我正在制作图像去噪模型并使用 ImageDataGenerator.flow_from_directory 加载数据集。它由两个文件夹构成，一个包含嘈杂的输入图像，另一个包含相应的干净图像。我希望生成器将第一个文件夹中的图像用作输入，将另一个文件夹中的图像用作“标签”/ground truth。
使用我现在使用的方法，两个文件夹中的所有图像都被视为输入，文件夹名称作为标签。我可以通过选择特定批次来手动提取图像并对其进行训练，但这很不方便，而且可能不打算以这种方式使用。
这样做的正确方法是什么？可能有此功能，但我找不到。
答案 0 :(得分：0)
有类似的问题。发现有必要创建一个自定义生成器来将图像输入到 model.fit 中。代码（相当长）发布在下面。
import os
import pandas as pd
import numpy as np
import glob
import cv2
from sklearn.model_selection import train_test_split
def create_df(image_dir, label_dir, shuffle=True):
path=image_dir + '/**/*'
image_file_paths=glob.glob(path,recursive=True)
path=label_dir + '/**/*'
label_file_paths=glob.glob(path,recursive=True)
# run a check and make sure filename without extensions match
df=pd.DataFrame({'image': image_file_paths, 'label':label_file_paths}).astype(str)
if shuffle:
df=df.sample(frac=1.0, replace=False, weights=None, random_state=123, axis=0).reset_index(drop=True)
return df
class jpgen():
batch_index=0 #tracks the number of batches generated
def __init__(self, df, train_split=None, test_split=None):
self.train_split=train_split # float between 0 and 1 indicating the percentage of images to use for training
self.test_split=test_split
self.df=df.copy() # create a copy of the data frame
if self.train_split != None: # split the df to create a training df
self.train_df, dummy_df=train_test_split(self.df, train_size=self.train_split, shuffle=False)
if self.test_split !=None: # create as test set and a validation set
t_split=self.test_split/(1.0-self.train_split)
self.test_df, self.valid_df=train_test_split(dummy_df, train_size=t_split, shuffle=False)
self.valid_gen_len=len(self.valid_df['image'].unique())# create var to return no of samples in valid generator
self.valid_gen_filenames=list(self.valid_df['image'])# create list ofjpg file names in valid generator
else: self.test_df=dummy_df
self.test_gen_len=len(self.test_df['image'].unique())#create var to return no of test samples
self.test_gen_filenames=list(self.test_df['image']) # create list to return jpg file paths in test_gen
else:
self.train_df=self.df
self.tr_gen_len=len(self.train_df['image'].unique()) # crete variable to return no of samples in train generator
def flow(self, batch_size=32, image_shape=None,rescale=None,shuffle=True, subset=None ):
# flows batches of jpg images and png masks to model.fit
self.batch_size=batch_size
self.image_shape=image_shape
self.shuffle=shuffle
self.subset=subset
self.rescale=rescale
image_batch_list=[] # initialize list to hold a batch of jpg images
label_batch_list=[] # initialize list to hold batches of png masks
if self.subset=='training' or self.train_split ==None:
op_df=self.train_df
elif self.subset=='test':
op_df=self.test_df
else:
op_df=self.valid_df
if self.shuffle : # shuffle the op_df then rest the index
op_df=op_df.sample(frac=1.0, replace=False, weights=None, random_state=123, axis=0).reset_index(drop=True)
#op_df will be either train, test or valid depending on subset
# develop the batch of data
while True:
label_batch_list=[]
image_batch_list=[]
start=jpgen.batch_index * self.batch_size # set start value of iteration
end=start + self.batch_size # set end value of iteration to yield 1 batch of data of length batch_size
sample_count=len(op_df['image'])
for i in range(start, end): # iterate over one batch size of data
j=i % sample_count # used to roll the images back to the front if the end is reached
k=j % self.batch_size
path_to_image= op_df.iloc[j]['image']
path_to_label= op_df.iloc[j] ['label']
label_image=cv2.imread(path_to_label, -1) # read unchanged to preserve 4 th channel print (png_image.)
label_image= cv2.cvtColor(label_image, cv2.COLOR_BGR2RGB)
image_image=cv2.imread(path_to_image)
image_image= cv2.cvtColor(image_image, cv2.COLOR_BGR2RGB)
label_image=cv2.resize(label_image, self.image_shape)
image_image=cv2.resize(image_image, self.image_shape )
if rescale !=None:
label_image=label_image * self.rescale
image_image=image_image * self.rescale
label_batch_list.append(label_image)
image_batch_list.append(image_image)
image_array=np.array(image_batch_list)
label_array=np.array(label_batch_list)
jpgen.batch_index +=1
yield (image_array, label_array)
下面的代码展示了如何使用上面的函数为model.fit制作生成器
image_dir=r'C:\Temp\gen_test\images'# directory with clean images
label_dir=r'C:\Temp\gen_test\labels' # directory with noisy images file names same as filenames in clean dir
shuffle=False # if True shuffles the dataframe
df=create_df(image_dir, label_dir ,shuffle) # create a dataframe with columns 'images' , 'labels'
# where labels are the noisy images
train_split=.8 # use 80% of files for training
test_split=.1 # use 10% for test, automatically sets validation split at 1-train_split-test_split
batch_size=32 # set batch_size
height=224 # set image height for generator output images and labels
width=224 # set image width for generator output images and labels
channels=3 # set number of channel in images
image_shape=(height, width)
rescale=1/255 # set value to rescale image pixels
gen=jpgen(df, train_split=train_split, test_split=test_split) # create instance of generator class
tr_gen_len=gen.tr_gen_len
test_gen_len= gen.test_gen_len
valid_gen_len=gen.valid_gen_len
test_filenames=gen.test_gen_filenames # names of test file paths used for training
train_steps=tr_gen_len//batch_size # use this value in for steps_per_epoch in model.fit
valid_steps=valid_gen_len//batch_size # use this value for validation_steps in model.fit
test_steps=test_gen_len//batch_size # use this value for steps in model.predict
# instantiate generators
train_gen=gen.flow(batch_size=batch_size, image_shape=image_shape, rescale=rescale, shuffle=False, subset='training')
valid_gen=gen.flow(batch_size=batch_size, image_shape=image_shape, rescale=rescale, shuffle=False, subset='valid')
test_gen=gen.flow(batch_size=batch_size, image_shape=image_shape, rescale=rescale, shuffle=False, subset='test')
构建模型然后使用
history=model.fit(train_gen, epochs=epochs, steps_per_epoch=train_steps,validation_data=valid_gen,
validation_steps=valid_steps, verbose=1, shuffle=True)
predictions=model.predict(test_gen, steps=test_steps)