def yolo_head(graph, feats, anchors, num_classes):
with graph.as_default():
num_anchors = len(anchors)
anchors_tensor = K.reshape(K.variable(anchors),
[1, 1, 1, num_anchors, 2])
conv_dims = K.shape(feats)[1:3]
conv_height_index = K.arange(0, stop=conv_dims[0])
conv_width_index = K.arange(0, stop=conv_dims[1])
conv_height_index = K.tile(conv_height_index, [conv_dims[1]])
conv_width_index = K.tile(K.expand_dims(conv_width_index, 0),
[conv_dims[0], 1])
conv_width_index = K.flatten(K.transpose(conv_width_index))
conv_index = K.transpose(K.stack([conv_height_index,
conv_width_index]))
conv_index = K.reshape(conv_index,
[1, conv_dims[0], conv_dims[1], 1, 2])
conv_index = K.cast(conv_index, K.dtype(feats))
feats = K.reshape(
feats,
[-1, conv_dims[0], conv_dims[1], num_anchors, num_classes + 5])
conv_dims = K.cast(K.reshape(conv_dims, [1, 1, 1, 1, 2]),
K.dtype(feats))
box_xy = K.sigmoid(feats[..., :2])
box_wh = K.exp(feats[..., 2:4])
box_confidence = K.sigmoid(feats[..., 4:5])
box_class_probs = K.softmax(feats[..., 5:])
box_xy = (box_xy + conv_index) / conv_dims
box_wh = box_wh * anchors_tensor / conv_dims
return box_xy, box_wh, box_confidence, box_class_probs
def yolo_head(feats, anchors, num_classes, input_shape, calc_loss=False):
"""Convert final layer features to bounding box parameters."""
num_anchors = len(anchors)
# Reshape to batch, height, width, num_anchors, box_params.
anchors_tensor = K.reshape(K.constant(anchors), [1, 1, 1, num_anchors, 2])
grid_shape = K.shape(feats)[1:3] # height, width
grid_y = K.tile(K.reshape(K.arange(0, stop=grid_shape[0]), [-1, 1, 1, 1]),
[1, grid_shape[1], 1, 1])
grid_x = K.tile(K.reshape(K.arange(0, stop=grid_shape[1]), [1, -1, 1, 1]),
[grid_shape[0], 1, 1, 1])
grid = K.concatenate([grid_x, grid_y])
grid = K.cast(grid, K.dtype(feats))
feats = K.reshape(
feats,
[-1, grid_shape[0], grid_shape[1], num_anchors, num_classes + 5])
# Adjust preditions to each spatial grid point and anchor size.
box_xy = (K.sigmoid(feats[..., :2]) + grid) / K.cast(
grid_shape[::-1], K.dtype(feats))
box_wh = K.exp(feats[..., 2:4]) * anchors_tensor / K.cast(
input_shape[::-1], K.dtype(feats))
box_confidence = K.sigmoid(feats[..., 4:5])
box_class_probs = K.sigmoid(feats[..., 5:])
if calc_loss == True:
return grid, feats, box_xy, box_wh
return box_xy, box_wh, box_confidence, box_class_probs
def get_initial_state(self, inputs):
if type(self.model.input) is not list:
return []
try:
batch_size = K.int_shape(inputs)[0]
except:
batch_size = None
state_shapes = list(map(K.int_shape, self.model.input[1:]))
states = []
if self.readout:
state_shapes.pop()
# default value for initial_readout is handled in call()
for shape in state_shapes:
if None in shape[1:]:
raise Exception(
'Only the batch dimension of a state can be left unspecified. Got state with shape '
+ str(shape))
if shape[0] is None:
ndim = K.ndim(inputs)
z = K.zeros_like(inputs)
slices = [slice(None)] + [0] * (ndim - 1)
z = z[slices] # (batch_size,)
state_ndim = len(shape)
z = K.reshape(z, (-1, ) + (1, ) * (state_ndim - 1))
z = K.tile(z, (1, ) + tuple(shape[1:]))
states.append(z)
else:
states.append(K.zeros(shape))
state_initializer = self.state_initializer
if state_initializer:
# some initializers don't accept symbolic shapes
for i in range(len(state_shapes)):
if state_shapes[i][0] is None:
if hasattr(self, 'batch_size'):
state_shapes[i] = (
self.batch_size, ) + state_shapes[i][1:]
if None in state_shapes[i]:
state_shapes[i] = K.shape(states[i])
num_state_init = len(state_initializer)
num_state = self.num_states
assert num_state_init == num_state, 'RNN has ' + str(
num_state) + ' states, but was provided ' + str(
num_state_init) + ' state initializers.'
for i in range(len(states)):
init = state_initializer[i]
shape = state_shapes[i]
try:
if not isinstance(init, initializers.Zeros):
states[i] = init(shape)
except:
raise Exception(
'Seems the initializer ' + init.__class__.__name__ +
' does not support symbolic shapes(' + str(shape) +
'). Try providing the full input shape (include batch dimension) for you RecurrentModel.'
)
return states
def test_tile(self):
shape = (3, 4)
arr = np.arange(np.prod(shape)).reshape(shape)
arr_th = KTH.variable(arr)
arr_tf = KTF.variable(arr)
n = (2, 1)
th_rep = KTH.eval(KTH.tile(arr_th, n))
tf_rep = KTF.eval(KTF.tile(arr_tf, n))
assert_allclose(tf_rep, th_rep, atol=1e-05)
def test_tile(self):
shape = (3, 4)
arr = np.arange(np.prod(shape)).reshape(shape)
arr_th = KTH.variable(arr)
arr_tf = KTF.variable(arr)
n = (2, 1)
th_rep = KTH.eval(KTH.tile(arr_th, n))
tf_rep = KTF.eval(KTF.tile(arr_tf, n))
assert_allclose(tf_rep, th_rep, atol=1e-05)
def test_tile(self):
shape = (3, 4)
arr = np.arange(np.prod(shape)).reshape(shape)
arr_th = KTH.variable(arr)
arr_tf = KTF.variable(arr)
n = (2, 1)
th_z = KTH.tile(arr_th, n)
th_rep = KTH.eval(th_z)
tf_rep = KTF.eval(KTF.tile(arr_tf, n))
assert_allclose(tf_rep, th_rep, atol=1e-05)
if hasattr(th_z, '_keras_shape'):
assert th_z._keras_shape == th_rep.shape
def test_tile(self):
shape = (3, 4)
arr = np.arange(np.prod(shape)).reshape(shape)
arr_th = KTH.variable(arr)
arr_tf = KTF.variable(arr)
n = (2, 1)
th_z = KTH.tile(arr_th, n)
th_rep = KTH.eval(th_z)
tf_rep = KTF.eval(KTF.tile(arr_tf, n))
assert_allclose(tf_rep, th_rep, atol=1e-05)
if hasattr(th_z, '_keras_shape'):
assert th_z._keras_shape == th_rep.shape
# test theano shape inference when
# input shape has None entries
if K.backend() == 'theano':
x = K.placeholder(shape=(None, 4))
n = 2
y = KTH.tile(x, n)
assert y._keras_shape == (None, 8)
n = (4, 3)
y = K.tile(x, n)
assert y._keras_shape == (None, 12)
def test_tile(self):
shape = (3, 4)
arr = np.arange(np.prod(shape)).reshape(shape)
arr_th = KTH.variable(arr)
arr_tf = KTF.variable(arr)
n = (2, 1)
th_z = KTH.tile(arr_th, n)
th_rep = KTH.eval(th_z)
tf_rep = KTF.eval(KTF.tile(arr_tf, n))
assert_allclose(tf_rep, th_rep, atol=1e-05)
if hasattr(th_z, '_keras_shape'):
assert th_z._keras_shape == th_rep.shape
# test theano shape inference when
# input shape has None entries
if K.backend() == 'theano':
x = K.placeholder(shape=(None, 4))
n = 2
y = KTH.tile(x, n)
assert y._keras_shape == (None, 8)
n = (4, 3)
y = K.tile(x, n)
assert y._keras_shape == (None, 12)
def call(self,
inputs,
initial_state=None,
initial_readout=None,
ground_truth=None,
mask=None,
training=None):
# input shape: `(samples, time (padded with zeros), input_dim)`
# note that the .build() method of subclasses MUST define
# self.input_spec and self.state_spec with complete input shapes.
if type(mask) is list:
mask = mask[0]
if self.model is None:
raise Exception('Empty RecurrentModel.')
num_req_states = self.num_states
if self.readout:
num_actual_states = num_req_states - 1
else:
num_actual_states = num_req_states
if type(inputs) is list:
inputs_list = inputs[:]
inputs = inputs_list.pop(0)
initial_states = inputs_list[:num_actual_states]
if len(initial_states) > 0:
if self._is_optional_input_placeholder(initial_states[0]):
initial_states = self.get_initial_state(inputs)
inputs_list = inputs_list[num_actual_states:]
if self.readout:
initial_readout = inputs_list.pop(0)
if self.teacher_force:
ground_truth = inputs_list.pop()
else:
if initial_state is not None:
if not isinstance(initial_state, (list, tuple)):
initial_states = [initial_state]
else:
initial_states = list(initial_state)
if self._is_optional_input_placeholder(initial_states[0]):
initial_states = self.get_initial_state(inputs)
elif self.stateful:
initial_states = self.states
else:
initial_states = self.get_initial_state(inputs)
if self.readout:
if initial_readout is None or self._is_optional_input_placeholder(
initial_readout):
output_shape = K.int_shape(_to_list((self.model.output))[0])
output_ndim = len(output_shape)
input_ndim = K.ndim(inputs)
initial_readout = K.zeros_like(inputs)
slices = [slice(None)] + [0] * (input_ndim - 1)
initial_readout = initial_readout[slices] # (batch_size,)
initial_readout = K.reshape(initial_readout,
(-1, ) + (1, ) * (output_ndim - 1))
initial_readout = K.tile(initial_readout,
(1, ) + tuple(output_shape[1:]))
initial_states.append(initial_readout)
if self.teacher_force:
if ground_truth is None or self._is_optional_input_placeholder(
ground_truth):
raise Exception(
'ground_truth must be provided for RecurrentModel with teacher_force=True.'
)
if K.backend() == 'tensorflow':
with tf.control_dependencies(None):
counter = K.zeros((1, ))
else:
counter = K.zeros((1, ))
counter = K.cast(counter, 'int32')
initial_states.insert(-1, counter)
initial_states[-2]
initial_states.insert(-1, ground_truth)
num_req_states += 2
if len(initial_states) != num_req_states:
raise ValueError('Layer requires ' + str(num_req_states) +
' states but was passed ' +
str(len(initial_states)) + ' initial states.')
input_shape = K.int_shape(inputs)
if self.unroll and input_shape[1] is None:
raise ValueError('Cannot unroll a RNN if the '
'time dimension is undefined. \n'
'- If using a Sequential model, '
'specify the time dimension by passing '
'an `input_shape` or `batch_input_shape` '
'argument to your first layer. If your '
'first layer is an Embedding, you can '
'also use the `input_length` argument.\n'
'- If using the functional API, specify '
'the time dimension by passing a `shape` '
'or `batch_shape` argument to your Input layer.')
preprocessed_input = self.preprocess_input(inputs, training=None)
constants = self.get_constants(inputs, training=None)
if self.decode:
initial_states.insert(0, inputs)
preprocessed_input = K.zeros((1, self.output_length, 1))
input_length = self.output_length
else:
input_length = input_shape[1]
if self.uses_learning_phase:
with learning_phase_scope(0):
last_output_test, outputs_test, states_test, updates = rnn(
self.step,
preprocessed_input,
initial_states,
go_backwards=self.go_backwards,
mask=mask,
constants=constants,
unroll=self.unroll,
input_length=input_length)
with learning_phase_scope(1):
last_output_train, outputs_train, states_train, updates = rnn(
self.step,
preprocessed_input,
initial_states,
go_backwards=self.go_backwards,
mask=mask,
constants=constants,
unroll=self.unroll,
input_length=input_length)
last_output = K.in_train_phase(last_output_train,
last_output_test,
training=training)
outputs = K.in_train_phase(outputs_train,
outputs_test,
training=training)
states = []
for state_train, state_test in zip(states_train, states_test):
states.append(
K.in_train_phase(state_train,
state_test,
training=training))
else:
last_output, outputs, states, updates = rnn(
self.step,
preprocessed_input,
initial_states,
go_backwards=self.go_backwards,
mask=mask,
constants=constants,
unroll=self.unroll,
input_length=input_length)
states = list(states)
if self.decode:
states.pop(0)
if self.readout:
states.pop()
if self.teacher_force:
states.pop()
states.pop()
if len(updates) > 0:
self.add_update(updates)
if self.stateful:
updates = []
for i in range(len(states)):
updates.append((self.states[i], states[i]))
self.add_update(updates, inputs)
# Properly set learning phase
if 0 < self.dropout + self.recurrent_dropout:
last_output._uses_learning_phase = True
outputs._uses_learning_phase = True
if self.return_sequences:
y = outputs
else:
y = last_output
if self.return_states:
return [y] + states
else:
return y
