我正在尝试基于GTSRB数据集（以下给出的链接）创建CNN模型，但遇到以下错误：
当我设置input_shape = input_shape =（3，IMG_SIZE，IMG_SIZE）时，出现此错误：
ValueError：检查输入时出错：预期的conv2d_34_input为 有4个维度，但数组的形状为（9030，1）
研究问题时，我发现一个解决方案可能是将batch_size作为参数传递，当我尝试这样做时，出现此错误：
ValueError：输入0与层conv2d_40不兼容：预期 ndim = 4，找到的ndim = 5
当我尝试重塑training_images时，出现此错误：
ValueError：无法将大小为9030的数组重塑为形状（48,48,3）
代码段： 加载训练数据集：
import csv
# Training dataset
def readTrafficSignsTrain(rootpath):
'''Reads traffic sign data for German Traffic Sign Recognition Benchmark.
Arguments: path to the traffic sign data, for example './GTSRB/Training'
Returns: list of images, list of corresponding labels'''
images = [] # images
labels = [] # corresponding labels
# loop over all 42 classes
for c in range(0,43):
# prefix = rootpath + '/' + format(c, '05d') + '/' # subdirectory for class
# annFile = open(prefix + 'GT-'+ format(c, '05d') + '.csv') # annotations file
prefix = rootpath + '/00000' + '/'
annFile = open(prefix + 'GT-00000' + '.csv')
annReader = csv.reader(annFile, delimiter=';') # csv parser for annotations file
next(annReader, None) # skip header
# loop over all images in current annotations file
for row in annReader:
images.append(plt.imread(prefix + row[0])) # the 1st column is the filename
labels.append(row[7]) # the 8th column is the label
annFile.close()
return images, labels
training_images, training_labels = readTrafficSignsTrain('./GTSRB/Training')
这是一个问题，例如图像的形状不一样
print(len(training_images))
print(len(training_labels))
print()
print(training_images[0].shape)
print(training_images[20].shape)
print(training_images[200].shape)
print(training_images[2000].shape)
输出
9030 9030
（30，29，3）（54，57，3）（69，63，3）（52，51，3）
图层设置（从下面链接的Keras文档复制和粘贴）：
IMG_SIZE = 48
NUM_CLASSES = 43
K.set_image_data_format('channels_first')
batch_size = 32
def cnn_model():
model = Sequential()
model.add(Conv2D(32, (3, 3), padding='same',
input_shape=(3, IMG_SIZE, IMG_SIZE),
activation='relu',
data_format="channels_first"))
model.add(Conv2D(32, (3, 3), activation='relu'))
model.add(MaxPooling2D(pool_size=(2, 2), data_format="channels_first"))
model.add(Dropout(0.2))
model.add(Conv2D(64, (3, 3), padding='same',
activation='relu'))
model.add(Conv2D(64, (3, 3), activation='relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Dropout(0.2))
model.add(Conv2D(128, (3, 3), padding='same',
activation='relu'))
model.add(Conv2D(128, (3, 3), activation='relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Dropout(0.2))
model.add(Flatten())
model.add(Dense(512, activation='relu'))
model.add(Dropout(0.5))
model.add(Dense(NUM_CLASSES, activation='softmax'))
return model
model = cnn_model()
训练模型（暂时暂时为model.fit
import numpy
trim = numpy.array(training_images)
trlb = numpy.array(training_labels)
print(training_images[0].shape)
print(trim.shape)
trim - trim.reshape(48, 48, 3)
model.fit(trim, trlb, epochs = 30, batch_size = 32)
输出
ValueError：无法将大小为9030的数组重塑为形状（48,48,3）
当我移除重塑形状
ValueError：检查输入时出错：预期的conv2d_41_input为 有4个维度，但数组的形状为（9030，1）
当我改用它时
model.fit(training_images, training_labels, epochs = 30, batch_size = 32)
输出
> ValueError: Error when checking model input: the list of Numpy arrays
> that you are passing to your model is not the size the model expected.
> Expected to see 1 array(s), but instead got the following list of 9030
> arrays: [array([[[ 75, 78, 80],
> [ 74, 76, 78],
> [ 86, 87, 84],
> ...,
> [ 68, 75, 75],
> [ 65, 69, 68],
> [ 66, 67, 66]],
>
> [[ 83, 84, 86],
> [...
所以，如果我这样做（不确定原因）
for i in range(len(training_images)):
model.fit(training_images[i], training_labels[i], epochs = 30, batch_size = 32)
我明白了
ValueError：检查输入时出错：预期的conv2d_41_input为 有4个维度，但数组的形状为（30，29，3）
那就是
input_shape=(3, IMG_SIZE, IMG_SIZE)
如果我做
input_shape=(batch_size, 3, IMG_SIZE, IMG_SIZE)
我知道
ValueError：输入0与层conv2d_47不兼容：预期 ndim = 4，找到的ndim = 5
model.summary（）的输出
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
conv2d_34 (Conv2D) (None, 32, 48, 48) 896
_________________________________________________________________
conv2d_35 (Conv2D) (None, 32, 46, 46) 9248
_________________________________________________________________
max_pooling2d_14 (MaxPooling (None, 32, 23, 23) 0
_________________________________________________________________
dropout_14 (Dropout) (None, 32, 23, 23) 0
_________________________________________________________________
conv2d_36 (Conv2D) (None, 64, 23, 23) 18496
_________________________________________________________________
conv2d_37 (Conv2D) (None, 64, 21, 21) 36928
_________________________________________________________________
max_pooling2d_15 (MaxPooling (None, 64, 10, 10) 0
_________________________________________________________________
dropout_15 (Dropout) (None, 64, 10, 10) 0
_________________________________________________________________
conv2d_38 (Conv2D) (None, 128, 10, 10) 73856
_________________________________________________________________
conv2d_39 (Conv2D) (None, 128, 8, 8) 147584
_________________________________________________________________
max_pooling2d_16 (MaxPooling (None, 128, 4, 4) 0
_________________________________________________________________
dropout_16 (Dropout) (None, 128, 4, 4) 0
_________________________________________________________________
flatten_4 (Flatten) (None, 2048) 0
_________________________________________________________________
dense_10 (Dense) (None, 512) 1049088
_________________________________________________________________
dropout_17 (Dropout) (None, 512) 0
_________________________________________________________________
dense_11 (Dense) (None, 43) 22059
=================================================================
Total params: 1,358,155
Trainable params: 1,358,155
Non-trainable params: 0
_________________________________________________________________
None
如果任何人都可以提供帮助，那将不胜感激。
链接 GTSRB：http://benchmark.ini.rub.de/?section=gtsrb&subsection=news 我从以下网址获得了Keras文档：https://chsasank.github.io/keras-tutorial.html
有关github上完整项目的链接：https://github.com/PavlySz/TSR-Project
谢谢！
答案 0 :(得分：0)
您不能将np.array整形为维数不允许的形状。这是您可以做的
import numpy as np
img_arr = np.array([np.ones((30, 29, 3)),
np.ones((54, 57, 3)),
np.ones((69, 63, 3)),
np.ones((52, 51, 3))])
print(img_arr.shape)
import cv2
img_arr_conv = np.array([cv2.resize(img, dsize=(48, 48)) for img in img_arr])
print(img_arr_conv.shape)
>>>(4,)
>>>(4, 48, 48, 3)
之所以得到ValueError: cannot reshape array of size 9030 into shape (48,48,3)，是因为如果元素的大小都不同，则numpy无法推断数组的尺寸，并且无法重新调整尺寸不允许的数组形状。 ValueError: Error when checking input: expected conv2d_41_input to have 4 dimensions, but got array with shape (9030, 1)的情况也是如此。 Numpy只知道数组中有9030个元素。它只能做些什么，因为元素的所有尺寸都不同。
例子
img_arr_bad = np.array([np.ones((30, 29, 3)),
np.ones((54, 57, 3)),
np.ones((69, 63, 3)),
np.ones((52, 51, 3))])
img_arr_good = np.array([np.ones((48, 48, 3)),
np.ones((48, 48, 3)),
np.ones((48, 48, 3)),
np.ones((48, 48, 3))])
print(img_arr_bad.shape)
print(img_arr_good.shape)
>>>(4,)
>>>(4, 48, 48, 3)
希望这会有所帮助