：由于信息可以通过跳跃连接直接传递给后面的层，因此即使在深层网络中，早期层的信息也不会因为经过多层而完全丢失，从而减轻了梯度消失/爆炸的影响。
-
提高模型性能：通过允许网络更深，同时保持良好的可训练性，ResNet能够实现更高的准确率，并且在多个视觉任务上取得了当时最佳的结果。
一个基本的残差块结构如图所示：
(图源:7.6. 残差网络（ResNet） — 动手学深度学习 2.0.0 documentation)
一个典型的残差块包含以下几个部分：
- 卷积层：通常是一个或多个3x3的卷积层。这些层执行常规的特征提取任务。
- 批量归一化层（Batch Normalization, BN）：每个卷积层后紧跟着一个批量归一化层，以加速收敛过程并提高模型的泛化能力。
- ReLU激活函数：除了最后一个卷积层之后，其余卷积层之后都会应用ReLU激活函数来引入非线性。
- 跳跃连接：这是残差块最独特的部分。它将输入直接加到经过上述处理后的输出上。如果输入和输出具有相同的尺寸（即相同数量的通道数和空间维度），则可以直接相加；如果它们不同，则需要使用额外的1x1卷积层对输入进行调整，以便能够正确地与输出相加。
当残差块的输入和输出特征图的通道数不同时，直接相加是不可行的。为了在这种情况下实现跳跃连接，需要对输入进行适当的变换，使得它与输出具有相同的维度。通常的做法是使用1x1卷积层来调整输入的通道数，将channels_in转换成channels_out。这个1x1卷积层不会改变输入的高度和宽度，只改变通道数。如右图所示。
(图源:7.6. 残差网络（ResNet） — 动手学深度学习 2.0.0 documentation)
BuildingBlock和Bottleneck
Building Block和Bottleneck是两种不同类型的残差块结构，它们的主要区别在于内部的卷积层配置以及计算效率。
BuildingBlock
Building Block是最简单的残差块形式，通常用于较浅的ResNet模型中，比如ResNet-18和ResNet-34。它的基本结构包括：
- 两个3x3卷积层。
- 每个卷积层之后接一个批量归一化（Batch Normalization, BN）层。
- 第一个卷积层之后有一个ReLU激活函数。
- 跳跃连接（skip connection），将输入直接加到第二个卷积层的输出上。
- 最后一个ReLU激活函数位于跳跃连接之后。
(图源:基于MindSpore实现ResNet50中药分拣_哔哩哔哩_bilibili )
这样的结构简单且有效，但随着网络深度的增加，计算成本也会显著上升，因为每个3x3卷积层都会对大量的特征图进行操作。
Bottleneck
Bottleneck结构被设计用于更深的ResNet模型，例如ResNet-50、ResNet-101和ResNet-152。它通过引入瓶颈（bottleneck）机制来减少计算量，同时保持或增强模型性能。Bottleneck的基本结构如下：
- 一个1x1卷积层，用于减少通道数（降维），这被称为瓶颈。
- 一个3x3卷积层，这个卷积层在较少的通道上执行卷积运算。
- 另一个1x1卷积层，用于恢复原来的通道数（升维）。
- 每个卷积层后面都跟着BN层。
- 在第一个1x1卷积层和3x3卷积层之间有一个ReLU激活函数。
- 跳跃连接，将原始输入直接加到最后一个1x1卷积层的输出上。
- 最后一个ReLU激活函数位于跳跃连接之后。
(图源:基于MindSpore实现ResNet50中药分拣_哔哩哔哩_bilibili )
Bottleneck使得可以在不大幅增加计算负担的情况下堆叠更多的层，从而构建更深的网络。
各类ResNet模型架构如下所示：
(图源:基于MindSpore实现ResNet50中药分拣_哔哩哔哩_bilibili )
数据集
本案例使用“中药炮制饮片”数据集，该数据集由程度中医药大学提供，共包含中药炮制饮片的3个品种，分为：蒲黄、山楂、王不留行，每个品种有4个炮制状态：生品、不及、适中、太过。其中每类包含500张图片共12类，图片尺寸为4K，图片格式为jpg。
数据集可视化如下：
(图源:基于MindSpore实现ResNet50中药分拣_哔哩哔哩_bilibili )
基于MindSpore实现ResNet50中药分拣
数据下载及预处理
from download import download
import os
url = "https://mindspore-courses.obs.cn-north-4.myhuaweicloud.com/deep%20learning/AI%2BX/data/zhongyiyao.zip"
# 创建的是调试任务，url修改为数据集上传生成的url链接
if not os.path.exists("dataset"):
download(url, "dataset", kind="zip")因图片原尺寸为4K过大，因此需要将其Resize至指定尺寸
from PIL import Image
import numpy as np
data_dir = "dataset/zhongyiyao/zhongyiyao"
new_data_path = "dataset1/zhongyiyao"
if not os.path.exists(new_data_path):
for path in ['train','test']:
data_path = data_dir + "/" + path
classes = os.listdir(data_path)
for (i,class_name) in enumerate(classes):
floder_path = data_path+"/"+class_name
print(f"正在处理{floder_path}...")
for image_name in os.listdir(floder_path):
try:
image = Image.open(floder_path + "/" + image_name)
image = image.resize((1000,1000))
target_dir = new_data_path+"/"+path+"/"+class_name
if not os.path.exists(target_dir):
os.makedirs(target_dir)
if not os.path.exists(target_dir+"/"+image_name):
image.save(target_dir+"/"+image_name)
except:
pass 将数据集划分为训练集、测试集、验证集
from sklearn.model_selection import train_test_split
import shutil
def split_data(X, y, test_size=0.2, val_size=0.2, random_state=42):
"""
This function splits the data into training, validation, and test sets.
"""
# Split the data into training and test sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=test_size, random_state=random_state)
# Split the training data into training and validation sets
X_train, X_val, y_train, y_val = train_test_split(X_train, y_train, test_size=val_size/(1-test_size), random_state=random_state)
return X_train, X_val, X_test, y_train, y_val, y_test
data_dir = "dataset1/zhongyiyao"
floders = os.listdir(data_dir)
target = ['train','test','valid']
if set(floders) == set(target):
# 如果已经划分则跳过
pass
elif 'train' in floders:
# 如果已经划分了train，test，那么只需要从train里边划分出valid
floders = os.listdir(data_dir)
new_data_dir = os.path.join(data_dir,'train')
classes = os.listdir(new_data_dir)
if '.ipynb_checkpoints' in classes:
classes.remove('.ipynb_checkpoints')
imgs = []
labels = []
for (i,class_name) in enumerate(classes):
new_path = new_data_dir+"/"+class_name
for image_name in os.listdir(new_path):
imgs.append(image_name)
labels.append(class_name)
imgs_train,imgs_val,labels_train,labels_val = X_train, X_test, y_train, y_test = train_test_split(imgs, labels, test_size=0.2, random_state=42)
print("划分训练集图片数：",len(imgs_train))
print("划分验证集图片数：",len(imgs_val))
target_data_dir = os.path.join(data_dir,'valid')
if not os.path.exists(target_data_dir):
os.mkdir(target_data_dir)
for (img,label) in zip(imgs_val,labels_val):
source_path = os.path.join(data_dir,'train',label)
target_path = os.path.join(data_dir,'valid',label)
if not os.path.exists(target_path):
os.mkdir(target_path)
source_img = os.path.join(source_path,img)
target_img = os.path.join(target_path,img)
shutil.move(source_img,target_img)
else:
phones = os.listdir(data_dir)
imgs = []
labels = []
for phone in phones:
phone_data_dir = os.path.join(data_dir,phone)
yaowu_list = os.listdir(phone_data_dir)
for yaowu in yaowu_list:
yaowu_data_dir = os.path.join(phone_data_dir,yaowu)
chengdu_list = os.listdir(yaowu_data_dir)
for chengdu in chengdu_list:
chengdu_data_dir = os.path.join(yaowu_data_dir,chengdu)
for img in os.listdir(chengdu_data_dir):
imgs.append(img)
label = ' '.join([phone,yaowu,chengdu])
labels.append(label)
imgs_train, imgs_val, imgs_test, labels_train, labels_val, labels_test = split_data(imgs, labels, test_size=0.2, val_size=0.2, random_state=42)
img_label_tuple_list = [(imgs_train,labels_train),(imgs_val,labels_val),(imgs_test,labels_test)]
for (i,split) in enumerate(spilits):
target_data_dir = os.path.join(data_dir,split)
if not os.path.exists(target_data_dir):
os.mkdir(target_data_dir)
imgs_list,labels_list = img_label_tuple_list[i]
for (img,label) in zip(imgs_list,labels_list):
label_split = label.split(' ')
source_img = os.path.join(data_dir,label_split[0],label_split[1],label_split[2],img)
target_img_dir = os.path.join(target_data_dir,label_split[1]+"_"+label_split[2])
if not os.path.exists(target_img_dir):
os.mkdir(target_img_dir)
target_img = os.path.join(target_img_dir,img)
shutil.move(source_img,target_img)
定义数据加载方式
from mindspore.dataset import GeneratorDataset
import mindspore.dataset.vision as vision
import mindspore.dataset.transforms as transforms
from mindspore import dtype as mstype
# 注意没有使用Mindspore提供的ImageFloder进行加载，原因是调试任务中'.ipynb_checkpoints'缓存文件夹会被当作类文件夹进行识别，导致数据集加载错误
class Iterable:
def __init__(self,data_path):
self._data = []
self._label = []
self._error_list = []
if data_path.endswith(('JPG','jpg','png','PNG')):
# 用作推理，所以没有label
image = Image.open(data_path)
self._data.append(image)
self._label.append(0)
else:
classes = os.listdir(data_path)
if '.ipynb_checkpoints' in classes:
classes.remove('.ipynb_checkpoints')
for (i,class_name) in enumerate(classes):
new_path = data_path+"/"+class_name
for image_name in os.listdir(new_path):
try:
image = Image.open(new_path + "/" + image_name)
self._data.append(image)
self._label.append(i)
except:
pass
def __getitem__(self, index):
return self._data[index], self._label[index]
def __len__(self):
return len(self._data)
def get_error_list(self,):
return self._error_list
def create_dataset_zhongyao(dataset_dir,usage,resize,batch_size,workers):
data = Iterable(dataset_dir)
data_set = GeneratorDataset(data,column_names=['image','label'])
trans = []
if usage == "train":
trans += [
vision.RandomCrop(700, (4, 4, 4, 4)),
# 这里随机裁剪尺度可以设置
vision.RandomHorizontalFlip(prob=0.5)
]
trans += [
vision.Resize((resize,resize)),
vision.Rescale(1.0 / 255.0, 0.0),
vision.Normalize([0.4914, 0.4822, 0.4465], [0.2023, 0.1994, 0.2010]),
vision.HWC2CHW()
]
target_trans = transforms.TypeCast(mstype.int32)
# 数据映射操作
data_set = data_set.map(
operations=trans,
input_columns='image',
num_parallel_workers=workers)
data_set = data_set.map(
operations=target_trans,
input_columns='label',
num_parallel_workers=workers)
# 批量操作
data_set = data_set.batch(batch_size,drop_remainder=True)
return data_set加载数据
import mindspore as ms
import random
data_dir = "dataset1/zhongyiyao"
train_dir = data_dir+"/"+"train"
valid_dir = data_dir+"/"+"valid"
test_dir = data_dir+"/"+"test"
batch_size = 32 # 批量大小
image_size = 224 # 训练图像空间大小
workers = 4 # 并行线程个数
num_classes = 12 # 分类数量
# 设置随机种子，使得模型结果复现
seed = 42
ms.set_seed(seed)
np.random.seed(seed)
random.seed(seed)
dataset_train = create_dataset_zhongyao(dataset_dir=train_dir,
usage="train",
resize=image_size,
batch_size=batch_size,
workers=workers)
step_size_train = dataset_train.get_dataset_size()
dataset_val = create_dataset_zhongyao(dataset_dir=valid_dir,
usage="valid",
resize=image_size,
batch_size=batch_size,
workers=workers)
dataset_test = create_dataset_zhongyao(dataset_dir=test_dir,
usage="test",
resize=image_size,
batch_size=batch_size,
workers=workers)
step_size_val = dataset_val.get_dataset_size()
print(f'训练集数据：{dataset_train.get_dataset_size()*batch_size}\n')
print(f'验证集数据：{dataset_val.get_dataset_size()*batch_size}\n')
print(f'测试集数据：{dataset_test.get_dataset_size()*batch_size}\n')实现标签映射
#index_label的映射
index_label_dict = {}
classes = os.listdir(train_dir)
if '.ipynb_checkpoints' in classes:
classes.remove('.ipynb_checkpoints')
for i,label in enumerate(classes):
index_label_dict[i] = label
label2chin = {'ph_sp':'蒲黄-生品', 'ph_bj':'蒲黄-不及', 'ph_sz':'蒲黄-适中', 'ph_tg':'蒲黄-太过', 'sz_sp':'山楂-生品',
'sz_bj':'山楂-不及', 'sz_sz':'山楂-适中', 'sz_tg':'山楂-太过', 'wblx_sp':'王不留行-生品', 'wblx_bj':'王不留行-不及',
'wblx_sz':'王不留行-适中', 'wblx_tg':'王不留行-太过'}
index_label_dict定义ResNet50
残差块定义
class ResidualBlock(nn.Cell):
expansion = 4 # 最后一个卷积核的数量是第一个卷积核数量的4倍
def __init__(self, in_channel: int, out_channel: int,
stride: int = 1, down_sample: Optional[nn.Cell] = None) -> None:
super(ResidualBlock, self).__init__()
self.conv1 = nn.Conv2d(in_channel, out_channel,
kernel_size=1, weight_init=weight_init)
self.norm1 = nn.BatchNorm2d(out_channel)
self.conv2 = nn.Conv2d(out_channel, out_channel,
kernel_size=3, stride=stride,
weight_init=weight_init)
self.norm2 = nn.BatchNorm2d(out_channel)
self.conv3 = nn.Conv2d(out_channel, out_channel * self.expansion,
kernel_size=1, weight_init=weight_init)
self.norm3 = nn.BatchNorm2d(out_channel * self.expansion)
self.relu = nn.ReLU()
self.down_sample = down_sample
def construct(self, x):
identity = x # shortscuts分支
out = self.conv1(x) # 主分支第一层：1*1卷积层
out = self.norm1(out)
out = self.relu(out)
out = self.conv2(out) # 主分支第二层：3*3卷积层
out = self.norm2(out)
out = self.relu(out)
out = self.conv3(out) # 主分支第三层：1*1卷积层
out = self.norm3(out)
if self.down_sample is not None:
identity = self.down_sample(x)
out += identity # 输出为主分支与shortcuts之和
out = self.relu(out)
return out创建残差块的函数
def make_layer(last_out_channel, block: Type[Union[ResidualBlockBase, ResidualBlock]],
channel: int, block_nums: int, stride: int = 1):
down_sample = None # shortcuts分支
if stride != 1 or last_out_channel != channel * block.expansion:
down_sample = nn.SequentialCell([
nn.Conv2d(last_out_channel, channel * block.expansion,
kernel_size=1, stride=stride, weight_init=weight_init),
nn.BatchNorm2d(channel * block.expansion, gamma_init=gamma_init)
])
layers = []
layers.append(block(last_out_channel, channel, stride=stride, down_sample=down_sample))
in_channel = channel * block.expansion
# 堆叠残差网络
for _ in range(1, block_nums):
layers.append(block(in_channel, channel))
return nn.SequentialCell(layers)ResNet定义
from mindspore import load_checkpoint, load_param_into_net
from mindspore import ops
class ResNet(nn.Cell):
def __init__(self, block: Type[Union[ResidualBlockBase, ResidualBlock]],
layer_nums: List[int], num_classes: int, input_channel: int) -> None:
super(ResNet, self).__init__()
self.relu = nn.ReLU()
# 第一个卷积层，输入channel为3（彩色图像），输出channel为64
self.conv1 = nn.Conv2d(3, 64, kernel_size=7, stride=2, weight_init=weight_init)
self.norm = nn.BatchNorm2d(64)
# 最大池化层，缩小图片的尺寸
self.max_pool = nn.MaxPool2d(kernel_size=3, stride=2, pad_mode='same')
# 各个残差网络结构块定义
self.layer1 = make_layer(64, block, 64, layer_nums[0])
self.layer2 = make_layer(64 * block.expansion, block, 128, layer_nums[1], stride=2)
self.layer3 = make_layer(128 * block.expansion, block, 256, layer_nums[2], stride=2)
self.layer4 = make_layer(256 * block.expansion, block, 512, layer_nums[3], stride=2)
# 平均池化层
self.avg_pool = ops.ReduceMean(keep_dims=True)
# self.avg_pool = nn.AvgPool2d()
# flattern层
self.flatten = nn.Flatten()
# 全连接层
self.fc = nn.Dense(in_channels=input_channel, out_channels=num_classes)
def construct(self, x):
x = self.conv1(x)
x = self.norm(x)
x = self.relu(x)
x = self.max_pool(x)
x = self.layer1(x)
x = self.layer2(x)
x = self.layer3(x)
x = self.layer4(x)
x = self.avg_pool(x,(2,3))
x = self.flatten(x)
x = self.fc(x)
return x使用预训练的ResNet微调进行预测
def _resnet(model_url: str, block: Type[Union[ResidualBlockBase, ResidualBlock]],
layers: List[int], num_classes: int, pretrained: bool, pretrained_ckpt: str,
input_channel: int):
model = ResNet(block, layers, num_classes, input_channel)
if pretrained:
# 加载预训练模型
download(url=model_url, path=pretrained_ckpt)
param_dict = load_checkpoint(pretrained_ckpt)
load_param_into_net(model, param_dict)
return model
def resnet50(num_classes: int = 1000, pretrained: bool = False):
resnet50_url = "https://obs.dualstack.cn-north-4.myhuaweicloud.com/mindspore-website/notebook/models/application/resnet50_224_new.ckpt"
resnet50_ckpt = "./LoadPretrainedModel/resnet50_224_new.ckpt"
return _resnet(resnet50_url, ResidualBlock, [3, 4, 6, 3], num_classes,
pretrained, resnet50_ckpt, 2048)
network = resnet50(pretrained=True)
num_class = 12
# 全连接层输入层的大小
in_channel = network.fc.in_channels
fc = nn.Dense(in_channels=in_channel, out_channels=num_class)
# 重置全连接层
network.fc = fc
for param in network.get_parameters():
param.requires_grad = True
模型训练与推理
num_epochs = 50
# early stopping
patience = 5
lr = nn.cosine_decay_lr(min_lr=0.00001, max_lr=0.001, total_step=step_size_train * num_epochs,
step_per_epoch=step_size_train, decay_epoch=num_epochs)
opt = nn.Momentum(params=network.trainable_params(), learning_rate=lr, momentum=0.9)
loss_fn = nn.SoftmaxCrossEntropyWithLogits(sparse=True, reduction='mean')
model = ms.Model(network, loss_fn, opt, metrics={'acc'})
# 最佳模型存储路径
best_acc = 0
best_ckpt_dir = "./BestCheckpoint"
best_ckpt_path = "./BestCheckpoint/resnet50-best.ckpt"
def train_loop(model, dataset, loss_fn, optimizer):
# Define forward function
def forward_fn(data, label):
logits = model(data)
loss = loss_fn(logits, label)
return loss, logits
# Get gradient function
grad_fn = ms.ops.value_and_grad(forward_fn, None, optimizer.parameters, has_aux=True)
# Define function of one-step training
def train_step(data, label):
(loss, _), grads = grad_fn(data, label)
loss = ops.depend(loss, optimizer(grads))
return loss
size = dataset.get_dataset_size()
model.set_train()
for batch, (data, label) in enumerate(dataset.create_tuple_iterator()):
loss = train_step(data, label)
if batch % 100 == 0 or batch == step_size_train - 1:
loss, current = loss.asnumpy(), batch
print(f"loss: {loss:>7f} [{current:>3d}/{size:>3d}]")
from sklearn.metrics import classification_report
def test_loop(model, dataset, loss_fn):
num_batches = dataset.get_dataset_size()
model.set_train(False)
total, test_loss, correct = 0, 0, 0
y_true = []
y_pred = []
for data, label in dataset.create_tuple_iterator():
y_true.extend(label.asnumpy().tolist())
pred = model(data)
total += len(data)
test_loss += loss_fn(pred, label).asnumpy()
y_pred.extend(pred.argmax(1).asnumpy().tolist())
correct += (pred.argmax(1) == label).asnumpy().sum()
test_loss /= num_batches
correct /= total
print(f"Test: \n Accuracy: {(100*correct):>0.1f}%, Avg loss: {test_loss:>8f} \n")
print(classification_report(y_true,y_pred,target_names= list(index_label_dict.values()),digits=3))
return correct,test_loss
开始训练
no_improvement_count = 0
acc_list = []
loss_list = []
stop_epoch = num_epochs
for t in range(num_epochs):
print(f"Epoch {t+1}\n-------------------------------")
train_loop(network, dataset_train, loss_fn, opt)
acc,loss = test_loop(network, dataset_val, loss_fn)
acc_list.append(acc)
loss_list.append(loss)
if acc > best_acc:
best_acc = acc
if not os.path.exists(best_ckpt_dir):
os.mkdir(best_ckpt_dir)
ms.save_checkpoint(network, best_ckpt_path)
no_improvement_count = 0
else:
no_improvement_count += 1
if no_improvement_count > patience:
print('Early stopping triggered. Restoring best weights...')
stop_epoch = t
break
print("Done!")
模型推理
import matplotlib.pyplot as plt
num_class = 12 #
net = resnet50(num_class)
best_ckpt_path = 'BestCheckpoint/resnet50-best.ckpt'
# 加载模型参数
param_dict = ms.load_checkpoint(best_ckpt_path)
ms.load_param_into_net(net, param_dict)
model = ms.Model(net)
image_size = 224
workers = 1
def visualize_model(dataset_test):
# 加载验证集的数据进行验证
data = next(dataset_test.create_tuple_iterator())
# print(data)
images = data[0].asnumpy()
labels = data[1].asnumpy()
# 预测图像类别
output = model.predict(ms.Tensor(data[0]))
pred = np.argmax(output.asnumpy(), axis=1)
# 显示图像及图像的预测值
plt.figure(figsize=(10, 6))
for i in range(6):
plt.subplot(2, 3, i+1)
color = 'blue' if pred[i] == labels[i] else 'red'
plt.title('predict:{} actual:{}'.format(index_label_dict[pred[i]],index_label_dict[labels[i]]), color=color)
picture_show = np.transpose(images[i], (1, 2, 0))
mean = np.array([0.4914, 0.4822, 0.4465])
std = np.array([0.2023, 0.1994, 0.2010])
picture_show = std * picture_show + mean
picture_show = np.clip(picture_show, 0, 1)
plt.imshow(picture_show)
plt.axis('off')
plt.show()
visualize_model(dataset_val)
更多内容可参考MindSpore官方教程：
基于MindSpore实现ResNet50中药分拣_哔哩哔哩_bilibili
