Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shift Rethinking the Inception Architecture for Computer Vision
GoogleNet 网络结构的一种变形 - InceptionV2，改动主要有：
对比 网络结构之 GoogleNet(Inception V1)
- [1] - 5x5 卷积层被替换为两个连续的 3x3 卷积层. 网络的最大深度增加 9 个权重层. 参数量增加了大约 25%，计算量增加了大约 30%.
两个 3x3 卷积层作用可以代替一个 5x5 卷积层.
- [2] - 28x28 的 Inception 模块的数量由 2 增加到了 3.
- [3] - Inception 模块，Ave 和 Max Pooling 层均有用到. 参考表格.
- [4] - 两个 Inception 模块间不再使用 pooling 层；而在模块 3c 和 4e 中的 concatenation 前采用了 stride-2 conv/pooling 层.
- [5] - 网络结构的第一个卷积层采用了深度乘子为 8 的可分离卷积(separable convolution with depth multiplier 8)，减少了计算量，但训练时增加了内存消耗.
<h2>Tensorflow Slim 的 Inception V2 定义</h2>
"""
Inception V2 分类网络的定义.
"""
from future import absolute_import
from future import division
from future import print_function
import tensorflow as tf
from nets import inception_utils
slim = tf.contrib.slim
trunc_normal = lambda stddev: tf.truncated_normal_initializer(0.0, stddev)
def inception_v2_base(inputs,
final_endpoint='Mixed_5c',
min_depth=16,
depth_multiplier=1.0,
use_separable_conv=True,
data_format='NHWC',
scope=None):
"""
Inception V2 基础网络结构定义.
根据给定的输入和最终网络节点构建 Inception V2 网络.
可以构建表格中从输入到 inception(5b) 网络层的网络结构.
参数:
inputs: Tensor，尺寸为 [batch_size, height, width, channels].
final_endpoint: 指定网络定义结束的节点endpoint，即网络深度.
候选值：['Conv2d_1a_7x7', 'MaxPool_2a_3x3',
'Conv2d_2b_1x1', 'Conv2d_2c_3x3',
'MaxPool_3a_3x3', 'Mixed_3b', 'Mixed_3c',
'Mixed_4a', 'Mixed_4b', 'Mixed_4c', 'Mixed_4d', 'Mixed_4e',
'Mixed_5a', 'Mixed_5b', 'Mixed_5c'].
min_depth: 所有卷积 ops 的最小深度值(通道数，depth value (number of channels)).
当 depth_multiplier < 1 时，强制执行；
当 depth_multiplier >= 1 时，不是主动约束项.
depth_multiplier: 所有卷积 ops 深度(depth (number of channels))的浮点数乘子.
该值必须大于 0.
一般是将该值设为 (0, 1) 间的浮点数值，以减少参数量或模型的计算量.
use_separable_conv: 网络第一个卷积层Conv2d_1a_7x7，采用 separable convolution.
如果值为 False，则采用传统的 conv 层.
data_format: 激活值的数据格式 ('NHWC' or 'NCHW').
scope: 可选变量作用域 variable_scope.
返回值:
tensor_out: 对应到网络最终节点final_endpoint 的输出张量Tensor.
end_points: 外部使用的激活值集合，例如，summaries 和 losses.
Raises:
ValueError: if final_endpoint is not set to one of the predefined values,
or depth_multiplier <= 0
"""
# end_points 保存相关外用的激活值，例如 summaries 或 losses.
end_points = {}
# 用于寻找每一层的最薄的深度(depths，通道数).
if depth_multiplier <= 0:
raise ValueError('depth_multiplier is not greater than zero.')
depth = lambda d: max(int(d * depth_multiplier), min_depth)
if data_format != 'NHWC' and data_format != 'NCHW':
raise ValueError('data_format must be either NHWC or NCHW.')
if data_format == 'NCHW' and use_separable_conv:
raise ValueError(
'separable convolution only supports NHWC layout. NCHW data format can'
' only be used when use_separable_conv is False.'
)
concat_dim = 3 if data_format == 'NHWC' else 1
with tf.variable_scope(scope, 'InceptionV2', [inputs]):
with slim.arg_scope([slim.conv2d, slim.max_pool2d, slim.avg_pool2d],
stride=1,
padding='SAME',
data_format=data_format):
# 下面的注释中，假设网络的输入尺寸为 224x224.
# 实际上，网络的输入尺寸可以是任何大于 32x32 的尺寸.
# 224 x 224 x 3
end_point = 'Conv2d_1a_7x7'
if use_separable_conv: # 采用可分离卷积
# depthwise_multiplier here is different from depth_multiplier.
# depthwise_multiplier determines the output channels of the initial
# depthwise conv (see docs for tf.nn.separable_conv2d), while
# depth_multiplier controls the # channels of the subsequent 1x1
# convolution. Must have
# in_channels * depthwise_multipler <= out_channels
# so that the separable convolution is not overparameterized.
depthwise_multiplier = min(int(depth(64) / 3), 8)
net = slim.separable_conv2d(inputs, depth(64), [7, 7],
depth_multiplier=depthwise_multiplier,
stride=2,
padding='SAME',
weights_initializer=trunc_normal(1.0),
scope=end_point)
else: # 采用一般卷积
net = slim.conv2d(inputs, depth(64), [7, 7], stride=2,
weights_initializer=trunc_normal(1.0),
scope=end_point)
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 112 x 112 x 64
end_point = 'MaxPool_2a_3x3'
net = slim.max_pool2d(net, [3, 3], scope=end_point, stride=2)
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 56 x 56 x 64
end_point = 'Conv2d_2b_1x1'
net = slim.conv2d(net, depth(64), [1, 1], scope=end_point,
weights_initializer=trunc_normal(0.1))
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 56 x 56 x 64
end_point = 'Conv2d_2c_3x3'
net = slim.conv2d(net, depth(192), [3, 3], scope=end_point)
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 56 x 56 x 192
end_point = 'MaxPool_3a_3x3'
net = slim.max_pool2d(net, [3, 3], scope=end_point, stride=2)
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 28 x 28 x 192
# Inception module.
end_point = 'Mixed_3b'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(64), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(64), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(64), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(64), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(96), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(96), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(32), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 28 x 28 x 256
end_point = 'Mixed_3c'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(64), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(64), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(96), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(64), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(96), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(96), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(64), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 28 x 28 x 320
end_point = 'Mixed_4a'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(128), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_0 = slim.conv2d(branch_0, depth(160), [3, 3], stride=2, scope='Conv2d_1a_3x3')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(64), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(96), [3, 3], scope='Conv2d_0b_3x3')
branch_1 = slim.conv2d(branch_1, depth(96), [3, 3], stride=2, scope='Conv2d_1a_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.max_pool2d(net, [3, 3], stride=2, scope='MaxPool_1a_3x3')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 14 x 14 x 576
end_point = 'Mixed_4b'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(224), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(64), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(96), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(96), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(128), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(128), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(128), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 14 x 14 x 576
end_point = 'Mixed_4c'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(192), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(96), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(128), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(96), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(128), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(128), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(128), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 14 x 14 x 576
end_point = 'Mixed_4d'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(160), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(128), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(160), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(128), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(160), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(160), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(96), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 14 x 14 x 576
end_point = 'Mixed_4e'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(96), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(128), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(192), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(160), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(192), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(192), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(96), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 14 x 14 x 576
end_point = 'Mixed_5a'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(128), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_0 = slim.conv2d(branch_0, depth(192), [3, 3], stride=2, scope='Conv2d_1a_3x3')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(192), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(256), [3, 3], scope='Conv2d_0b_3x3')
branch_1 = slim.conv2d(branch_1, depth(256), [3, 3], stride=2, scope='Conv2d_1a_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.max_pool2d(net, [3, 3], stride=2, scope='MaxPool_1a_3x3')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 7 x 7 x 1024
end_point = 'Mixed_5b'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(352), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(192), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(320), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(160), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(224), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(224), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.avg_pool2d(net, [3, 3], scope='AvgPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(128), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
# 7 x 7 x 1024
end_point = 'Mixed_5c'
with tf.variable_scope(end_point):
with tf.variable_scope('Branch_0'):
branch_0 = slim.conv2d(net, depth(352), [1, 1], scope='Conv2d_0a_1x1')
with tf.variable_scope('Branch_1'):
branch_1 = slim.conv2d(net, depth(192), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_1 = slim.conv2d(branch_1, depth(320), [3, 3], scope='Conv2d_0b_3x3')
with tf.variable_scope('Branch_2'):
branch_2 = slim.conv2d(net, depth(192), [1, 1],
weights_initializer=trunc_normal(0.09),
scope='Conv2d_0a_1x1')
branch_2 = slim.conv2d(branch_2, depth(224), [3, 3], scope='Conv2d_0b_3x3')
branch_2 = slim.conv2d(branch_2, depth(224), [3, 3], scope='Conv2d_0c_3x3')
with tf.variable_scope('Branch_3'):
branch_3 = slim.max_pool2d(net, [3, 3], scope='MaxPool_0a_3x3')
branch_3 = slim.conv2d(branch_3, depth(128), [1, 1],
weights_initializer=trunc_normal(0.1),
scope='Conv2d_0b_1x1')
net = tf.concat(axis=concat_dim, values=[branch_0, branch_1, branch_2, branch_3])
end_points[end_point] = net
if end_point == final_endpoint: return net, end_points
raise ValueError('Unknown final endpoint %s' % final_endpoint)
def inception_v2(inputs,
num_classes=1000,
is_training=True,
dropout_keep_prob=0.8,
min_depth=16,
depth_multiplier=1.0,
prediction_fn=slim.softmax,
spatial_squeeze=True,
reuse=None,
scope='InceptionV2',
global_pool=False):
"""
Inception v2 分类模型.
网络训练的默认图片输入尺寸为 224x224.
参数:
inputs: Tensor，尺寸为 [batch_size, height, width, channels].
num_classes: 待预测的类别数.
如果 num_classes=0或None，则忽略 logits 层；返回 logits 层的输入特征(dropout 层前的网络层).
is_training: 是否是训练阶段.
dropout_keep_prob: 保留的激活值的比例.
min_depth: 所有卷积 ops 的最小深度值(通道数，depth value (number of channels)).
当 depth_multiplier < 1 时，强制执行；
当 depth_multiplier >= 1 时，不是主动约束项.
depth_multiplier: 所有卷积 ops 深度(depth (number of channels))的浮点数乘子.
该值必须大于 0.
一般是将该值设为 (0, 1) 间的浮点数值，以减少参数量或模型的计算量.
prediction_fn: 计算 logits 预测值输出的函数，如softmax.
spatial_squeeze: 如果是 True, logits 的 shape 是 [B, C]；
如果是 false，则 logits 的 shape 是 [B, 1, 1, C]；
其中，B 是 batch_size，C 是类别数.
reuse: 是否重用网络及网络的变量值.
如果需要重用，则必须给定重用的 'scope'.
scope: 可选变量作用域 variable_scope.
global_pool: 可选 boolean 值，选择是否在 logits 网络层前使用 avgpooling 层.
默认值是 fasle，则采用固定窗口的 pooling 层，将 inputs 降低到 1x1.
inputs 越大，则 outputs 越大.
如果值是 true, 则任何 inputs 尺寸都 pooled 到 1x1.
Returns:
net: Tensor，如果 num_classes 为非零值，则返回 logits(pre-softmax activations).
如果 num_classes 是 0 或 None，则返回 logits 网络层的 non-dropped-out 输入.
end_points: 字典，包含网络各层的激活值.
Raises:
ValueError: if final_endpoint is not set to one of the predefined values,
or depth_multiplier <= 0
"""
if depth_multiplier <= 0:
raise ValueError('depth_multiplier is not greater than zero.')
# Final pooling and prediction
with tf.variable_scope(scope, 'InceptionV2', [inputs], reuse=reuse) as scope:
with slim.arg_scope([slim.batch_norm, slim.dropout], is_training=is_training):
net, end_points = inception_v2_base(inputs, scope=scope,
min_depth=min_depth, depth_multiplier=depth_multiplier)
with tf.variable_scope('Logits'):
if global_pool:
# Global average pooling.
net = tf.reduce_mean(net, [1, 2], keep_dims=True, name='global_pool')
end_points['global_pool'] = net
else:
# Pooling with a fixed kernel size.
kernel_size = _reduced_kernel_size_for_small_input(net, [7, 7]) ##
net = slim.avg_pool2d(net, kernel_size, padding='VALID',
scope='AvgPool_1a_{}x{}'.format(*kernel_size))
end_points['AvgPool_1a'] = net
if not num_classes:
return net, end_points
# 1 x 1 x 1024
net = slim.dropout(net, keep_prob=dropout_keep_prob, scope='Dropout_1b')
logits = slim.conv2d(net, num_classes, [1, 1], activation_fn=None,
normalizer_fn=None, scope='Conv2d_1c_1x1')
if spatial_squeeze:
logits = tf.squeeze(logits, [1, 2], name='SpatialSqueeze')
end_points['Logits'] = logits
end_points['Predictions'] = prediction_fn(logits, scope='Predictions')
return logits, end_points
inception_v2.default_image_size = 224
def _reduced_kernel_size_for_small_input(input_tensor, kernel_size):
"""
定义核大小，用于对小尺寸的核大小的自动减小.
Define kernel size which is automatically reduced for small input.
创建 graph 时，如果输入图片的尺寸未知，则该函数假设输入图片尺寸足够大.
参数:
input_tensor: 输入 Tensor，尺寸为 [batch_size, height, width, channels].
kernel_size: desired kernel size of length 2: [kernel_height, kernel_width]
Returns:
a tensor with the kernel size.
TODO(jrru): Make this function work with unknown shapes. Theoretically, this
can be done with the code below. Problems are two-fold: (1) If the shape was
known, it will be lost. (2) inception.slim.ops._two_element_tuple cannot
handle tensors that define the kernel size.
shape = tf.shape(input_tensor)
return = tf.stack([tf.minimum(shape[1], kernel_size[0]),
tf.minimum(shape[2], kernel_size[1])])
"""
shape = input_tensor.get_shape().as_list()
if shape[1] is None or shape[2] is None:
kernel_size_out = kernel_size
else:
kernel_size_out = [min(shape[1], kernel_size[0]),
min(shape[2], kernel_size[1])]
return kernel_size_out
inception_v2_arg_scope = inception_utils.inception_arg_scope