def testSampleDistortedBoundingBoxShape(self):
with self.test_session():
image_size = constant_op.constant([40, 50, 1],
shape=[3],
dtype=dtypes.int32)
bounding_box = constant_op.constant([0.0, 0.0, 1.0, 1.0],
shape=[4],
dtype=dtypes.float32,)
begin, end, bbox_for_drawing = image_ops.sample_distorted_bounding_box(
image_size=image_size,
bounding_boxes=bounding_box,
min_object_covered=0.1,
aspect_ratio_range=(0.75, 1.33),
area_range=(0.05, 1.0))
# Test that the shapes are correct.
self.assertAllEqual([3], begin.get_shape().as_list())
self.assertAllEqual([3], end.get_shape().as_list())
self.assertAllEqual([1, 1, 4], bbox_for_drawing.get_shape().as_list())
def testSampleDistortedBoundingBoxShape(self):
with self.test_session():
image_size = constant_op.constant([40, 50, 1],
shape=[3],
dtype=dtypes.int32)
bounding_box = constant_op.constant([0.0, 0.0, 1.0, 1.0],
shape=[4],
dtype=dtypes.float32,)
begin, end, bbox_for_drawing = image_ops.sample_distorted_bounding_box(
image_size=image_size,
bounding_boxes=bounding_box,
min_object_covered=0.1,
aspect_ratio_range=(0.75, 1.33),
area_range=(0.05, 1.0))
# Test that the shapes are correct.
self.assertAllEqual([3], begin.get_shape().as_list())
self.assertAllEqual([3], end.get_shape().as_list())
self.assertAllEqual([1, 1, 4], bbox_for_drawing.get_shape().as_list())
def _testSampleDistortedBoundingBox(self, image, bounding_box,
min_object_covered, aspect_ratio_range,
area_range):
original_area = float(np.prod(image.shape))
bounding_box_area = float((bounding_box[3] - bounding_box[1]) *
(bounding_box[2] - bounding_box[0]))
image_size_np = np.array(image.shape, dtype=np.int32)
bounding_box_np = (np.array(bounding_box, dtype=np.float32)
.reshape([1, 1, 4]))
aspect_ratios = []
area_ratios = []
fraction_object_covered = []
num_iter = 1000
with self.test_session():
image_tf = constant_op.constant(image,
shape=image.shape)
image_size_tf = constant_op.constant(image_size_np,
shape=image_size_np.shape)
bounding_box_tf = constant_op.constant(bounding_box_np,
dtype=dtypes.float32,
shape=bounding_box_np.shape)
begin, end, _ = image_ops.sample_distorted_bounding_box(
image_size=image_size_tf,
bounding_boxes=bounding_box_tf,
min_object_covered=min_object_covered,
aspect_ratio_range=aspect_ratio_range,
area_range=area_range)
y = array_ops.slice(image_tf, begin, end)
for _ in xrange(num_iter):
y_tf = y.eval()
crop_height = y_tf.shape[0]
crop_width = y_tf.shape[1]
aspect_ratio = float(crop_width) / float(crop_height)
area = float(crop_width * crop_height)
aspect_ratios.append(aspect_ratio)
area_ratios.append(area / original_area)
fraction_object_covered.append(float(np.sum(y_tf)) / bounding_box_area)
# Ensure that each entry is observed within 3 standard deviations.
# num_bins = 10
# aspect_ratio_hist, _ = np.histogram(aspect_ratios,
# bins=num_bins,
# range=aspect_ratio_range)
# mean = np.mean(aspect_ratio_hist)
# stddev = np.sqrt(mean)
# TODO(wicke, shlens, dga): Restore this test so that it is no longer flaky.
# TODO(irving): Since the rejection probability is not independent of the
# aspect ratio, the aspect_ratio random value is not exactly uniformly
# distributed in [min_aspect_ratio, max_aspect_ratio). This test should be
# fixed to reflect the true statistical property, then tightened to enforce
# a stricter bound. Or, ideally, the sample_distorted_bounding_box Op
# be fixed to not use rejection sampling and generate correctly uniform
# aspect ratios.
# self.assertAllClose(aspect_ratio_hist,
# [mean] * num_bins, atol=3.6 * stddev)
# The resulting crop will not be uniformly distributed in area. In practice,
# we find that the area skews towards the small sizes. Instead, we perform
# a weaker test to ensure that the area ratios are merely within the
# specified bounds.
self.assertLessEqual(max(area_ratios), area_range[1])
self.assertGreaterEqual(min(area_ratios), area_range[0])
# For reference, here is what the distribution of area ratios look like.
area_ratio_hist, _ = np.histogram(area_ratios, bins=10, range=area_range)
print('area_ratio_hist ', area_ratio_hist)
def _testSampleDistortedBoundingBox(self, image, bounding_box,
min_object_covered, aspect_ratio_range,
area_range):
original_area = float(np.prod(image.shape))
bounding_box_area = float((bounding_box[3] - bounding_box[1]) *
(bounding_box[2] - bounding_box[0]))
image_size_np = np.array(image.shape, dtype=np.int32)
bounding_box_np = (np.array(bounding_box, dtype=np.float32)
.reshape([1, 1, 4]))
aspect_ratios = []
area_ratios = []
fraction_object_covered = []
num_iter = 1000
with self.test_session():
image_tf = constant_op.constant(image,
shape=image.shape)
image_size_tf = constant_op.constant(image_size_np,
shape=image_size_np.shape)
bounding_box_tf = constant_op.constant(bounding_box_np,
dtype=dtypes.float32,
shape=bounding_box_np.shape)
begin, end, _ = image_ops.sample_distorted_bounding_box(
image_size=image_size_tf,
bounding_boxes=bounding_box_tf,
min_object_covered=min_object_covered,
aspect_ratio_range=aspect_ratio_range,
area_range=area_range)
y = array_ops.slice(image_tf, begin, end)
for _ in xrange(num_iter):
y_tf = y.eval()
crop_height = y_tf.shape[0]
crop_width = y_tf.shape[1]
aspect_ratio = float(crop_width) / float(crop_height)
area = float(crop_width * crop_height)
aspect_ratios.append(aspect_ratio)
area_ratios.append(area / original_area)
fraction_object_covered.append(float(np.sum(y_tf)) / bounding_box_area)
# Ensure that each entry is observed within 3 standard deviations.
# num_bins = 10
# aspect_ratio_hist, _ = np.histogram(aspect_ratios,
# bins=num_bins,
# range=aspect_ratio_range)
# mean = np.mean(aspect_ratio_hist)
# stddev = np.sqrt(mean)
# TODO(wicke, shlens, dga): Restore this test so that it is no longer flaky.
# TODO(irving): Since the rejection probability is not independent of the
# aspect ratio, the aspect_ratio random value is not exactly uniformly
# distributed in [min_aspect_ratio, max_aspect_ratio). This test should be
# fixed to reflect the true statistical property, then tightened to enforce
# a stricter bound. Or, ideally, the sample_distorted_bounding_box Op
# be fixed to not use rejection sampling and generate correctly uniform
# aspect ratios.
# self.assertAllClose(aspect_ratio_hist,
# [mean] * num_bins, atol=3.6 * stddev)
# The resulting crop will not be uniformly distributed in area. In practice,
# we find that the area skews towards the small sizes. Instead, we perform
# a weaker test to ensure that the area ratios are merely within the
# specified bounds.
self.assertLessEqual(max(area_ratios), area_range[1])
self.assertGreaterEqual(min(area_ratios), area_range[0])
# For reference, here is what the distribution of area ratios look like.
area_ratio_hist, _ = np.histogram(area_ratios, bins=10, range=area_range)
print('area_ratio_hist ', area_ratio_hist)
