The need for transposed convolutions generally arise from the desire to use
a transformation going in the opposite direction of a normal convolution,
i.e., from something that has the shape of the output of some convolution
to something that has the shape of its input while maintaining a
connectivity pattern that is compatible with said convolution.
Args
filters
int, the dimension of the output space (the number of filters
in the transposed convolution).
kernel_size
int or tuple/list of 1 integer, specifying the size of the
transposed convolution window.
strides
int or tuple/list of 1 integer, specifying the stride length
of the transposed convolution. strides > 1 is incompatible with
dilation_rate > 1.
padding
string, either "valid" or "same" (case-insensitive).
"valid" means no padding. "same" results in padding evenly to
the left/right or up/down of the input. When padding="same" and
strides=1, the output has the same size as the input.
output_padding
An integer or tuple/list of 2 integers,
specifying the amount of padding along the height and width
of the output tensor.
Can be a single integer to specify the same value for all
spatial dimensions.
The amount of output padding along a given dimension must be
lower than the stride along that same dimension.
If set to None (default), the output shape is inferred.
data_format
string, either "channels_last" or "channels_first".
The ordering of the dimensions in the inputs. "channels_last"
corresponds to inputs with shape
(batch_size, height, width, channels)
while "channels_first" corresponds to inputs with shape
(batch_size, channels, height, width). It defaults to the
image_data_format value found in your Keras config file at
~/.keras/keras.json. If you never set it, then it will be
"channels_last".
dilation_rate: An integer or tuple/list of 2 integers,
specifying the dilation rate for
all spatial dimensions for dilated convolution.
Specifying different dilation rates
for different dimensions is not supported.
Currently, specifying any dilation_rate value != 1 is
incompatible with specifying any stride value != 1.
activation
Activation function. If None, no activation is applied.
use_bias
bool, if True, bias will be added to the output.
kernel_initializer
Initializer for the convolution kernel. If None,
the default initializer ("glorot_uniform") will be used.
bias_initializer
Initializer for the bias vector. If None, the
default initializer ("zeros") will be used.
kernel_regularizer
Optional regularizer for the convolution kernel.
bias_regularizer
Optional regularizer for the bias vector.
activity_regularizer
Optional regularizer function for the output.
kernel_constraint
Optional projection function to be applied to the
kernel after being updated by an Optimizer (e.g. used to implement
norm constraints or value constraints for layer weights). The
function must take as input the unprojected variable and must return
the projected variable (which must have the same shape). Constraints
are not safe to use when doing asynchronous distributed training.
bias_constraint
Optional projection function to be applied to the
bias after being updated by an Optimizer.
Input shape:
If data_format="channels_last":
A 4D tensor with shape: (batch_size, height, width, channels)
If data_format="channels_first":
A 4D tensor with shape: (batch_size, channels, height, width)
Output shape:
If data_format="channels_last":
A 4D tensor with shape: (batch_size, new_height, new_width, filters)
If data_format="channels_first":
A 4D tensor with shape: (batch_size, filters, new_height, new_width)
Returns
A 4D tensor representing
activation(conv2d_transpose(inputs, kernel) + bias).