本文直接从Inception v3的代码实现入手，分析其中值得借鉴的思想
首先要知道一个slim的组件，可以给参数自动赋值，可以省去很多操作
def inception_arg_scope(weight_decay=0.00004, use_batch_norm=True, batch_norm_decay=0.9997, batch_norm_epsilon=0.001): """Defines the default arg scope for inception models. Args: weight_decay: 设置L2正则 use_batch_norm: 设置是否使用batch normalization batch_norm_decay: BN的衰减系数 batch_norm_epsilon: 为了避免除数为0加的一个小型浮点数 Returns: An `arg_scope` to use for the inception models. """ batch_norm_params = { 'decay': batch_norm_decay, 'epsilon': batch_norm_epsilon, 'updates_collections': tf.GraphKeys.UPDATE_OPS, } if use_batch_norm: normalizer_fn = slim.batch_norm normalizer_params = batch_norm_params else: normalizer_fn = None normalizer_params = {} # 下面这句会对conv2d和全连接层这两个函数的weights_regularizer参数自动赋值为 with slim.arg_scope([slim.conv2d, slim.fully_connected], weights_regularizer=slim.l2_regularizer(weight_decay)): #接下来再嵌套一个slim.arg_scope,对conv2d的权重、激活函数、正则化函数及其参数自动赋值后将其返回 with slim.arg_scope( [slim.conv2d], weights_initializer=slim.variance_scaling_initializer(), activation_fn=tf.nn.relu, normalizer_fn=normalizer_fn, normalizer_params=normalizer_params) as sc: return sc该函数的的作用就是事先定义好conv2d中的各种参数，之后再定义卷积层就会非常方便。trunc_normal = lambda stddev: tf.truncated_normal_initializer(0.0, stddev) 再定义一个用于产生截断分布的函数
接下来定义inception v3 base,它可以生成inception v3的卷积部分
def inception_v3_base(inputs, final_endpoint='Mixed_7c', min_depth=16, depth_multiplier=1.0, scope=None): """Inception model from http://arxiv.org/abs/1512.00567. 总体名称对应结构如下 Old name | New name ======================================= conv0 | Conv2d_1a_3x3 conv1 | Conv2d_2a_3x3 conv2 | Conv2d_2b_3x3 pool1 | MaxPool_3a_3x3 conv3 | Conv2d_3b_1x1 conv4 | Conv2d_4a_3x3 pool2 | MaxPool_5a_3x3 mixed_35x35x256a | Mixed_5b mixed_35x35x288a | Mixed_5c mixed_35x35x288b | Mixed_5d mixed_17x17x768a | Mixed_6a mixed_17x17x768b | Mixed_6b mixed_17x17x768c | Mixed_6c mixed_17x17x768d | Mixed_6d mixed_17x17x768e | Mixed_6e mixed_8x8x1280a | Mixed_7a mixed_8x8x2048a | Mixed_7b mixed_8x8x2048b | Mixed_7c Args: inputs: a tensor of size [batch_size, height, width, channels]. final_endpoint: specifies the endpoint to construct the network up to. It can be one of ['Conv2d_1a_3x3', 'Conv2d_2a_3x3', 'Conv2d_2b_3x3', 'MaxPool_3a_3x3', 'Conv2d_3b_1x1', 'Conv2d_4a_3x3', 'MaxPool_5a_3x3', 'Mixed_5b', 'Mixed_5c', 'Mixed_5d', 'Mixed_6a', 'Mixed_6b', 'Mixed_6c', 'Mixed_6d', 'Mixed_6e', 'Mixed_7a', 'Mixed_7b', 'Mixed_7c']. min_depth: Minimum depth value (number of channels) for all convolution ops. Enforced when depth_multiplier < 1, and not an active constraint when depth_multiplier >= 1. depth_multiplier: Float multiplier for the depth (number of channels) for all convolution ops. The value must be greater than zero. Typical usage will be to set this value in (0, 1) to reduce the number of parameters or computation cost of the model. scope: Optional variable_scope. Returns: tensor_out: output tensor corresponding to the final_endpoint. end_points: a set of activations for external use, for example summaries or losses. Raises: ValueError: if final_endpoint is not set to one of the predefined values, or depth_multiplier <= 0 """ # end_points will collect relevant activations for external use, for example # summaries or losses. end_points = {} if depth_multiplier <= 0: raise ValueError('depth_multiplier is not greater than zero.') #用来计算深度的函数，与乘子结合 depth = lambda d: max(int(d * depth_multiplier), min_depth) with tf.variable_scope(scope, 'InceptionV3', [inputs]): with slim.arg_scope([slim.conv2d, slim.max_pool2d, slim.avg_pool2d], stride=1, padding='VALID'): # 299 x 299 x 3 end_point = 'Conv2d_1a_3x3' net = slim.conv2d(inputs, depth(32), [3, 3], stride=2, scope=end_point) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 149 x 149 x 32 end_point = 'Conv2d_2a_3x3' net = slim.conv2d(net, depth(32), [3, 3], scope=end_point) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 147 x 147 x 32 end_point = 'Conv2d_2b_3x3' net = slim.conv2d(net, depth(64), [3, 3], padding='SAME', scope=end_point) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 147 x 147 x 64 end_point = 'MaxPool_3a_3x3' net = slim.max_pool2d(net, [3, 3], stride=2, scope=end_point) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 73 x 73 x 64 end_point = 'Conv2d_3b_1x1' net = slim.conv2d(net, depth(80), [1, 1], scope=end_point) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 73 x 73 x 80. end_point = 'Conv2d_4a_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 # 71 x 71 x 192. end_point = 'MaxPool_5a_3x3' net = slim.max_pool2d(net, [3, 3], stride=2, scope=end_point) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 35 x 35 x 192. # 接下来将是三个连续的Inception模块组，模块组中各自分别有多个incpetion模块, # 这部分结构是Inception v3的精华 # Inception blocks 第一个模块组的名称为Mixed_5b # 先用slim设置所有inception Module的默认参数，所有卷积、最大池化、平均池化层的步长为1，padding为'SAME' with slim.arg_scope([slim.conv2d, slim.max_pool2d, slim.avg_pool2d], stride=1, padding='SAME'): # mixed: 35 x 35 x 256. end_point = 'Mixed_5b' with tf.variable_scope(end_point): #第一组模块有4个分支 #第一个分支为64通道的1x1卷积 with tf.variable_scope('Branch_0'): branch_0 = slim.conv2d(net, depth(64), [1, 1], scope='Conv2d_0a_1x1') #第二个分支为48通道的1x1卷积接一个64通道的5x5卷积 with tf.variable_scope('Branch_1'): branch_1 = slim.conv2d(net, depth(48), [1, 1], scope='Conv2d_0a_1x1') branch_1 = slim.conv2d(branch_1, depth(64), [5, 5], scope='Conv2d_0b_5x5') #第三个分支为64通道的1x1卷积接一个96通道的3x3的卷积 with tf.variable_scope('Branch_2'): branch_2 = slim.conv2d(net, depth(64), [1, 1], 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') #第四个分支为3x3平均池化接一个32通道的1x1卷积 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], scope='Conv2d_0b_1x1') #将4个分支的输出合并在一起，在输出通道维度上进行合并 net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2, branch_3]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points #由于设置了步长为1，padding为'same',所以尺寸不会减少，只是通道数量增加了 # 按照相同的方法设置第二个Inception Module，输出通道数为288 # mixed_1: 35 x 35 x 288. end_point = 'Mixed_5c' 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(48), [1, 1], scope='Conv2d_0b_1x1') branch_1 = slim.conv2d(branch_1, depth(64), [5, 5], scope='Conv_1_0c_5x5') with tf.variable_scope('Branch_2'): branch_2 = slim.conv2d(net, depth(64), [1, 1], 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], scope='Conv2d_0b_1x1') net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2, branch_3]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # mixed_2: 35 x 35 x 288. end_point = 'Mixed_5d' 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(48), [1, 1], scope='Conv2d_0a_1x1') branch_1 = slim.conv2d(branch_1, depth(64), [5, 5], scope='Conv2d_0b_5x5') with tf.variable_scope('Branch_2'): branch_2 = slim.conv2d(net, depth(64), [1, 1], 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], scope='Conv2d_0b_1x1') net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2, branch_3]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 第一个模块组的3个Module到这里结束 # 第二个模块组包含了5个Module,第2-5个结构相似 # mixed_3: 17 x 17 x 768. end_point = 'Mixed_6a' with tf.variable_scope(end_point): # 包含3分支 # 第一分支stride=2,尺寸压缩到17x17 with tf.variable_scope('Branch_0'): branch_0 = slim.conv2d(net, depth(384), [3, 3], stride=2, padding='VALID', scope='Conv2d_1a_1x1') #第二分支有三层，第一层是一个64通道的1x1卷积，第二层是96通道的3x3卷积，第三层是96通道3x3卷积，尺寸压缩 with tf.variable_scope('Branch_1'): branch_1 = slim.conv2d(net, depth(64), [1, 1], 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, padding='VALID', scope='Conv2d_1a_1x1') #第三个分支3x3最大池化层，尺寸同样压缩 with tf.variable_scope('Branch_2'): branch_2 = slim.max_pool2d(net, [3, 3], stride=2, padding='VALID', scope='MaxPool_1a_3x3') net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 所以最后的尺寸是17x17x(384+96+256)=17x17x768 # 随后的Module尺寸全部固定到17x17x768 # mixed4: 17 x 17 x 768. # 第二个模块组的第二个Module有4个分支 end_point = 'Mixed_6b' 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') # 第二个分支有3层卷积 # 第二层是一个128通道的1x7卷积，第三层是一个192通道的7x1卷积 # 这里用到了Factorization into small convolutions的思想，串联一个1x7和7x1的卷积相当于7x卷积 # 但是参数量大大减少了 ，只有2/7,同时多了一个激活函数增强了非线性特征变换，减轻了过拟合 with tf.variable_scope('Branch_1'): branch_1 = slim.conv2d(net, depth(128), [1, 1], scope='Conv2d_0a_1x1') branch_1 = slim.conv2d(branch_1, depth(128), [1, 7], scope='Conv2d_0b_1x7') branch_1 = slim.conv2d(branch_1, depth(192), [7, 1], scope='Conv2d_0c_7x1') with tf.variable_scope('Branch_2'): branch_2 = slim.conv2d(net, depth(128), [1, 1], scope='Conv2d_0a_1x1') branch_2 = slim.conv2d(branch_2, depth(128), [7, 1], scope='Conv2d_0b_7x1') branch_2 = slim.conv2d(branch_2, depth(128), [1, 7], scope='Conv2d_0c_1x7') branch_2 = slim.conv2d(branch_2, depth(128), [7, 1], scope='Conv2d_0d_7x1') branch_2 = slim.conv2d(branch_2, depth(192), [1, 7], scope='Conv2d_0e_1x7') 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(192), [1, 1], scope='Conv2d_0b_1x1') net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2, branch_3]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 最后该module的尺寸是17x17x(192+192+192+192)=17x17x768 # mixed_5: 17 x 17 x 768. end_point = 'Mixed_6c' 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'): #第二个模块组的第三个Module与第二个Module的不同就是第二个分支和第三个分支的前几个卷积层 # 的输出通道数不同，从128变成了160，最终通道数不变 # 这样做特征相当于被重新计算了一遍，对网络的丰富性提升很大 # 第一个Module包含3个分支 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') branch_0 = slim.conv2d(branch_0, depth(320), [3, 3], stride=2, padding='VALID', scope='Conv2d_1a_3x3') with tf.variable_scope('Branch_1'): branch_1 = slim.conv2d(net, depth(192), [1, 1], scope='Conv2d_0a_1x1') branch_1 = slim.conv2d(branch_1, depth(192), [1, 7], scope='Conv2d_0b_1x7') branch_1 = slim.conv2d(branch_1, depth(192), [7, 1], scope='Conv2d_0c_7x1') branch_1 = slim.conv2d(branch_1, depth(192), [3, 3], stride=2, padding='VALID', scope='Conv2d_1a_3x3') #这里的输出是8x8x768 with tf.variable_scope('Branch_2'): branch_2 = slim.max_pool2d(net, [3, 3], stride=2, padding='VALID', scope='MaxPool_1a_3x3') net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # 输出尺寸 8x8x(320+192+768)=8x8x1280 # mixed_9: 8 x 8 x 2048. end_point = 'Mixed_7b' with tf.variable_scope(end_point): with tf.variable_scope('Branch_0'): branch_0 = slim.conv2d(net, depth(320), [1, 1], scope='Conv2d_0a_1x1') with tf.variable_scope('Branch_1'): branch_1 = slim.conv2d(net, depth(384), [1, 1], scope='Conv2d_0a_1x1') branch_1 = tf.concat(axis=3, values=[ slim.conv2d(branch_1, depth(384), [1, 3], scope='Conv2d_0b_1x3'), slim.conv2d(branch_1, depth(384), [3, 1], scope='Conv2d_0b_3x1')]) # 第三个分支比较复杂 # 显示448通道的1x1卷积接一个384通道的3x3卷积，然后在分支内拆成两个分支，384通道1x3和3x1 # 最后合并的到8x8x768 with tf.variable_scope('Branch_2'): branch_2 = slim.conv2d(net, depth(448), [1, 1], scope='Conv2d_0a_1x1') branch_2 = slim.conv2d( branch_2, depth(384), [3, 3], scope='Conv2d_0b_3x3') branch_2 = tf.concat(axis=3, values=[ slim.conv2d(branch_2, depth(384), [1, 3], scope='Conv2d_0c_1x3'), slim.conv2d(branch_2, depth(384), [3, 1], scope='Conv2d_0d_3x1')]) 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(192), [1, 1], scope='Conv2d_0b_1x1') net = tf.concat(axis=3, values=[branch_0, branch_1, branch_2, branch_3]) end_points[end_point] = net if end_point == final_endpoint: return net, end_points # mixed_10: 8 x 8 x 2048. end_point = 'Mixed_7c' with tf.variable_scope(end_point): with tf.variable_scope('Branch_0'): branch_0 = slim.conv2d(net, depth(320), [1, 1], scope='Conv2d_0a_1x1') with tf.variable_scope('Branch_1'): branch_1 = slim.conv2d(net, depth(384), [1, 1], scope='Conv2d_0a_1x1') branch_1 = tf.concat(axis=3, values=[ slim.conv2d(branch_1, depth(384), [1, 3], scope='Conv2d_0b_1x3'), slim.conv2d(branch_1, depth(384), [3, 1], scope='Conv2d_0c_3x1')]) with tf.variable_scope('Branch_2'): branch_2 = slim.conv2d(net, depth(448), [1, 1], scope='Conv2d_0a_1x1') branch_2 = slim.conv2d( branch_2, depth(384), [3, 3], scope='Conv2d_0b_3x3') branch_2 = tf.concat(axis=3, values=[ slim.conv2d(branch_2, depth(384), [1, 3], scope='Conv2d_0c_1x3'), slim.conv2d(branch_2, depth(384), [3, 1], scope='Conv2d_0d_3x1')]) 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(192), [1, 1], scope='Conv2d_0b_1x1') net = tf.concat(axis=3, 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) 到这里Inception的核心部分完成，包含了3个inception模块组，每个模块组内包含了多个结构类似的Inceptionmodule。 图片的尺寸从299x299经过5个步长为2的卷结或池化后缩减到8x8,通道数从3一直到2048。 每个Inception模块组的目的都是奖空间结构简化，同时把空间信息转化为高阶抽象的特征信息。 这一过程使得每层输出tensor的size持续下降，降低了计算量。 可以发现InceptionModule的规律，一般情况下有4个分支，第1个分支一般是1x1卷积，第2个分支一般是1x1卷积后再接分解的1xn和nx1卷积 第3个分支和第2个分支类似,但是一般更深一些,第4个分支一般具有最大池化或者平均池化 因此，Inception Module是通过组合比较简单的特征抽象(分支1)，比较复杂的特征抽象(2,3),和一个简化的池化层(分支4)，一共4种不同程度的 特征抽象和变化来有选择的保留不同层次的高阶特征，最大程度丰富网络的表达能力 def inception_v3(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='InceptionV3'): """Inception model from http://arxiv.org/abs/1512.00567. "Rethinking the Inception Architecture for Computer Vision" Christian Szegedy, Vincent Vanhoucke, Sergey Ioffe, Jonathon Shlens, Zbigniew Wojna. With the default arguments this method constructs the exact model defined in the paper. However, one can experiment with variations of the inception_v3 network by changing arguments dropout_keep_prob, min_depth and depth_multiplier. The default image size used to train this network is 299x299. Args: inputs: a tensor of size [batch_size, height, width, channels]. num_classes: number of predicted classes. is_training: whether is training or not. dropout_keep_prob: the percentage of activation values that are retained. min_depth: Minimum depth value (number of channels) for all convolution ops. Enforced when depth_multiplier < 1, and not an active constraint when depth_multiplier >= 1. depth_multiplier: Float multiplier for the depth (number of channels) for all convolution ops. The value must be greater than zero. Typical usage will be to set this value in (0, 1) to reduce the number of parameters or computation cost of the model. prediction_fn: a function to get predictions out of logits. spatial_squeeze: if True, logits is of shape [B, C], if false logits is of shape [B, 1, 1, C], where B is batch_size and C is number of classes. reuse: whether or not the network and its variables should be reused. To be able to reuse 'scope' must be given. scope: Optional variable_scope. Returns: logits: the pre-softmax activations, a tensor of size [batch_size, num_classes] end_points: a dictionary from components of the network to the corresponding activation. Raises: ValueError: if 'depth_multiplier' is less than or equal to zero. """ if depth_multiplier <= 0: raise ValueError('depth_multiplier is not greater than zero.') depth = lambda d: max(int(d * depth_multiplier), min_depth) with tf.variable_scope(scope, 'InceptionV3', [inputs, num_classes], reuse=reuse) as scope: with slim.arg_scope([slim.batch_norm, slim.dropout], is_training=is_training): net, end_points = inception_v3_base( inputs, scope=scope, min_depth=min_depth, depth_multiplier=depth_multiplier) # Auxiliary Head logits # 先把卷积、最大池化、平均池化的默认步长设为1 with slim.arg_scope([slim.conv2d, slim.max_pool2d, slim.avg_pool2d], stride=1, padding='SAME'): aux_logits = end_points['Mixed_6e'] # 在6e之后接一个5x5的平均池化，步长为3，padding位VALID,这样尺寸从17x17x768变成5x5x768 with tf.variable_scope('AuxLogits'): aux_logits = slim.avg_pool2d( aux_logits, [5, 5], stride=3, padding='VALID', scope='AvgPool_1a_5x5') #接着连一个128通道的1x1卷积和一个768通道的的5x5卷积 aux_logits = slim.conv2d(aux_logits, depth(128), [1, 1], scope='Conv2d_1b_1x1') # Shape of feature map before the final layer. kernel_size = _reduced_kernel_size_for_small_input( aux_logits, [5, 5]) aux_logits = slim.conv2d( aux_logits, depth(768), kernel_size, weights_initializer=trunc_normal(0.01), padding='VALID', scope='Conv2d_2a_{}x{}'.format(*kernel_size)) # 最后接一个输出通道为num_classes的1x1卷积，不设置激活函数和规范化函数 # 输出变成了1x1x1000 aux_logits = slim.conv2d( aux_logits, num_classes, [1, 1], activation_fn=None, normalizer_fn=None, weights_initializer=trunc_normal(0.001), scope='Conv2d_2b_1x1') # 消除tensor中前两个为1的维度 if spatial_squeeze: aux_logits = tf.squeeze(aux_logits, [1, 2], name='SpatialSqueeze') end_points['AuxLogits'] = aux_logits # 之后就是正常的分类预测 # Final pooling and prediction with tf.variable_scope('Logits'): kernel_size = _reduced_kernel_size_for_small_input(net, [8, 8]) net = slim.avg_pool2d(net, kernel_size, padding='VALID', scope='AvgPool_1a_{}x{}'.format(*kernel_size)) # 1 x 1 x 2048 net = slim.dropout(net, keep_prob=dropout_keep_prob, scope='Dropout_1b') end_points['PreLogits'] = net # 2048 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') # 1000 end_points['Logits'] = logits end_points['Predictions'] = prediction_fn(logits, scope='Predictions') return logits, end_points