cvpods.structures package

class cvpods.structures.Boxes(tensor: torch.Tensor)

Bases: object

This structure stores a list of boxes as a Nx4 torch.Tensor. It supports some common methods about boxes (area, clip, nonempty, etc), and also behaves like a Tensor (support indexing, to(device), .device, and iteration over all boxes)

tensor

float matrix of Nx4.

Type

torch.Tensor

BoxSizeType = typing.Union[typing.List[int], typing.Tuple[int, int]]

__init__(tensor: torch.Tensor)

Parameters

tensor (Tensor[float]) – a Nx4 matrix. Each row is (x1, y1, x2, y2).

clone() → cvpods.structures.boxes.Boxes

Clone the Boxes.

Returns

Boxes

to(device: str) → cvpods.structures.boxes.Boxes

area() → torch.Tensor

Computes the area of all the boxes.

Returns

torch.Tensor – a vector with areas of each box.

clip(box_size: Union[List[int], Tuple[int, int]]) → None

Clip (in place) the boxes by limiting x coordinates to the range [0, width] and y coordinates to the range [0, height].

Parameters

box_size (height, width) – The clipping box’s size.

nonempty(threshold: int = 0) → torch.Tensor

Find boxes that are non-empty. A box is considered empty, if either of its side is no larger than threshold.

Returns

Tensor – a binary vector which represents whether each box is empty (False) or non-empty (True).

__getitem__(item: Union[int, slice, torch.BoolTensor]) → cvpods.structures.boxes.Boxes

Returns

Boxes – Create a new Boxes by indexing.

The following usage are allowed:

1. new_boxes = boxes[3]: return a Boxes which contains only one box.

2. new_boxes = boxes[2:10]: return a slice of boxes.

3. new_boxes = boxes[vector], where vector is a torch.BoolTensor with length = len(boxes). Nonzero elements in the vector will be selected.

Note that the returned Boxes might share storage with this Boxes, subject to Pytorch’s indexing semantics.

inside_box(box_size: Union[List[int], Tuple[int, int]], boundary_threshold: int = 0) → torch.Tensor

Parameters

• box_size (height, width) – Size of the reference box.

• boundary_threshold (int) – Boxes that extend beyond the reference box boundary by more than boundary_threshold are considered “outside”.

Returns

a binary vector, indicating whether each box is inside the reference box.

get_centers() → torch.Tensor

Returns

The box centers in a Nx2 array of (x, y).

scale(scale_x: float, scale_y: float) → None

Scale the box with horizontal and vertical scaling factors

classmethod cat(boxes_list: List[Boxes]) → cvpods.structures.boxes.Boxes

Concatenates a list of Boxes into a single Boxes

Parameters

boxes_list (list[Boxes]) –

Returns

Boxes – the concatenated Boxes

property device

__iter__() → Iterator[torch.Tensor]

Yield a box as a Tensor of shape (4,) at a time.

class cvpods.structures.BoxMode

Bases: enum.IntEnum

Enum of different ways to represent a box.

XYXY_ABS

(x0, y0, x1, y1) in absolute floating points coordinates. The coordinates in range [0, width or height].

XYWH_ABS

(x0, y0, w, h) in absolute floating points coordinates.

XYXY_REL

(x0, y0, x1, y1) in range [0, 1]. They are relative to the size of the image.

XYWH_REL

(x0, y0, w, h) in range [0, 1]. They are relative to the size of the image.

XYWHA_ABS

(xc, yc, w, h, a) in absolute floating points coordinates. (xc, yc) is the center of the rotated box, and the angle a is in degrees ccw.

XYXY_ABS = 0

XYWH_ABS = 1

XYXY_REL = 2

XYWH_REL = 3

XYWHA_ABS = 4

static convert(box: Union[List[float], Tuple[float, …], torch.Tensor, numpy.ndarray], from_mode: cvpods.structures.boxes.BoxMode, to_mode: cvpods.structures.boxes.BoxMode) → Union[List[float], Tuple[float, …], torch.Tensor, numpy.ndarray]

Parameters

• box – can be a k-tuple, k-list or an Nxk array/tensor, where k = 4 or 5

• to_mode (from_mode,) –

Returns

The converted box of the same type.

cvpods.structures.pairwise_ioa(gt: cvpods.structures.boxes.Boxes, boxes: cvpods.structures.boxes.Boxes, labels, ignore_label=- 1) → torch.Tensor

Given two lists of boxes of size N and M, compute the IoU (intersection over union) between __all__ N x M pairs of boxes. The box order must be (xmin, ymin, xmax, ymax).

Parameters

boxes1,boxes2 (Boxes) – two Boxes. Contains N & M boxes, respectively.

Returns

Tensor – IoU, sized [N,M].

cvpods.structures.pairwise_iou(boxes1: cvpods.structures.boxes.Boxes, boxes2: cvpods.structures.boxes.Boxes) → torch.Tensor

Given two lists of boxes of size N and M, compute the IoU (intersection over union) between __all__ N x M pairs of boxes. The box order must be (xmin, ymin, xmax, ymax).

Parameters

boxes1,boxes2 (Boxes) – two Boxes. Contains N & M boxes, respectively.

Returns

Tensor – IoU, sized [N,M].

class cvpods.structures.ImageList(tensor: torch.Tensor, image_sizes: List[Tuple[int, int]])

Bases: object

Structure that holds a list of images (of possibly varying sizes) as a single tensor. This works by padding the images to the same size, and storing in a field the original sizes of each image

image_sizes

each tuple is (h, w)

Type

list[tuple[int, int]]

__init__(tensor: torch.Tensor, image_sizes: List[Tuple[int, int]])

Parameters

• tensor (Tensor) – of shape (N, H, W) or (N, C_1, …, C_K, H, W) where K >= 1

• image_sizes (list[tuple[int, int]]) – Each tuple is (h, w).

__getitem__(idx: Union[int, slice]) → torch.Tensor

Access the individual image in its original size.

Returns

Tensor – an image of shape (H, W) or (C_1, …, C_K, H, W) where K >= 1

to(*args: Any, **kwargs: Any) → cvpods.structures.image_list.ImageList

property device

static from_tensors(tensors: Sequence[torch.Tensor], size_divisibility: int = 0, pad_ref_long: bool = False, pad_value: float = 0.0) → cvpods.structures.image_list.ImageList

Parameters

• tensors – a tuple or list of torch.Tensors, each of shape (Hi, Wi) or (C_1, …, C_K, Hi, Wi) where K >= 1. The Tensors will be padded with pad_value so that they will have the same shape.

• size_divisibility (int) – If size_divisibility > 0, also adds padding to ensure the common height and width is divisible by size_divisibility

• pad_value (float) – value to pad

Returns

an ImageList.

class cvpods.structures.Instances(image_size: Tuple[int, int], **kwargs: Any)

Bases: object

This class represents a list of instances in an image. It stores the attributes of instances (e.g., boxes, masks, labels, scores) as “fields”. All fields must have the same __len__ which is the number of instances.

All other (non-field) attributes of this class are considered private: they must start with ‘_’ and are not modifiable by a user.

Some basic usage:

1. Set/Get a field: .. code-block:: python

   instances.gt_boxes = Boxes(…) print(instances.pred_masks) # a tensor of shape (N, H, W) print(‘gt_masks’ in instances)

2. len(instances) returns the number of instances

3. Indexing: instances[indices] will apply the indexing on all the fields and returns a new Instances. Typically, indices is a integer vector of indices, or a binary mask of length num_instances,

__init__(image_size: Tuple[int, int], **kwargs: Any)

Parameters

• image_size (height, width) – the spatial size of the image.

• kwargs – fields to add to this Instances.

property image_size

Returns: tuple: height, width

set(name: str, value: Any) → None

Set the field named name to value. The length of value must be the number of instances, and must agree with other existing fields in this object.

has(name: str) → bool

Returns

bool – whether the field called name exists.

remove(name: str) → None

Remove the field called name.

get(name: str) → Any

Returns the field called name.

get_fields() → Dict[str, Any]

Returns

dict – a dict which maps names (str) to data of the fields

Modifying the returned dict will modify this instance.

to(device: str) → cvpods.structures.instances.Instances

Returns

Instances – all fields are called with a to(device), if the field has this method.

__getitem__(item: Union[int, slice, torch.BoolTensor]) → cvpods.structures.instances.Instances

Parameters

item – an index-like object and will be used to index all the fields.

Returns

If item is a string, return the data in the corresponding field. Otherwise, returns an Instances where all fields are indexed by item.

static cat(instance_lists: List[Instances]) → cvpods.structures.instances.Instances

Parameters

instance_lists (list[Instances]) –

Returns

Instances

class cvpods.structures.Keypoints(keypoints: Union[torch.Tensor, numpy.ndarray, List[List[float]]])

Bases: object

Stores keypoint annotation data. GT Instances have a gt_keypoints property containing the x,y location and visibility flag of each keypoint. This tensor has shape (N, K, 3) where N is the number of instances and K is the number of keypoints per instance.

The visibility flag follows the COCO format and must be one of three integers: * v=0: not labeled (in which case x=y=0) * v=1: labeled but not visible * v=2: labeled and visible

__init__(keypoints: Union[torch.Tensor, numpy.ndarray, List[List[float]]])

Parameters

• keypoints – A Tensor, numpy array, or list of the x, y, and visibility of each keypoint.

• shape should be (The) –

• and K is the number of keypoints per instance. (instances,) –

to(*args: Any, **kwargs: Any) → cvpods.structures.keypoints.Keypoints

property device

to_heatmap(boxes: torch.Tensor, heatmap_size: int) → torch.Tensor

Parameters

boxes – Nx4 tensor, the boxes to draw the keypoints to

Returns

heatmaps – A tensor of shape (N, K) containing an integer spatial label

in the range [0, heatmap_size**2 - 1] for each keypoint in the input.

valid:

A tensor of shape (N, K) containing whether each keypoint is in the roi or not.

__getitem__(item: Union[int, slice, torch.BoolTensor]) → cvpods.structures.keypoints.Keypoints

Create a new Keypoints by indexing on this Keypoints.

The following usage are allowed:

1. new_kpts = kpts[3]: return a Keypoints which contains only one instance.

2. new_kpts = kpts[2:10]: return a slice of key points.

3. new_kpts = kpts[vector], where vector is a torch.ByteTensor with length = len(kpts). Nonzero elements in the vector will be selected.

Note that the returned Keypoints might share storage with this Keypoints, subject to Pytorch’s indexing semantics.

cvpods.structures.heatmaps_to_keypoints(maps: torch.Tensor, rois: torch.Tensor) → torch.Tensor

Extract predicted keypoint locations from heatmaps. :param maps: (#ROIs, #keypoints, POOL_H, POOL_W). The predicted heatmap of logits for :type maps: Tensor :param each ROI and each keypoint.: :param rois: (#ROIs, 4). The box of each ROI. :type rois: Tensor

Returns

Tensor of shape (#ROIs, #keypoints, 4) with the last dimension corresponding to (x, y, logit, score) for each keypoint.

When converting discrete pixel indices in an NxN image to a continuous keypoint coordinate, we maintain consistency with Keypoints.to_heatmap() by using the conversion from Heckbert 1990: c = d + 0.5, where d is a discrete coordinate and c is a continuous coordinate.

class cvpods.structures.BitMasks(tensor: Union[torch.Tensor, numpy.ndarray])

Bases: object

This class stores the segmentation masks for all objects in one image, in the form of bitmaps.

tensor

bool Tensor of N,H,W, representing N instances in the image.

__init__(tensor: Union[torch.Tensor, numpy.ndarray])

Parameters

tensor – bool Tensor of N,H,W, representing N instances in the image.

to(device: str) → cvpods.structures.masks.BitMasks

property device

__getitem__(item: Union[int, slice, torch.BoolTensor]) → cvpods.structures.masks.BitMasks

Returns

BitMasks – Create a new BitMasks by indexing.

The following usage are allowed:

1. new_masks = masks[3]: return a BitMasks which contains only one mask.

2. new_masks = masks[2:10]: return a slice of masks.

3. new_masks = masks[vector], where vector is a torch.BoolTensor with length = len(masks). Nonzero elements in the vector will be selected.

Note that the returned object might share storage with this object, subject to Pytorch’s indexing semantics.

nonempty() → torch.Tensor

Find masks that are non-empty.

Returns

Tensor –

a BoolTensor which represents

whether each mask is empty (False) or non-empty (True).

static from_polygon_masks(polygon_masks: Union[PolygonMasks, List[List[numpy.ndarray]]], height: int, width: int) → cvpods.structures.masks.BitMasks

Parameters

• polygon_masks (list[list[ndarray]] or PolygonMasks) –

• width (height,) –

crop_and_resize(boxes: torch.Tensor, mask_size: int) → torch.Tensor

Crop each bitmask by the given box, and resize results to (mask_size, mask_size). This can be used to prepare training targets for Mask R-CNN. It has less reconstruction error compared to rasterization with polygons. However we observe no difference in accuracy, but BitMasks requires more memory to store all the masks.

Parameters

• boxes (Tensor) – Nx4 tensor storing the boxes for each mask

• mask_size (int) – the size of the rasterized mask.

Returns

Tensor – A bool tensor of shape (N, mask_size, mask_size), where N is the number of predicted boxes for this image.

get_bounding_boxes() → None

Returns

Boxes – tight bounding boxes around bit masks.

static cat(bitmasks_list: List[BitMasks]) → cvpods.structures.masks.BitMasks

Concatenates a list of BitMasks into a single BitMasks :param bitmasks_list: :type bitmasks_list: list[BitMasks]

Returns

BitMasks – the concatenated BitMasks

class cvpods.structures.PolygonMasks(polygons: List[List[Union[torch.Tensor, numpy.ndarray]]])

Bases: object

This class stores the segmentation masks for all objects in one image, in the form of polygons.

polygons

list[list[ndarray]]. Each ndarray is a float64 vector representing a polygon.

__init__(polygons: List[List[Union[torch.Tensor, numpy.ndarray]]])

Parameters

polygons (list[list[Tensor[float]]]) – The first level of the list correspond to individual instances, the second level to all the polygons that compose the instance, and the third level to the polygon coordinates. The third level Tensor should have the format of torch.Tensor([x0, y0, x1, y1, …, xn, yn]) (n >= 3).

to(device: str) → cvpods.structures.masks.PolygonMasks

property device

get_bounding_boxes() → cvpods.structures.boxes.Boxes

Returns

Boxes – tight bounding boxes around polygon masks.

nonempty() → torch.Tensor

Find masks that are non-empty.

Returns

Tensor – a BoolTensor which represents whether each mask is empty (False) or not (True).

__getitem__(item: Union[int, slice, List[int], torch.BoolTensor]) → cvpods.structures.masks.PolygonMasks

Support indexing over the instances and return a PolygonMasks object. item can be:

1. An integer. It will return an object with only one instance.

2. A slice. It will return an object with the selected instances.

3. A list[int]. It will return an object with the selected instances, correpsonding to the indices in the list.

4. A vector mask of type BoolTensor, whose length is num_instances. It will return an object with the instances whose mask is nonzero.

__iter__() → Iterator[List[torch.Tensor]]

Yields

list[ndarray] – the polygons for one instance. Each Tensor is a float64 vector representing a polygon.

crop_and_resize(boxes: torch.Tensor, mask_size: int) → torch.Tensor

Crop each mask by the given box, and resize results to (mask_size, mask_size). This can be used to prepare training targets for Mask R-CNN.

Parameters

• boxes (Tensor) – Nx4 tensor storing the boxes for each mask

• mask_size (int) – the size of the rasterized mask.

Returns

Tensor – A bool tensor of shape (N, mask_size, mask_size), where N is the number of predicted boxes for this image.

area()

Computes area of the mask. Only works with Polygons, using the shoelace formula: https://stackoverflow.com/questions/24467972/calculate-area-of-polygon-given-x-y-coordinates :returns: Tensor – a vector, area for each instance

static cat(polymasks_list: List[PolygonMasks]) → cvpods.structures.masks.PolygonMasks

Concatenates a list of PolygonMasks into a single PolygonMasks :param polymasks_list: :type polymasks_list: list[PolygonMasks]

Returns

PolygonMasks – the concatenated PolygonMasks

cvpods.structures.polygons_to_bitmask(polygons: List[numpy.ndarray], height: int, width: int) → numpy.ndarray

Parameters

• polygons (list[ndarray]) – each array has shape (Nx2,)

• width (height,) –

Returns

ndarray – a bool mask of shape (height, width)

cvpods.structures.rasterize_polygons_within_box(polygons: List[numpy.ndarray], box: numpy.ndarray, mask_size: int) → torch.Tensor

Rasterize the polygons into a mask image and crop the mask content in the given box. The cropped mask is resized to (mask_size, mask_size).

This function is used when generating training targets for mask head in Mask R-CNN. Given original ground-truth masks for an image, new ground-truth mask training targets in the size of mask_size x mask_size must be provided for each predicted box. This function will be called to produce such targets.

Parameters

• polygons (list[ndarray[float]]) – a list of polygons, which represents an instance.

• box – 4-element numpy array

• mask_size (int) –

Returns

Tensor – BoolTensor of shape (mask_size, mask_size)

class cvpods.structures.RotatedBoxes(tensor: torch.Tensor)

Bases: cvpods.structures.boxes.Boxes

This structure stores a list of rotated boxes as a Nx5 torch.Tensor. It supports some common methods about boxes (area, clip, nonempty, etc), and also behaves like a Tensor (support indexing, to(device), .device, and iteration over all boxes)

__init__(tensor: torch.Tensor)

Parameters

tensor (Tensor[float]) – a Nx5 matrix. Each row is (x_center, y_center, width, height, angle), in which angle is represented in degrees. While there’s no strict range restriction for it, the recommended principal range is between [-180, 180) degrees.

Assume we have a horizontal box B = (x_center, y_center, width, height), where width is along the x-axis and height is along the y-axis. The rotated box B_rot (x_center, y_center, width, height, angle) can be seen as:

1. When angle == 0: B_rot == B

2. When angle > 0: B_rot is obtained by rotating B w.r.t its center by \(|angle|\) degrees CCW;

3. When angle < 0: B_rot is obtained by rotating B w.r.t its center by \(|angle|\) degrees CW.

Mathematically, since the right-handed coordinate system for image space is (y, x), where y is top->down and x is left->right, the 4 vertices of the rotated rectangle \((yr_i, xr_i)\) (i = 1, 2, 3, 4) can be obtained from the vertices of the horizontal rectangle (y_i, x_i) (i = 1, 2, 3, 4) in the following way (\(\theta = angle*\pi/180\) is the angle in radians, (y_c, x_c) is the center of the rectangle):

\[ \begin{align}\begin{aligned}yr_i = \cos(\theta) (y_i - y_c) - \sin(\theta) (x_i - x_c) + y_c,\\xr_i = \sin(\theta) (y_i - y_c) + \cos(\theta) (x_i - x_c) + x_c,\end{aligned}\end{align} \]

which is the standard rigid-body rotation transformation.

Intuitively, the angle is (1) the rotation angle from y-axis in image space to the height vector (top->down in the box’s local coordinate system) of the box in CCW, and (2) the rotation angle from x-axis in image space to the width vector (left->right in the box’s local coordinate system) of the box in CCW.

More intuitively, consider the following horizontal box ABCD represented in (x1, y1, x2, y2): (3, 2, 7, 4), covering the [3, 7] x [2, 4] region of the continuous coordinate system which looks like this:

O--------> x
|
|  A---B
|  |   |
|  D---C
|
v y

Note that each capital letter represents one 0-dimensional geometric point instead of a ‘square pixel’ here.

In the example above, using (x, y) to represent a point we have:

\[O = (0, 0), A = (3, 2), B = (7, 2), C = (7, 4), D = (3, 4)\]

We name vector AB = vector DC as the width vector in box’s local coordinate system, and vector AD = vector BC as the height vector in box’s local coordinate system. Initially, when angle = 0 degree, they’re aligned with the positive directions of x-axis and y-axis in the image space, respectively.

For better illustration, we denote the center of the box as E,

O--------> x
|
|  A---B
|  | E |
|  D---C
|
v y

where the center E = ((3+7)/2, (2+4)/2) = (5, 3).

Also,

\[width = |AB| = |CD| = 7 - 3 = 4, height = |AD| = |BC| = 4 - 2 = 2.\]

Therefore, the corresponding representation for the same shape in rotated box in (x_center, y_center, width, height, angle) format is:

(5, 3, 4, 2, 0),

Now, let’s consider (5, 3, 4, 2, 90), which is rotated by 90 degrees CCW (counter-clockwise) by definition. It looks like this:

O--------> x
|   B-C
|   | |
|   |E|
|   | |
|   A-D
v y

The center E is still located at the same point (5, 3), while the vertices ABCD are rotated by 90 degrees CCW with regard to E: A = (4, 5), B = (4, 1), C = (6, 1), D = (6, 5)

Here, 90 degrees can be seen as the CCW angle to rotate from y-axis to vector AD or vector BC (the top->down height vector in box’s local coordinate system), or the CCW angle to rotate from x-axis to vector AB or vector DC (the left->right width vector in box’s local coordinate system).

\[width = |AB| = |CD| = 5 - 1 = 4, height = |AD| = |BC| = 6 - 4 = 2.\]

Next, how about (5, 3, 4, 2, -90), which is rotated by 90 degrees CW (clockwise) by definition? It looks like this:

O--------> x
|   D-A
|   | |
|   |E|
|   | |
|   C-B
v y

The center E is still located at the same point (5, 3), while the vertices ABCD are rotated by 90 degrees CW with regard to E: A = (6, 1), B = (6, 5), C = (4, 5), D = (4, 1)

\[width = |AB| = |CD| = 5 - 1 = 4, height = |AD| = |BC| = 6 - 4 = 2.\]

This covers exactly the same region as (5, 3, 4, 2, 90) does, and their IoU will be 1. However, these two will generate different RoI Pooling results and should not be treated as an identical box.

On the other hand, it’s easy to see that (X, Y, W, H, A) is identical to (X, Y, W, H, A+360N), for any integer N. For example (5, 3, 4, 2, 270) would be identical to (5, 3, 4, 2, -90), because rotating the shape 270 degrees CCW is equivalent to rotating the same shape 90 degrees CW.

We could rotate further to get (5, 3, 4, 2, 180), or (5, 3, 4, 2, -180):

O--------> x
|
|  C---D
|  | E |
|  B---A
|
v y

\[ \begin{align}\begin{aligned}A = (7, 4), B = (3, 4), C = (3, 2), D = (7, 2),\\width = |AB| = |CD| = 7 - 3 = 4, height = |AD| = |BC| = 4 - 2 = 2.\end{aligned}\end{align} \]

Finally, this is a very inaccurate (heavily quantized) illustration of how (5, 3, 4, 2, 60) looks like in case anyone wonders:

O--------> x
|     B            |    /  C
|   /E /
|  A  /
|   `D
v y

It’s still a rectangle with center of (5, 3), width of 4 and height of 2, but its angle (and thus orientation) is somewhere between (5, 3, 4, 2, 0) and (5, 3, 4, 2, 90).

clone() → cvpods.structures.rotated_boxes.RotatedBoxes

Clone the RotatedBoxes.

Returns

RotatedBoxes

to(device: str) → cvpods.structures.rotated_boxes.RotatedBoxes

area() → torch.Tensor

Computes the area of all the boxes.

Returns

torch.Tensor – a vector with areas of each box.

normalize_angles() → None

Restrict angles to the range of [-180, 180) degrees

clip(box_size: Union[List[int], Tuple[int, int]], clip_angle_threshold: float = 1.0) → None

Clip (in place) the boxes by limiting x coordinates to the range [0, width] and y coordinates to the range [0, height].

For RRPN: Only clip boxes that are almost horizontal with a tolerance of clip_angle_threshold to maintain backward compatibility.

Rotated boxes beyond this threshold are not clipped for two reasons:

1. There are potentially multiple ways to clip a rotated box to make it fit within the image.

2. It’s tricky to make the entire rectangular box fit within the image and still be able to not leave out pixels of interest.

Therefore we rely on ops like RoIAlignRotated to safely handle this.

Parameters

• box_size (height, width) – The clipping box’s size.

• clip_angle_threshold – Iff. abs(normalized(angle)) <= clip_angle_threshold (in degrees), we do the clipping as horizontal boxes.

nonempty(threshold: int = 0) → torch.Tensor

Find boxes that are non-empty. A box is considered empty, if either of its side is no larger than threshold.

Returns

Tensor – a binary vector which represents whether each box is empty (False) or non-empty (True).

__getitem__(item: Union[int, slice, torch.BoolTensor]) → cvpods.structures.rotated_boxes.RotatedBoxes

Returns

RotatedBoxes – Create a new RotatedBoxes by indexing.

The following usage are allowed:

1. new_boxes = boxes[3]: return a RotatedBoxes which contains only one box.

2. new_boxes = boxes[2:10]: return a slice of boxes.

3. new_boxes = boxes[vector], where vector is a torch.ByteTensor with length = len(boxes). Nonzero elements in the vector will be selected.

Note that the returned RotatedBoxes might share storage with this RotatedBoxes, subject to Pytorch’s indexing semantics.

inside_box(box_size: Union[List[int], Tuple[int, int]], boundary_threshold: int = 0) → torch.Tensor

Parameters

• box_size (height, width) – Size of the reference box covering [0, width] x [0, height]

• boundary_threshold (int) – Boxes that extend beyond the reference box boundary by more than boundary_threshold are considered “outside”.

For RRPN, it might not be necessary to call this function since it’s common for rotated box to extend to outside of the image boundaries (the clip function only clips the near-horizontal boxes)

Returns

a binary vector, indicating whether each box is inside the reference box.

get_centers() → torch.Tensor

Returns

The box centers in a Nx2 array of (x, y).

scale(scale_x: float, scale_y: float) → None

Scale the rotated box with horizontal and vertical scaling factors Note: when scale_factor_x != scale_factor_y, the rotated box does not preserve the rectangular shape when the angle is not a multiple of 90 degrees under resize transformation. Instead, the shape is a parallelogram (that has skew) Here we make an approximation by fitting a rotated rectangle to the parallelogram.

classmethod cat(boxes_list: List[RotatedBoxes]) → cvpods.structures.rotated_boxes.RotatedBoxes

Concatenates a list of RotatedBoxes into a single RotatedBoxes

Parameters

boxes_list (list[RotatedBoxes]) –

Returns

RotatedBoxes – the concatenated RotatedBoxes

property device

__iter__() → Iterator[torch.Tensor]

Yield a box as a Tensor of shape (5,) at a time.

cvpods.structures.pairwise_iou_rotated(boxes1: cvpods.structures.rotated_boxes.RotatedBoxes, boxes2: cvpods.structures.rotated_boxes.RotatedBoxes) → None

Given two lists of rotated boxes of size N and M, compute the IoU (intersection over union) between __all__ N x M pairs of boxes. The box order must be (x_center, y_center, width, height, angle).

Parameters

boxes2 (boxes1,) – two RotatedBoxes. Contains N & M rotated boxes, respectively.

Returns

Tensor – IoU, sized [N,M].