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V-Net网络实现医学图像分割

时间:2020-05-31 10:42:32      阅读:100      评论:0      收藏:0      [点我收藏+]

标签:制作   导入   补充   目标   RKE   monitor   重要   创建   医学图像   

V-Net网络是图像分割中以3D结构存在的编解码网络模型

  V-Net网络在编码层引入残差结构。残差结构中,除了正常的卷积操作,还将卷积前的输入直接短路连接到输出端,这样网络可以学习到一个残差函数。学习残差可以加速收敛。编码网络用5×5×5卷积来提取图像特征,用步长为2,尺寸为2×2×2的卷积来代替最大池化。由于将模型公式化为残差网络,所以当我们降低它们的分辨率时,用卷积来加倍特征图数量。整个网络的激活函数为PReLu。右侧解码部分利用解码网络提取的特征并恢复图像空间分辨率,最后输出3D分割。最后的卷积层使用1×1×1卷积,得到与输入相同尺寸的输出结果。然后通过softmax层激活,生成目标和背景的概率图。在每一级解码层之后,用反卷积恢复空间分辨率,后接5×5×5卷积,并减半特征图数量。与编码网络一样,解码端也学习残差函数,不断地反卷积,来恢复位置信息,并且通过skip-connection将左侧编码部分各个阶段提取的特征传递到解码部分,以获取更多的图像细节信息,提高预测的准确性。skip-connection在图4-1中由水平连接示意性地表示。通过这种方式,补充了下采样丢失的信息,提高分割精度,同时skip-connection结构的引入还可以减少网络收敛时间。V-Net同样是是一种全卷积网络结构,因此对于输入3D图像没有二维尺寸要求。

技术图片

首先,制作训练数据

可以调整深度depth,图像尺寸image_size;可以选择制作某一位病人的训练数据,也可以加入循环,将所有病人切片制作数据集

 

 1 """
 2 本程序制作vnet数据集,同一dir中的11张切片作为一组输入
 3 服务器存储空间有限,一个dir一个dir进行制作,然后训练
 4 """
 5 import os
 6 import cv2 as cv
 7 import numpy as np
 8 
 9 
10 # 制作哪一个dir的数据
11 dir_num = 3
12 image_size = 400
13 depth = 11
14 
15 
16 train_png_path = "./data_dir_png/train"
17 label_png_path = "./data_dir_png/label"
18 train_64_input_path = "./vnet_" + str(depth) + "_1_input/train"
19 label_64_input_path = "./vnet_" + str(depth) + "_1_input/label"
20 if not os.path.isdir(train_64_input_path):
21     os.makedirs(train_64_input_path)
22 if not os.path.isdir(label_64_input_path):
23     os.makedirs(label_64_input_path)
24 
25 
26 train_dirs = os.listdir(train_png_path)
27 label_dirs = os.listdir(label_png_path)
28 train_dirs.sort(key=lambda x: int(x))
29 label_dirs.sort(key=lambda x: int(x))
30 # 选择需要制作数据的dir
31 dir_name = train_dirs[dir_num]
32 # train和label的dir地址
33 train_dir_path = os.path.join(train_png_path, dir_name)
34 label_dir_path = os.path.join(label_png_path, dir_name)
35 
36 train_pngs = os.listdir(train_dir_path)
37 train_pngs.sort(key=lambda x: int(x.split(".")[0]))
38 label_pngs = os.listdir(label_dir_path)
39 label_pngs.sort(key=lambda x: int(x.split(".")[0]))
40 
41 for i in range(len(train_pngs)):
42     train_npy = np.ndarray((depth, image_size, image_size, 1), dtype=np.uint8)
43     label_npy = np.ndarray((image_size, image_size, 1), dtype=np.uint8)
44     if (i + depth-1) < len(train_pngs):
45         label_img_path = os.path.join(label_dir_path, label_pngs[i+5])
46         label_img = cv.imread(label_img_path, 0)
47 
48         # cv.imshow("label", label_img)
49 
50         label_img = np.reshape(label_img, (image_size, image_size, 1))
51         label_npy = label_img
52         for j in range(depth):
53             index = i + j
54             train_img_path = os.path.join(train_dir_path, train_pngs[index])
55             train_img = cv.imread(train_img_path, 0)
56 
57             # cv.imshow("train", train_img)
58 
59             train_img = np.reshape(train_img, (image_size, image_size, 1))
60             train_npy[j] = train_img
61 
62             # cv.waitKey(0)
63             # cv.destroyAllWindows()
64 
65         train_input_path = os.path.join(train_64_input_path, str(dir_num))
66         label_input_path = os.path.join(label_64_input_path, str(dir_num))
67         if not os.path.isdir(train_input_path):
68             os.makedirs(train_input_path)
69         if not os.path.isdir(label_input_path):
70             os.makedirs(label_input_path)
71         print(train_npy.shape)
72         print(label_npy.shape)
73         np.save(train_input_path + "/" + str(i) + ".npy", train_npy)
74         np.save(label_input_path + "/" + str(i) + ".npy", label_npy)

 

然后,进行网络训练

 

  1 import keras
  2 from keras.models import *
  3 from keras.layers import Input, Conv3D, Deconvolution3D, Dropout, Concatenate, UpSampling3D
  4 from keras.optimizers import *
  5 from keras import layers
  6 from keras import backend as K
  7 
  8 from keras.callbacks import ModelCheckpoint
  9 from V_Net.vnet_3_3.fit_generator import get_path_list, get_train_batch
 10 import matplotlib.pyplot as plt
 11 
 12 train_batch_size = 1
 13 epoch = 1
 14 image_size = 512
 15 depth = 3
 16 
 17 data_train_path = "./data/train"
 18 data_label_path = "./data/label"
 19 train_path_list, label_path_list, count = get_path_list(data_train_path, data_label_path)
 20 
 21 
 22 # 写一个LossHistory类,保存loss和acc
 23 class LossHistory(keras.callbacks.Callback):
 24    def on_train_begin(self, logs={}):
 25        self.losses = {batch: [], epoch: []}
 26        self.accuracy = {batch: [], epoch: []}
 27        self.val_loss = {batch: [], epoch: []}
 28        self.val_acc = {batch: [], epoch: []}
 29 
 30    def on_batch_end(self, batch, logs={}):
 31        self.losses[batch].append(logs.get(loss))
 32        self.accuracy[batch].append(logs.get(dice_coef))
 33        self.val_loss[batch].append(logs.get(val_loss))
 34        self.val_acc[batch].append(logs.get(val_acc))
 35 
 36    def on_epoch_end(self, batch, logs={}):
 37        self.losses[epoch].append(logs.get(loss))
 38        self.accuracy[epoch].append(logs.get(dice_coef))
 39        self.val_loss[epoch].append(logs.get(val_loss))
 40        self.val_acc[epoch].append(logs.get(val_acc))
 41 
 42    def loss_plot(self, loss_type):
 43        iters = range(len(self.losses[loss_type]))
 44        plt.figure()
 45        # acc
 46        plt.plot(iters, self.accuracy[loss_type], r, label=train dice)
 47        # loss
 48        plt.plot(iters, self.losses[loss_type], g, label=train loss)
 49        if loss_type == epoch:
 50            # val_acc
 51            plt.plot(iters, self.val_acc[loss_type], b, label=val acc)
 52            # val_loss
 53            plt.plot(iters, self.val_loss[loss_type], k, label=val loss)
 54        plt.grid(True)
 55        plt.xlabel(loss_type)
 56        plt.ylabel(dice-loss)
 57        plt.legend(loc="best")
 58        plt.show()
 59 
 60 
 61 def dice_coef(y_true, y_pred):
 62     smooth = 1.
 63     y_true_f = K.flatten(y_true)
 64     y_pred_f = K.flatten(y_pred)
 65     intersection = K.sum(y_true_f * y_pred_f)
 66     return (2. * intersection + smooth) / (K.sum(y_true_f * y_true_f) + K.sum(y_pred_f * y_pred_f) + smooth)
 67 
 68 
 69 def dice_coef_loss(y_true, y_pred):
 70     return 1. - dice_coef(y_true, y_pred)
 71 
 72 
 73 def mycrossentropy(y_true, y_pred, e=0.1):
 74     nb_classes = 10
 75     loss1 = K.categorical_crossentropy(y_true, y_pred)
 76     loss2 = K.categorical_crossentropy(K.ones_like(y_pred) / nb_classes, y_pred)
 77     return (1 - e) * loss1 + e * loss2
 78 
 79 
 80 class myVnet(object):
 81     def __init__(self, img_depth=depth, img_rows=image_size, img_cols=image_size, img_channel=1, drop=0.5):
 82         self.img_depth = img_depth
 83         self.img_rows = img_rows
 84         self.img_cols = img_cols
 85         self.img_channel = img_channel
 86         self.drop = drop
 87 
 88     def BN_operation(self, input):
 89         output = keras.layers.normalization.BatchNormalization(axis=-1, momentum=0.99, epsilon=0.001, center=True,
 90                                                                scale=True,
 91                                                                beta_initializer=zeros, gamma_initializer=ones,
 92                                                                moving_mean_initializer=zeros,
 93                                                                moving_variance_initializer=ones,
 94                                                                beta_regularizer=None,
 95                                                                gamma_regularizer=None, beta_constraint=None,
 96                                                                gamma_constraint=None)(input)
 97         return output
 98 
 99     def encode_layer(self, kernel_num, kernel_size, input):
100         # 第一次卷积
101         conv1 = Conv3D(kernel_num, kernel_size, activation=relu, padding=same,
102                        kernel_initializer=he_normal)(input)
103         conv1 = self.BN_operation(conv1)
104         conv1 = Dropout(self.drop)(conv1)
105         # 第二次卷积
106         conv2 = Conv3D(kernel_num, kernel_size, activation=relu, padding=same,
107                        kernel_initializer=he_normal)(conv1)
108         conv2 = self.BN_operation(conv2)
109         conv2 = Dropout(self.drop)(conv2)
110         # 残差
111         res = layers.add([conv1, conv2])
112         return res
113 
114     def down_operation(self, kernel_num, kernel_size, input):
115         down = Conv3D(kernel_num, kernel_size, strides=[1, 2, 2], activation=relu, padding=same,
116                       kernel_initializer=he_normal)(input)
117         down = self.BN_operation(down)
118         down = Dropout(self.drop)(down)
119         return down
120 
121     def decode_layer(self, kernel_num, kernel_size, input, code_layer):
122         # deconv = Deconvolution3D(kernel_num, kernel_size, strides=(1, 2, 2), activation=‘relu‘, padding=‘same‘,
123         #                          kernel_initializer=‘he_normal‘)(input)
124         deconv = Conv3D(kernel_num, kernel_size, activation=relu, padding=same, kernel_initializer=he_normal)(
125                  UpSampling3D(size=(1, 2, 2))(input))
126 
127         merge = Concatenate(axis=4)([deconv, code_layer])
128         conv = Conv3D(kernel_num, kernel_size, activation=relu, padding=same,
129                       kernel_initializer=he_normal)(merge)
130         conv = self.BN_operation(conv)
131         conv = Dropout(self.drop)(conv)
132 
133         res = layers.add([deconv, conv])
134         return res
135 
136     # V-Net网络
137     def get_vnet(self):
138         inputs = Input((self.img_depth, self.img_rows, self.img_cols, self.img_channel))
139 
140         # 卷积层1
141         conv1 = self.encode_layer(16, [depth, 3, 3], inputs)
142         # 下采样1
143         down1 = self.down_operation(32, [depth, 3, 3], conv1)
144 
145         # 卷积层2
146         conv2 = self.encode_layer(32, [depth, 3, 3], down1)
147         # 下采样2
148         down2 = self.down_operation(64, [depth, 3, 3], conv2)
149 
150         # 卷积层3
151         conv3 = self.encode_layer(64, [depth, 3, 3], down2)
152         # 下采样3
153         down3 = self.down_operation(128, [depth, 3, 3], conv3)
154 
155         # 卷积层4
156         conv4 = self.encode_layer(128, [depth, 3, 3], down3)
157         # 下采样4
158         down4 = self.down_operation(256, [depth, 3, 3], conv4)
159 
160         # 卷积层5
161         conv5 = self.encode_layer(256, [depth, 3, 3], down4)
162 
163         # 反卷积6
164         deconv6 = self.decode_layer(128, [depth, 3, 3], conv5, conv4)
165 
166         # 反卷积7
167         deconv7 = self.decode_layer(64, [depth, 3, 3], deconv6, conv3)
168 
169         # 反卷积8
170         deconv8 = self.decode_layer(32, [depth, 3, 3], deconv7, conv2)
171 
172         # 反卷积9
173         deconv9 = self.decode_layer(16, [depth, 3, 3], deconv8, conv1)
174         conv9 = Conv3D(8, [depth, 3, 3], activation=relu, padding=same,
175                        kernel_initializer=he_normal)(deconv9)
176         conv9 = Conv3D(4, [depth, 3, 3], activation=relu, padding=same,
177                        kernel_initializer=he_normal)(conv9)
178         conv9 = Conv3D(2, [depth, 3, 3], activation=relu, padding=same,
179                        kernel_initializer=he_normal)(conv9)
180 
181         conv10 = Conv3D(1, [1, 1, 1], activation=sigmoid)(conv9)
182 
183         model = Model(inputs=inputs, outputs=conv10)
184 
185         # 在这里可以自定义损失函数loss和准确率函数accuracy
186         # model.compile(optimizer=Adam(lr=1e-4), loss=‘binary_crossentropy‘, metrics=[‘accuracy‘])
187         model.compile(optimizer=Adam(lr=1e-4), loss=binary_crossentropy, metrics=[accuracy,
188                                                                                     dice_coef])
189         print(model compile)
190         return model
191 
192     def train(self):
193         print("loading data")
194         print("loading data done")
195 
196         model = self.get_vnet()
197         print("got vnet")
198 
199         # 保存的是模型和权重
200         model_checkpoint = ModelCheckpoint(../model/vnet_liver.hdf5, monitor=loss,
201                                            verbose=1, save_best_only=True)
202         print(Fitting model...)
203 
204         # 创建一个实例history
205         history = LossHistory()
206         # 在callbacks中加入history最后才能绘制收敛曲线
207         model.fit_generator(
208             generator=get_train_batch(train_path_list, label_path_list, train_batch_size, depth, image_size, image_size),
209             epochs=epoch, verbose=1,
210             steps_per_epoch=count//train_batch_size,
211             callbacks=[model_checkpoint, history],
212             workers=1)
213         # 绘制acc-loss曲线
214         history.loss_plot(batch)
215         plt.savefig(vnet_liver_dice_loss_curve.png)
216 
217 
218 if __name__ == __main__:
219     myvnet = myVnet()
220     myvnet.train()

 

导入数据程序 

 

  1 import numpy as np
  2 import cv2 as cv
  3 import os
  4 
  5 data_train_path = "../../Vnet_tf/V_Net_data/train"
  6 data_label_path = "../../Vnet_tf/V_Net_data/label"
  7 
  8 
  9 def get_path_list(data_train_path, data_label_path):
 10     dirs = os.listdir(data_train_path)
 11     dirs.sort(key=lambda x: int(x))
 12     count = 0
 13     for dir in dirs:
 14         dir_path = os.path.join(data_train_path, dir)
 15         count += len(os.listdir(dir_path))
 16     print("共有{}组训练数据".format(count))
 17 
 18     train_path_list = []
 19     label_path_list = []
 20     for dir in dirs:
 21         train_dir_path = os.path.join(data_train_path, dir)
 22         label_dir_path = os.path.join(data_label_path, dir)
 23         trains = os.listdir(train_dir_path)
 24         labels = os.listdir(label_dir_path)
 25         trains.sort(key=lambda x: int(x.split(".")[0]))
 26         labels.sort(key=lambda x: int(x.split(".")[0]))
 27         for name in trains:
 28             train_path = os.path.join(train_dir_path, name)
 29             label_path = os.path.join(label_dir_path, name)
 30 
 31             train_path_list.append(train_path)
 32             label_path_list.append(label_path)
 33 
 34     return train_path_list, label_path_list, count
 35 
 36 
 37 def get_train_img(paths, img_d, img_rows, img_cols):
 38     """
 39     参数:
 40         paths:要读取的图片路径列表
 41         img_rows:图片行
 42         img_cols:图片列
 43         color_type:图片颜色通道
 44     返回:
 45         imgs: 图片数组
 46     """
 47     # Load as grayscale
 48     datas = []
 49     for path in paths:
 50         data = np.load(path)
 51         # Reduce size
 52         resized = np.reshape(data, (img_d, img_rows, img_cols, 1))
 53         resized = resized.astype(float32)
 54         resized /= 255
 55         mean = resized.mean(axis=0)
 56         resized -= mean
 57         datas.append(resized)
 58     datas = np.array(datas)
 59     return datas
 60 
 61 
 62 def get_label_img(paths, img_d, img_rows, img_cols):
 63     """
 64     参数:
 65         paths:要读取的图片路径列表
 66         img_rows:图片行
 67         img_cols:图片列
 68         color_type:图片颜色通道
 69     返回:
 70         imgs: 图片数组
 71     """
 72     # Load as grayscale
 73     datas = []
 74     for path in paths:
 75         data = np.load(path)
 76         # Reduce size
 77         resized = np.reshape(data, (img_d, img_cols, img_rows, 1))
 78         resized = resized.astype(float32)
 79         resized /= 255
 80         datas.append(resized)
 81     datas = np.array(datas)
 82     return datas
 83 
 84 
 85 def get_train_batch(train, label, batch_size, img_d, img_w, img_h):
 86     """
 87     参数:
 88         X_train:所有图片路径列表
 89         y_train: 所有图片对应的标签列表
 90         batch_size:批次
 91         img_w:图片宽
 92         img_h:图片高
 93         color_type:图片类型
 94         is_argumentation:是否需要数据增强
 95     返回:
 96         一个generator,x: 获取的批次图片 y: 获取的图片对应的标签
 97     """
 98     while 1:
 99         for i in range(0, len(train), batch_size):
100             x = get_train_img(train[i:i+batch_size], img_d, img_w, img_h)
101             y = get_label_img(label[i:i+batch_size], img_d, img_w, img_h)
102             # 最重要的就是这个yield,它代表返回,返回以后循环还是会继续,然后再返回。就比如有一个机器一直在作累加运算,但是会把每次累加中间结果告诉你一样,直到把所有数加完
103             yield(np.array(x), np.array(y))
104 
105 
106 if __name__ == "__main__":
107     train_path_list, label_path_list, count = get_path_list(data_train_path, data_label_path)
108     print(train_path_list)

 

最后,测试模型

 

使用训练集生成程序来生成测试集;测试网络;评估模型

 

V-Net网络实现医学图像分割

标签:制作   导入   补充   目标   RKE   monitor   重要   创建   医学图像   

原文地址:https://www.cnblogs.com/jinyiyexingzc/p/12996396.html

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