From 026bc91eae3078b0fa0463615bec0fa171ceb8a3 Mon Sep 17 00:00:00 2001
From: "A. Unique TensorFlower" <gardener@tensorflow.org>
Date: Wed, 19 Jun 2019 21:27:36 -0700
Subject: [PATCH] Adding radial constraint for Conv2D kernels to make them
rotation invariant.
PiperOrigin-RevId: 254129632
---
tensorflow/python/keras/constraints.py | 82 +++++++++++++++++++
tensorflow/python/keras/constraints_test.py | 18 ++++
...keras.constraints.-radial-constraint.pbtxt | 13 +++
.../v1/tensorflow.keras.constraints.pbtxt | 8 ++
....keras.constraints.radial_constraint.pbtxt | 13 +++
...keras.constraints.-radial-constraint.pbtxt | 13 +++
.../v2/tensorflow.keras.constraints.pbtxt | 8 ++
....keras.constraints.radial_constraint.pbtxt | 13 +++
8 files changed, 168 insertions(+)
create mode 100644 tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.-radial-constraint.pbtxt
create mode 100644 tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.radial_constraint.pbtxt
create mode 100644 tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.-radial-constraint.pbtxt
create mode 100644 tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.radial_constraint.pbtxt
diff --git a/tensorflow/python/keras/constraints.py b/tensorflow/python/keras/constraints.py
index 334d072d5a2..043ceb8dd6d 100644
--- a/tensorflow/python/keras/constraints.py
+++ b/tensorflow/python/keras/constraints.py
@@ -21,9 +21,12 @@ from __future__ import print_function
import six
+from tensorflow.python.framework import tensor_shape
from tensorflow.python.keras import backend as K
from tensorflow.python.keras.utils.generic_utils import deserialize_keras_object
from tensorflow.python.keras.utils.generic_utils import serialize_keras_object
+from tensorflow.python.ops import array_ops
+from tensorflow.python.ops import control_flow_ops
from tensorflow.python.ops import math_ops
from tensorflow.python.util.tf_export import keras_export
@@ -168,12 +171,91 @@ class MinMaxNorm(Constraint):
}
+@keras_export('keras.constraints.RadialConstraint',
+ 'keras.constraints.radial_constraint')
+class RadialConstraint(Constraint):
+ """Constrains `Conv2D` kernel weights to be the same for each radius.
+
+ For example, the desired output for the following 4-by-4 kernel::
+
+ ```
+ kernel = [[v_00, v_01, v_02, v_03],
+ [v_10, v_11, v_12, v_13],
+ [v_20, v_21, v_22, v_23],
+ [v_30, v_31, v_32, v_33]]
+ ```
+
+ is this::
+
+ ```
+ kernel = [[v_11, v_11, v_11, v_11],
+ [v_11, v_33, v_33, v_11],
+ [v_11, v_33, v_33, v_11],
+ [v_11, v_11, v_11, v_11]]
+ ```
+
+ This constraint can be applied to any `Conv2D` layer version, including
+ `Conv2DTranspose` and `SeparableConv2D`, and with either `"channels_last"` or
+ `"channels_first"` data format. The method assumes the weight tensor is of
+ shape `(rows, cols, input_depth, output_depth)`.
+ """
+
+ def __call__(self, w):
+ w_shape = w.shape
+ if w_shape.rank is None or w_shape.rank != 4:
+ raise ValueError(
+ 'The weight tensor must be of rank 4, but is of shape: %s' % w_shape)
+
+ height, width, channels, kernels = w_shape
+ w = K.reshape(w, (height, width, channels * kernels))
+ # TODO(cpeter): Switch map_fn for a faster tf.vectorized_map once K.switch
+ # is supported.
+ w = K.map_fn(
+ self._kernel_constraint,
+ K.stack(array_ops.unstack(w, axis=-1), axis=0))
+ return K.reshape(K.stack(array_ops.unstack(w, axis=0), axis=-1),
+ (height, width, channels, kernels))
+
+ def _kernel_constraint(self, kernel):
+ """Radially constraints a kernel with shape (height, width, channels)."""
+ padding = K.constant([[1, 1], [1, 1]], dtype='int32')
+
+ kernel_shape = K.shape(kernel)[0]
+ start = K.cast(kernel_shape / 2, 'int32')
+
+ kernel_new = K.switch(
+ K.cast(math_ops.floormod(kernel_shape, 2), 'bool'),
+ lambda: kernel[start - 1:start, start - 1:start],
+ lambda: kernel[start - 1:start, start - 1:start] + K.zeros( # pylint: disable=g-long-lambda
+ (2, 2), dtype=kernel.dtype))
+ index = K.switch(
+ K.cast(math_ops.floormod(kernel_shape, 2), 'bool'),
+ lambda: K.constant(0, dtype='int32'),
+ lambda: K.constant(1, dtype='int32'))
+ while_condition = lambda index, *args: K.less(index, start)
+
+ def body_fn(i, array):
+ return i + 1, array_ops.pad(
+ array,
+ padding,
+ constant_values=kernel[start + i, start + i])
+
+ _, kernel_new = control_flow_ops.while_loop(
+ while_condition,
+ body_fn,
+ [index, kernel_new],
+ shape_invariants=[index.get_shape(),
+ tensor_shape.TensorShape([None, None])])
+ return kernel_new
+
+
# Aliases.
max_norm = MaxNorm
non_neg = NonNeg
unit_norm = UnitNorm
min_max_norm = MinMaxNorm
+radial_constraint = RadialConstraint
# Legacy aliases.
maxnorm = max_norm
diff --git a/tensorflow/python/keras/constraints_test.py b/tensorflow/python/keras/constraints_test.py
index 92bc4852cff..741be34530a 100644
--- a/tensorflow/python/keras/constraints_test.py
+++ b/tensorflow/python/keras/constraints_test.py
@@ -18,6 +18,8 @@ from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
+import math
+
import numpy as np
from tensorflow.python import keras
@@ -36,6 +38,12 @@ def get_example_array():
return example_array
+def get_example_kernel(width):
+ np.random.seed(3537)
+ example_array = np.random.rand(width, width, 2, 2)
+ return example_array
+
+
@test_util.run_all_in_graph_and_eager_modes
class KerasConstraintsTest(test.TestCase):
@@ -93,6 +101,16 @@ class KerasConstraintsTest(test.TestCase):
assert not l2[l2 < m]
assert not l2[l2 > m * 2 + 1e-5]
+ def test_conv2d_radial_constraint(self):
+ for width in (3, 4, 5, 6):
+ array = get_example_kernel(width)
+ norm_instance = keras.constraints.radial_constraint()
+ normed = norm_instance(keras.backend.variable(array))
+ value = keras.backend.eval(normed)
+ assert np.all(value.shape == array.shape)
+ assert np.all(value[0:, 0, 0, 0] == value[-1:, 0, 0, 0])
+ assert len(set(value[..., 0, 0].flatten())) == math.ceil(float(width) / 2)
+
if __name__ == '__main__':
test.main()
diff --git a/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.-radial-constraint.pbtxt b/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.-radial-constraint.pbtxt
new file mode 100644
index 00000000000..826cfb92932
--- /dev/null
+++ b/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.-radial-constraint.pbtxt
@@ -0,0 +1,13 @@
+path: "tensorflow.keras.constraints.RadialConstraint"
+tf_class {
+ is_instance: "<class \'tensorflow.python.keras.constraints.RadialConstraint\'>"
+ is_instance: "<class \'tensorflow.python.keras.constraints.Constraint\'>"
+ is_instance: "<type \'object\'>"
+ member_method {
+ name: "__init__"
+ }
+ member_method {
+ name: "get_config"
+ argspec: "args=[\'self\'], varargs=None, keywords=None, defaults=None"
+ }
+}
diff --git a/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.pbtxt b/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.pbtxt
index 655685956f0..29444ef3405 100644
--- a/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.pbtxt
+++ b/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.pbtxt
@@ -16,6 +16,10 @@ tf_module {
name: "NonNeg"
mtype: "<type \'type\'>"
}
+ member {
+ name: "RadialConstraint"
+ mtype: "<type \'type\'>"
+ }
member {
name: "UnitNorm"
mtype: "<type \'type\'>"
@@ -32,6 +36,10 @@ tf_module {
name: "non_neg"
mtype: "<type \'type\'>"
}
+ member {
+ name: "radial_constraint"
+ mtype: "<type \'type\'>"
+ }
member {
name: "unit_norm"
mtype: "<type \'type\'>"
diff --git a/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.radial_constraint.pbtxt b/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.radial_constraint.pbtxt
new file mode 100644
index 00000000000..3040111b324
--- /dev/null
+++ b/tensorflow/tools/api/golden/v1/tensorflow.keras.constraints.radial_constraint.pbtxt
@@ -0,0 +1,13 @@
+path: "tensorflow.keras.constraints.radial_constraint"
+tf_class {
+ is_instance: "<class \'tensorflow.python.keras.constraints.RadialConstraint\'>"
+ is_instance: "<class \'tensorflow.python.keras.constraints.Constraint\'>"
+ is_instance: "<type \'object\'>"
+ member_method {
+ name: "__init__"
+ }
+ member_method {
+ name: "get_config"
+ argspec: "args=[\'self\'], varargs=None, keywords=None, defaults=None"
+ }
+}
diff --git a/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.-radial-constraint.pbtxt b/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.-radial-constraint.pbtxt
new file mode 100644
index 00000000000..826cfb92932
--- /dev/null
+++ b/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.-radial-constraint.pbtxt
@@ -0,0 +1,13 @@
+path: "tensorflow.keras.constraints.RadialConstraint"
+tf_class {
+ is_instance: "<class \'tensorflow.python.keras.constraints.RadialConstraint\'>"
+ is_instance: "<class \'tensorflow.python.keras.constraints.Constraint\'>"
+ is_instance: "<type \'object\'>"
+ member_method {
+ name: "__init__"
+ }
+ member_method {
+ name: "get_config"
+ argspec: "args=[\'self\'], varargs=None, keywords=None, defaults=None"
+ }
+}
diff --git a/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.pbtxt b/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.pbtxt
index 655685956f0..29444ef3405 100644
--- a/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.pbtxt
+++ b/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.pbtxt
@@ -16,6 +16,10 @@ tf_module {
name: "NonNeg"
mtype: "<type \'type\'>"
}
+ member {
+ name: "RadialConstraint"
+ mtype: "<type \'type\'>"
+ }
member {
name: "UnitNorm"
mtype: "<type \'type\'>"
@@ -32,6 +36,10 @@ tf_module {
name: "non_neg"
mtype: "<type \'type\'>"
}
+ member {
+ name: "radial_constraint"
+ mtype: "<type \'type\'>"
+ }
member {
name: "unit_norm"
mtype: "<type \'type\'>"
diff --git a/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.radial_constraint.pbtxt b/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.radial_constraint.pbtxt
new file mode 100644
index 00000000000..3040111b324
--- /dev/null
+++ b/tensorflow/tools/api/golden/v2/tensorflow.keras.constraints.radial_constraint.pbtxt
@@ -0,0 +1,13 @@
+path: "tensorflow.keras.constraints.radial_constraint"
+tf_class {
+ is_instance: "<class \'tensorflow.python.keras.constraints.RadialConstraint\'>"
+ is_instance: "<class \'tensorflow.python.keras.constraints.Constraint\'>"
+ is_instance: "<type \'object\'>"
+ member_method {
+ name: "__init__"
+ }
+ member_method {
+ name: "get_config"
+ argspec: "args=[\'self\'], varargs=None, keywords=None, defaults=None"
+ }
+}