Example #1
0
    def build_model(self, img_input: TensorType) -> TensorType:
        """Build graph using img_input as input.

        Args:
            img_input: 4D Image input tensor of shape (batch, height, width, channels)

        Returns:
            `Tensor` holding output probabilities per class, shape (batch, num_classes)
        """

        x = layers.conv(img_input,
                        filters_out=64,
                        kernel_size=7,
                        stride=2,
                        add_bias=False,
                        name='conv1_conv')
        x = layers.norm(x, axis=-1, epsilon=1.001e-5, name='conv1_bn')
        x = layers.relu(x, name='conv1_relu')
        x = layers.zero_padding(x, padding=((1, 1), (1, 1)), name='pool1_pad')
        x = layers.max_pool(x, kernel_size=3, name='pool1')

        x = self.conv_block(x, 3, [64, 64, 256], stage=2, block='1', strides=1)
        x = self.identity_block(x, 3, [64, 64, 256], stage=2, block='2')
        x = self.identity_block(x, 3, [64, 64, 256], stage=2, block='3')

        x = self.conv_block(x, 3, [128, 128, 512], stage=3, block='1')
        x = self.identity_block(x, 3, [128, 128, 512], stage=3, block='2')
        x = self.identity_block(x, 3, [128, 128, 512], stage=3, block='3')
        x = self.identity_block(x, 3, [128, 128, 512], stage=3, block='4')

        x = self.conv_block(x, 3, [256, 256, 1024], stage=4, block='1')
        x = self.identity_block(x, 3, [256, 256, 1024], stage=4, block='2')
        x = self.identity_block(x, 3, [256, 256, 1024], stage=4, block='3')
        x = self.identity_block(x, 3, [256, 256, 1024], stage=4, block='4')
        x = self.identity_block(x, 3, [256, 256, 1024], stage=4, block='5')
        x = self.identity_block(x, 3, [256, 256, 1024], stage=4, block='6')

        x = self.conv_block(x, 3, [512, 512, 2048], stage=5, block='1')
        x = self.identity_block(x, 3, [512, 512, 2048], stage=5, block='2')
        x = self.identity_block(x, 3, [512, 512, 2048], stage=5, block='3')

        x = layers.avg_pool(x, kernel_size=7, strides=1, name='avg_pool')
        x = layers.squeeze(x, axis=[1, 2], name='squeeze')
        x = layers.fully_connected(x, self.num_classes, name='probs')
        x = layers.softmax(x, name='output-prob')
        return x
Example #2
0
    def inception_block(
            x: TensorType,
            specs: Tuple,
            channel_axis: int,
            name: str,
            weight_suffix: Optional[str] = "weights",
            conv_suffix: Optional[str] = "",
            norm_suffix: Optional[str] = "/BatchNorm") -> TensorType:
        """Inception block.

        Args:
            x: input_tensor
            specs: Number of filters per branch.
            channel_axis: channel dimension
            name: Prefix for ths block.
            weight_suffix: Name of learn-able parameters in conv.
            conv_suffix: Suffix for conv layer.
            norm_suffix: Suffix for batch norm.

        Returns: Concatenated output of inception block.

        """
        (br0, br1, br2, br3) = specs  # ((64,), (96,128), (16,32), (32,))

        branch_0 = conv_norm_relu(x,
                                  br0[0],
                                  1,
                                  1,
                                  name=name + "/Branch_0/Conv2d_0a_1x1",
                                  weight_suffix=weight_suffix,
                                  conv_suffix=conv_suffix,
                                  norm_suffix=norm_suffix)

        branch_1 = conv_norm_relu(x,
                                  br1[0],
                                  1,
                                  1,
                                  name=name + "/Branch_1/Conv2d_0a_1x1",
                                  weight_suffix=weight_suffix,
                                  conv_suffix=conv_suffix,
                                  norm_suffix=norm_suffix)
        branch_1 = conv_norm_relu(branch_1,
                                  br1[1],
                                  3,
                                  3,
                                  name=name + "/Branch_1/Conv2d_0b_3x3",
                                  weight_suffix=weight_suffix,
                                  conv_suffix=conv_suffix,
                                  norm_suffix=norm_suffix)

        branch_2 = conv_norm_relu(x,
                                  br2[0],
                                  1,
                                  1,
                                  name=name + "/Branch_2/Conv2d_0a_1x1",
                                  weight_suffix=weight_suffix,
                                  conv_suffix=conv_suffix,
                                  norm_suffix=norm_suffix)
        if name == "InceptionV1/Mixed_5b":
            branch_2b_name = name + "/Branch_2/Conv2d_0a_3x3"
        else:
            branch_2b_name = name + "/Branch_2/Conv2d_0b_3x3"
        branch_2 = conv_norm_relu(branch_2,
                                  br2[1],
                                  3,
                                  3,
                                  name=branch_2b_name,
                                  weight_suffix=weight_suffix,
                                  conv_suffix=conv_suffix,
                                  norm_suffix=norm_suffix)

        branch_3 = max_pool(x,
                            3,
                            strides=1,
                            padding='same',
                            name=name + "/Branch_3/Conv2d_0a_max")
        branch_3 = conv_norm_relu(branch_3,
                                  br3[0],
                                  1,
                                  1,
                                  name=name + "/Branch_3/Conv2d_0b_1x1",
                                  weight_suffix=weight_suffix,
                                  conv_suffix=conv_suffix,
                                  norm_suffix=norm_suffix)

        x = concat([branch_0, branch_1, branch_2, branch_3],
                   axis=channel_axis,
                   name=name + "_Concatenated")
        return x
Example #3
0
    def build_model(self, img_input: TensorType) -> TensorType:
        """Build graph using img_input as input.

        Args:
            img_input: 4D Image input tensor of shape (batch, height, width,
            channels)

        Returns:
            `Tensor` holding output probabilities per class, shape (batch,
            num_classes)
        """
        channel_axis = -1

        x = conv_norm_relu(img_input,
                           64,
                           7,
                           strides=2,
                           padding='SAME',
                           name='InceptionV1/Conv2d_1a_7x7',
                           norm_suffix="/BatchNorm",
                           weight_suffix="weights",
                           conv_suffix="")

        x = max_pool(x, 3, strides=2, padding='same', name='MaxPool_2a_3x3')
        x = conv_norm_relu(x,
                           64,
                           1,
                           padding='same',
                           name='InceptionV1/Conv2d_2b_1x1',
                           weight_suffix="weights",
                           conv_suffix="",
                           norm_suffix="/BatchNorm")
        x = conv_norm_relu(x,
                           192,
                           3,
                           padding='same',
                           name='InceptionV1/Conv2d_2c_3x3',
                           weight_suffix="weights",
                           conv_suffix="",
                           norm_suffix="/BatchNorm")
        x = max_pool(x, 3, strides=2, padding='same', name='MaxPool_3a_3x3')

        # Now the '3' level inception units
        x = self.inception_block(x, ((64, ), (96, 128), (16, 32), (32, )),
                                 channel_axis, 'InceptionV1/Mixed_3b')
        x = self.inception_block(x, ((128, ), (128, 192), (32, 96), (64, )),
                                 channel_axis, 'InceptionV1/Mixed_3c')

        x = max_pool(x, 3, strides=2, padding='same', name='MaxPool_4a_3x3')

        # Now the '4' level inception units
        x = self.inception_block(x, ((192, ), (96, 208), (16, 48), (64, )),
                                 channel_axis, 'InceptionV1/Mixed_4b')
        x = self.inception_block(x, ((160, ), (112, 224), (24, 64), (64, )),
                                 channel_axis, 'InceptionV1/Mixed_4c')
        x = self.inception_block(x, ((128, ), (128, 256), (24, 64), (64, )),
                                 channel_axis, 'InceptionV1/Mixed_4d')
        x = self.inception_block(x, ((112, ), (144, 288), (32, 64), (64, )),
                                 channel_axis, 'InceptionV1/Mixed_4e')
        x = self.inception_block(x, ((256, ), (160, 320), (32, 128), (128, )),
                                 channel_axis, 'InceptionV1/Mixed_4f')

        x = max_pool(x, 2, strides=2, padding='same', name='MaxPool_5a_2x2')

        # Now the '5' level inception units
        x = self.inception_block(x, ((256, ), (160, 320), (32, 128), (128, )),
                                 channel_axis, 'InceptionV1/Mixed_5b')
        x = self.inception_block(x, ((384, ), (192, 384), (48, 128), (128, )),
                                 channel_axis, 'InceptionV1/Mixed_5c')

        # Classification block
        x = avg_pool(x,
                     kernel_size=7,
                     strides=1,
                     name='avg_pool',
                     padding='valid')
        x = conv(x,
                 filters_out=self.num_classes + 1,
                 kernel_size=1,
                 padding='valid',
                 add_bias=True,
                 name='InceptionV1/Logits/Conv2d_0c_1x1',
                 weight_suffix="weights",
                 bias_suffix="biases")
        x = squeeze(x, axis=[1, 2], name='squeeze')
        x = softmax(x, name='output-prob')

        return x
Example #4
0
    def build_model(self, img_input: TensorType) -> TensorType:
        """Build graph using img_input as input.

        Args:
            img_input: 4D Image input tensor of shape (batch, height, width, channels)

        Returns:
            `Tensor` holding output probabilities per class, shape (batch, num_classes)
        """

        x = conv_norm_relu(img_input, 32, 3, strides=2, padding='VALID')
        x = conv_norm_relu(x, 32, 3, padding='VALID')
        x = conv_norm_relu(
            x,
            64,
            3,
        )
        x = max_pool(x, 3, strides=2)

        x = conv_norm_relu(x, 80, 1, padding='VALID')
        x = conv_norm_relu(x, 192, 3, padding='VALID')
        x = max_pool(x, 3, strides=2)

        # mixed 0: 35 x 35 x 256
        branch1x1 = conv_norm_relu(x, 64, 1)

        branch5x5 = conv_norm_relu(x, 48, 1)
        branch5x5 = conv_norm_relu(branch5x5, 64, 5)

        branch3x3dbl = conv_norm_relu(x, 64, 1)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)

        branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
        branch_pool = conv_norm_relu(branch_pool, 32, 1)
        x = concat([branch1x1, branch5x5, branch3x3dbl, branch_pool],
                   axis=-1,
                   name='mixed0')

        # mixed 1: 35 x 35 x 288
        branch1x1 = conv_norm_relu(x, 64, 1)

        branch5x5 = conv_norm_relu(x, 48, 1)
        branch5x5 = conv_norm_relu(branch5x5, 64, 5)

        branch3x3dbl = conv_norm_relu(x, 64, 1)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)

        branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
        branch_pool = conv_norm_relu(branch_pool, 64, 1)
        x = concat([branch1x1, branch5x5, branch3x3dbl, branch_pool],
                   axis=-1,
                   name='mixed1')

        # mixed 2: 35 x 35 x 288
        branch1x1 = conv_norm_relu(x, 64, 1)

        branch5x5 = conv_norm_relu(x, 48, 1)
        branch5x5 = conv_norm_relu(branch5x5, 64, 5)

        branch3x3dbl = conv_norm_relu(x, 64, 1)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)

        branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
        branch_pool = conv_norm_relu(branch_pool, 64, 1)
        x = concat([branch1x1, branch5x5, branch3x3dbl, branch_pool],
                   axis=-1,
                   name='mixed2')

        # mixed 3: 17 x 17 x 768
        branch3x3 = conv_norm_relu(x, 384, 3, strides=2, padding='VALID')

        branch3x3dbl = conv_norm_relu(x, 64, 1)
        branch3x3dbl = conv_norm_relu(branch3x3dbl, 96, 3)
        branch3x3dbl = conv_norm_relu(branch3x3dbl,
                                      96,
                                      3,
                                      strides=2,
                                      padding='VALID')

        branch_pool = max_pool(x, 3, 2)
        x = concat([branch3x3, branch3x3dbl, branch_pool],
                   axis=-1,
                   name='mixed3')

        # mixed 4: 17 x 17 x 768
        branch1x1 = conv_norm_relu(x, 192, 1)

        branch7x7 = conv_norm_relu(x, 128, 1)
        branch7x7 = conv_norm_relu(branch7x7, 128, 1, 7)
        branch7x7 = conv_norm_relu(branch7x7, 192, 7, 1)

        branch7x7dbl = conv_norm_relu(x, 128, 1, 1)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 128, 7, 1)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 128, 1, 7)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 128, 7, 1)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 192, 1, 7)

        branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
        branch_pool = conv_norm_relu(branch_pool, 192, 1, 1)
        x = concat([branch1x1, branch7x7, branch7x7dbl, branch_pool],
                   axis=-1,
                   name='mixed4')

        # mixed 5, 6: 17 x 17 x 768
        for i in range(2):
            branch1x1 = conv_norm_relu(x, 192, 1, 1)

            branch7x7 = conv_norm_relu(x, 160, 1, 1)
            branch7x7 = conv_norm_relu(branch7x7, 160, 1, 7)
            branch7x7 = conv_norm_relu(branch7x7, 192, 7, 1)

            branch7x7dbl = conv_norm_relu(x, 160, 1, 1)
            branch7x7dbl = conv_norm_relu(branch7x7dbl, 160, 7, 1)
            branch7x7dbl = conv_norm_relu(branch7x7dbl, 160, 1, 7)
            branch7x7dbl = conv_norm_relu(branch7x7dbl, 160, 7, 1)
            branch7x7dbl = conv_norm_relu(branch7x7dbl, 192, 1, 7)

            branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
            branch_pool = conv_norm_relu(branch_pool, 192, 1, 1)
            x = concat([branch1x1, branch7x7, branch7x7dbl, branch_pool],
                       axis=-1,
                       name='mixed' + str(5 + i))

        # mixed 7: 17 x 17 x 768
        branch1x1 = conv_norm_relu(x, 192, 1, 1)

        branch7x7 = conv_norm_relu(x, 192, 1, 1)
        branch7x7 = conv_norm_relu(branch7x7, 192, 1, 7)
        branch7x7 = conv_norm_relu(branch7x7, 192, 7, 1)

        branch7x7dbl = conv_norm_relu(x, 192, 1, 1)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 192, 7, 1)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 192, 1, 7)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 192, 7, 1)
        branch7x7dbl = conv_norm_relu(branch7x7dbl, 192, 1, 7)

        branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
        branch_pool = conv_norm_relu(branch_pool, 192, 1, 1)
        x = concat([branch1x1, branch7x7, branch7x7dbl, branch_pool],
                   axis=-1,
                   name='mixed7')

        # mixed 8: 8 x 8 x 1280
        branch3x3 = conv_norm_relu(x, 192, 1)
        branch3x3 = conv_norm_relu(branch3x3,
                                   320,
                                   3,
                                   strides=2,
                                   padding='VALID')

        branch7x7x3 = conv_norm_relu(x, 192, 1, 1)
        branch7x7x3 = conv_norm_relu(branch7x7x3, 192, 1, 7)
        branch7x7x3 = conv_norm_relu(branch7x7x3, 192, 7, 1)
        branch7x7x3 = conv_norm_relu(branch7x7x3,
                                     192,
                                     3,
                                     3,
                                     strides=2,
                                     padding='VALID')

        branch_pool = max_pool(x, 3, strides=2)
        x = concat([branch3x3, branch7x7x3, branch_pool],
                   axis=-1,
                   name='mixed8')

        # mixed 9: 8 x 8 x 2048
        for i in range(2):
            branch1x1 = conv_norm_relu(x, 320, 1, 1)

            branch3x3 = conv_norm_relu(x, 384, 1, 1)
            branch3x3_1 = conv_norm_relu(branch3x3, 384, 1, 3)
            branch3x3_2 = conv_norm_relu(branch3x3, 384, 3, 1)
            branch3x3 = concat([branch3x3_1, branch3x3_2],
                               axis=-1,
                               name='mixed9_' + str(i))

            branch3x3dbl = conv_norm_relu(x, 448, 1, 1)
            branch3x3dbl = conv_norm_relu(branch3x3dbl, 384, 3, 3)
            branch3x3dbl_1 = conv_norm_relu(branch3x3dbl, 384, 1, 3)
            branch3x3dbl_2 = conv_norm_relu(branch3x3dbl, 384, 3, 1)
            branch3x3dbl = concat([branch3x3dbl_1, branch3x3dbl_2], axis=-1)

            branch_pool = avg_pool(x, 3, strides=1, padding='SAME')
            branch_pool = conv_norm_relu(branch_pool, 192, 1, 1)
            x = concat([branch1x1, branch3x3, branch3x3dbl, branch_pool],
                       axis=-1,
                       name='mixed' + str(9 + i))

        # Classification block
        x = avg_pool(x, kernel_size=8, strides=1, name='avg_pool')
        x = squeeze(x, axis=[1, 2], name='squeeze')
        x = fully_connected(x, self.num_classes, name='predictions')
        x = softmax(x, name='output-prob')

        return x
Example #5
0
    def build_model(self, img_input: TensorType) -> TensorType:
        """Build graph using img_input as input.

        Args:
            img_input: 4D Image input tensor of shape (batch, height, width, channels)

        Returns:
            `Tensor` holding output probabilities per class, shape (batch, num_classes)
        """

        x = layers.conv(img_input, filters_out=32, kernel_size=3, stride=2, add_bias=False, name='block1_conv1')
        x = layers.norm(x, name='block1_conv1_bn')
        x = layers.relu(x, name='block1_conv1_act')
        x = layers.conv(x, filters_out=64, kernel_size=3, add_bias=False, name='block1_conv2')
        x = layers.norm(x, name='block1_conv2_bn')
        x = layers.relu(x, name='block1_conv2_act')

        residual = layers.conv(x, filters_out=128, kernel_size=1, stride=2, padding='same', add_bias=False)
        residual = layers.norm(residual, name="batch_normalization")

        x = layers.separable_conv(x, filters_out=128, kernel_size=3, padding='same', add_bias=False,
                                  name='block2_sepconv1')
        x = layers.norm(x, name='block2_sepconv1_bn')
        x = layers.relu(x, name='block2_sepconv2_act')
        x = layers.separable_conv(x, filters_out=128, kernel_size=3, padding='same', add_bias=False,
                                  name='block2_sepconv2')
        x = layers.norm(x, name='block2_sepconv2_bn')

        x = layers.max_pool(x, 3, strides=2, padding='same', name='block2_pool')
        x += residual

        residual = layers.conv(x, filters_out=256, kernel_size=1, stride=2, padding='same', add_bias=False)
        residual = layers.norm(residual, name="batch_normalization")

        x = layers.relu(x, name='block3_sepconv1_act')
        x = layers.separable_conv(x, filters_out=256, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block3_sepconv1')
        x = layers.norm(x, name='block3_sepconv1_bn')
        x = layers.relu(x, name='block3_sepconv2_act')
        x = layers.separable_conv(x, filters_out=256, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block3_sepconv2')
        x = layers.norm(x, name='block3_sepconv2_bn')

        x = layers.max_pool(x, 3, strides=2,
                            padding='same',
                            name='block3_pool')
        x += residual

        residual = layers.conv(x, filters_out=728, kernel_size=1,
                               stride=2,
                               padding='same',
                               add_bias=False)
        residual = layers.norm(residual, name="batch_normalization")

        x = layers.relu(x, name='block4_sepconv1_act')
        x = layers.separable_conv(x, filters_out=728, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block4_sepconv1')
        x = layers.norm(x, name='block4_sepconv1_bn')
        x = layers.relu(x, name='block4_sepconv2_act')
        x = layers.separable_conv(x, filters_out=728, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block4_sepconv2')
        x = layers.norm(x, name='block4_sepconv2_bn')

        x = layers.max_pool(x, 3, strides=2,
                            padding='same',
                            name='block4_pool')
        x += residual

        for i in range(8):
            residual = x
            prefix = 'block' + str(i + 5)

            x = layers.relu(x, name=prefix + '_sepconv1_act')
            x = layers.separable_conv(x, filters_out=728, kernel_size=3,
                                      padding='same',
                                      add_bias=False,
                                      name=prefix + '_sepconv1')
            x = layers.norm(x, name=prefix + '_sepconv1_bn')
            x = layers.relu(x, name=prefix + '_sepconv2_act')
            x = layers.separable_conv(x, filters_out=728, kernel_size=3,
                                      padding='same',
                                      add_bias=False,
                                      name=prefix + '_sepconv2')
            x = layers.norm(x, name=prefix + '_sepconv2_bn')
            x = layers.relu(x, name=prefix + '_sepconv3_act')
            x = layers.separable_conv(x, filters_out=728, kernel_size=3,
                                      padding='same',
                                      add_bias=False,
                                      name=prefix + '_sepconv3')
            x = layers.norm(x, name=prefix + '_sepconv3_bn')

            x += residual

        residual = layers.conv(x, filters_out=1024, kernel_size=1, stride=2,
                               padding='same', add_bias=False)
        residual = layers.norm(residual, name="batch_normalization")

        x = layers.relu(x, name='block13_sepconv1_act')
        x = layers.separable_conv(x, filters_out=728, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block13_sepconv1')
        x = layers.norm(x, name='block13_sepconv1_bn')
        x = layers.relu(x, name='block13_sepconv2_act')
        x = layers.separable_conv(x, filters_out=1024, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block13_sepconv2')
        x = layers.norm(x, name='block13_sepconv2_bn')

        x = layers.max_pool(x, 3,
                            strides=2,
                            padding='same',
                            name='block13_pool')
        x += residual

        x = layers.separable_conv(x, filters_out=1536, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block14_sepconv1')
        x = layers.norm(x, name='block14_sepconv1_bn')
        x = layers.relu(x, name='block14_sepconv1_act')

        x = layers.separable_conv(x, filters_out=2048, kernel_size=3,
                                  padding='same',
                                  add_bias=False,
                                  name='block14_sepconv2')
        x = layers.norm(x, name='block14_sepconv2_bn')
        x = layers.relu(x, name='block14_sepconv2_act')

        # Classification block
        x = layers.avg_pool(x, kernel_size=10, strides=1, name='avg_pool')
        x = layers.squeeze(x, axis=[1, 2], name='squeeze')
        x = layers.fully_connected(x, self.num_classes, name='predictions')
        x = layers.softmax(x, name='output-prob')

        return x
    def reduction_a_cell(ip, p, filters, block_id=None):
        """Adds a Reduction cell for NASNet-A (Fig. 4 in the paper).

         Args:
             ip: Input tensor `x`
             p: Input tensor `p`
             filters: Number of output filters
             block_id: String block_id

         Returns:
             A tf tensor
         """
        channel_dim = -1

        with tf.name_scope('reduction_A_block_%s' % block_id):
            p = NASNetMobile.adjust_block(p, ip, filters, block_id)

            h = layers.relu(ip)
            h = layers.conv(h,
                            filters_out=filters,
                            kernel_size=(1, 1),
                            stride=1,
                            padding='same',
                            name='reduction_conv_1_%s' % block_id,
                            add_bias=False)
            h = layers.norm(h,
                            axis=channel_dim,
                            momentum=0.9997,
                            epsilon=1e-3,
                            name='reduction_bn_1_%s' % block_id)

            h3 = layers.zero_padding(h,
                                     padding=NASNetMobile.correct_pad(
                                         h, (3, 3)),
                                     name='reduction_pad_1_%s' % block_id)

            with tf.name_scope('block_1'):
                x1_1 = NASNetMobile.separable_conv_block(
                    h,
                    filters=filters,
                    kernel_size=5,
                    strides=2,
                    block_id='reduction_left1_%s' % block_id)
                x1_2 = NASNetMobile.separable_conv_block(
                    p,
                    filters=filters,
                    kernel_size=7,
                    strides=2,
                    block_id='reduction_right1_%s' % block_id)
                x1 = x1_1 + x1_2

            with tf.name_scope('block_2'):
                x2_1 = layers.max_pool(h3,
                                       3,
                                       strides=2,
                                       padding='valid',
                                       name='reduction_left2_%s' % block_id)
                x2_2 = NASNetMobile.separable_conv_block(
                    p,
                    filters=filters,
                    kernel_size=7,
                    strides=2,
                    block_id='reduction_right2_%s' % block_id)
                x2 = x2_1 + x2_2

            with tf.name_scope('block_3'):
                x3_1 = layers.avg_pool(h3,
                                       3,
                                       strides=2,
                                       padding='valid',
                                       name='reduction_left3_%s' % block_id)
                x3_2 = NASNetMobile.separable_conv_block(
                    p,
                    filters,
                    5,
                    strides=2,
                    block_id='reduction_right3_%s' % block_id)
                x3 = x3_1 + x3_2

            with tf.name_scope('block_4'):
                x4 = layers.avg_pool(x1,
                                     3,
                                     strides=1,
                                     padding='same',
                                     name='reduction_left4_%s' % block_id)
                x4 += x2

            with tf.name_scope('block_5'):
                x5_1 = NASNetMobile.separable_conv_block(
                    x1, filters, 3, block_id='reduction_left4_%s' % block_id)
                x5_2 = layers.max_pool(h3,
                                       3,
                                       strides=2,
                                       padding='valid',
                                       name='reduction_right5_%s' % block_id)
                x5 = x5_1 + x5_2

            x = layers.concat([x2, x3, x4, x5],
                              axis=channel_dim,
                              name='reduction_concat_%s' % block_id)
            return x, ip