Generate a single randomly distorted bounding box for an image.
Bounding box annotations are often supplied in addition to ground-truth labels in image recognition or object localization tasks. A common technique for training such a system is to randomly distort an image while preserving its content, i.e. data augmentation. This Op outputs a randomly distorted localization of an object, i.e. bounding box, given an `image_size`, `bounding_boxes` and a series of constraints.
The output of this Op is a single bounding box that may be used to crop the
original image. The output is returned as 3 tensors: `begin`, `size` and
`bboxes`. The first 2 tensors can be fed directly into tf.slice
to crop the
image. The latter may be supplied to tf.image.draw_bounding_boxes
to visualize
what the bounding box looks like.
Bounding boxes are supplied and returned as `[y_min, x_min, y_max, x_max]`. The bounding box coordinates are floats in `[0.0, 1.0]` relative to the width and height of the underlying image.
For example,
# Generate a single distorted bounding box.
begin, size, bbox_for_draw = tf.image.sample_distorted_bounding_box(
tf.shape(image),
bounding_boxes=bounding_boxes)
# Draw the bounding box in an image summary.
image_with_box = tf.image.draw_bounding_boxes(tf.expand_dims(image, 0),
bbox_for_draw)
tf.summary.image('images_with_box', image_with_box)
# Employ the bounding box to distort the image.
distorted_image = tf.slice(image, begin, size)
Nested Classes
class | SampleDistortedBoundingBox.Options | Optional attributes for SampleDistortedBoundingBox
|
Constants
String | OP_NAME | The name of this op, as known by TensorFlow core engine |
Public Methods
static SampleDistortedBoundingBox.Options |
areaRange(List<Float> areaRange)
|
static SampleDistortedBoundingBox.Options |
aspectRatioRange(List<Float> aspectRatioRange)
|
Output<TFloat32> |
bboxes()
3-D with shape `[1, 1, 4]` containing the distorted bounding box.
|
Output<T> |
begin()
1-D, containing `[offset_height, offset_width, 0]`.
|
static <T extends TNumber> SampleDistortedBoundingBox<T> | |
static SampleDistortedBoundingBox.Options |
maxAttempts(Long maxAttempts)
|
static SampleDistortedBoundingBox.Options |
seed(Long seed)
|
static SampleDistortedBoundingBox.Options |
seed2(Long seed2)
|
Output<T> |
size()
1-D, containing `[target_height, target_width, -1]`.
|
static SampleDistortedBoundingBox.Options |
useImageIfNoBoundingBoxes(Boolean useImageIfNoBoundingBoxes)
|
Inherited Methods
Constants
public static final String OP_NAME
The name of this op, as known by TensorFlow core engine
Public Methods
public static SampleDistortedBoundingBox.Options areaRange (List<Float> areaRange)
Parameters
areaRange | The cropped area of the image must contain a fraction of the supplied image within this range. |
---|
public static SampleDistortedBoundingBox.Options aspectRatioRange (List<Float> aspectRatioRange)
Parameters
aspectRatioRange | The cropped area of the image must have an aspect ratio = width / height within this range. |
---|
public Output<TFloat32> bboxes ()
3-D with shape `[1, 1, 4]` containing the distorted bounding box.
Provide as input to tf.image.draw_bounding_boxes
.
public Output<T> begin ()
1-D, containing `[offset_height, offset_width, 0]`. Provide as input to
tf.slice
.
public static SampleDistortedBoundingBox<T> create (Scope scope, Operand<T> imageSize, Operand<TFloat32> boundingBoxes, Operand<TFloat32> minObjectCovered, Options... options)
Factory method to create a class wrapping a new SampleDistortedBoundingBox operation.
Parameters
scope | current scope |
---|---|
imageSize | 1-D, containing `[height, width, channels]`. |
boundingBoxes | 3-D with shape `[batch, N, 4]` describing the N bounding boxes associated with the image. |
minObjectCovered | The cropped area of the image must contain at least this fraction of any bounding box supplied. The value of this parameter should be non-negative. In the case of 0, the cropped area does not need to overlap any of the bounding boxes supplied. |
options | carries optional attributes values |
Returns
- a new instance of SampleDistortedBoundingBox
public static SampleDistortedBoundingBox.Options maxAttempts (Long maxAttempts)
Parameters
maxAttempts | Number of attempts at generating a cropped region of the image of the specified constraints. After `max_attempts` failures, return the entire image. |
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public static SampleDistortedBoundingBox.Options seed (Long seed)
Parameters
seed | If either `seed` or `seed2` are set to non-zero, the random number generator is seeded by the given `seed`. Otherwise, it is seeded by a random seed. |
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public static SampleDistortedBoundingBox.Options seed2 (Long seed2)
Parameters
seed2 | A second seed to avoid seed collision. |
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public Output<T> size ()
1-D, containing `[target_height, target_width, -1]`. Provide as input to
tf.slice
.
public static SampleDistortedBoundingBox.Options useImageIfNoBoundingBoxes (Boolean useImageIfNoBoundingBoxes)
Parameters
useImageIfNoBoundingBoxes | Controls behavior if no bounding boxes supplied. If true, assume an implicit bounding box covering the whole input. If false, raise an error. |
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