StatelessSampleDistortedBoundingBox

Generate a randomly distorted bounding box for an image deterministically.

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, given the same `seed`, deterministically 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 the height of the underlying image.

The output of this Op is guaranteed to be the same given the same `seed` and is independent of how many times the function is called, and independent of global seed settings (e.g. tf.random.set_seed).

Example usage:

>>> image = np.array([[[1], [2], [3]], [[4], [5], [6]], [[7], [8], [9]]]) >>> bbox = tf.constant( ... [0.0, 0.0, 1.0, 1.0], dtype=tf.float32, shape=[1, 1, 4]) >>> seed = (1, 2) >>> # Generate a single distorted bounding box. >>> bbox_begin, bbox_size, bbox_draw = ( ... tf.image.stateless_sample_distorted_bounding_box( ... tf.shape(image), bounding_boxes=bbox, seed=seed)) >>> # Employ the bounding box to distort the image. >>> tf.slice(image, bbox_begin, bbox_size) >>> # Draw the bounding box in an image summary. >>> colors = np.array([[1.0, 0.0, 0.0], [0.0, 0.0, 1.0]]) >>> tf.image.draw_bounding_boxes( ... tf.expand_dims(tf.cast(image, tf.float32),0), bbox_draw, colors)

Note that if no bounding box information is available, setting `use_image_if_no_bounding_boxes = true` will assume there is a single implicit bounding box covering the whole image. If `use_image_if_no_bounding_boxes` is false and no bounding boxes are supplied, an error is raised.