Helper functions for working with bounding boxes (augmentations.bbox_utils)¶
¶
def
albumentations.augmentations.bbox_utils.calculate_bbox_area(bbox, rows, cols)
[view source on GitHub]
¶
Calculate the area of a bounding box in pixels.
Parameters:
| Name | Type | Description |
|---|---|---|
bbox |
tuple |
A bounding box |
rows |
int |
Image height. |
cols |
int |
Image width. |
Returns:
| Type | Description |
|---|---|
int |
Area of a bounding box in pixels. |
def
albumentations.augmentations.bbox_utils.check_bbox(bbox)
[view source on GitHub]
¶
Check if bbox boundaries are in range 0, 1 and minimums are lesser then maximums
def
albumentations.augmentations.bbox_utils.check_bboxes(bboxes)
[view source on GitHub]
¶
Check if bboxes boundaries are in range 0, 1 and minimums are lesser then maximums
def
albumentations.augmentations.bbox_utils.convert_bbox_from_albumentations(bbox, target_format, rows, cols, check_validity=False)
[view source on GitHub]
¶
Convert a bounding box from the format used by albumentations to a format, specified in target_format.
Parameters:
| Name | Type | Description |
|---|---|---|
bbox |
tuple |
An albumentation bounding box |
target_format |
str |
required format of the output bounding box. Should be 'coco', 'pascal_voc' or 'yolo'. |
rows |
int |
Image height. |
cols |
int |
Image width. |
check_validity |
bool |
Check if all boxes are valid boxes. |
Returns:
| Type | Description |
|---|---|
tuple |
A bounding box. |
Note:
The coco format of a bounding box looks like [x_min, y_min, width, height], e.g. [97, 12, 150, 200].
The pascal_voc format of a bounding box looks like [x_min, y_min, x_max, y_max], e.g. [97, 12, 247, 212].
The yolo format of a bounding box looks like [x, y, width, height], e.g. [0.3, 0.1, 0.05, 0.07].
Exceptions:
| Type | Description |
|---|---|
ValueError |
if |
def
albumentations.augmentations.bbox_utils.convert_bbox_to_albumentations(bbox, source_format, rows, cols, check_validity=False)
[view source on GitHub]
¶
Convert a bounding box from a format specified in source_format to the format used by albumentations:
normalized coordinates of bottom-left and top-right corners of the bounding box in a form of
(x_min, y_min, x_max, y_max) e.g. (0.15, 0.27, 0.67, 0.5).
Parameters:
| Name | Type | Description |
|---|---|---|
bbox |
tuple |
A bounding box tuple. |
source_format |
str |
format of the bounding box. Should be 'coco', 'pascal_voc', or 'yolo'. |
check_validity |
bool |
Check if all boxes are valid boxes. |
rows |
int |
Image height. |
cols |
int |
Image width. |
Returns:
| Type | Description |
|---|---|
tuple |
A bounding box |
Note:
The coco format of a bounding box looks like (x_min, y_min, width, height), e.g. (97, 12, 150, 200).
The pascal_voc format of a bounding box looks like (x_min, y_min, x_max, y_max), e.g. (97, 12, 247, 212).
The yolo format of a bounding box looks like (x, y, width, height), e.g. (0.3, 0.1, 0.05, 0.07);
where x, y coordinates of the center of the box, all values normalized to 1 by image height and width.
Exceptions:
| Type | Description |
|---|---|
ValueError |
if |
ValueError |
If in YOLO format all labels not in range (0, 1). |
def
albumentations.augmentations.bbox_utils.convert_bboxes_from_albumentations(bboxes, target_format, rows, cols, check_validity=False)
[view source on GitHub]
¶
Convert a list of bounding boxes from the format used by albumentations to a format, specified
in target_format.
Parameters:
| Name | Type | Description |
|---|---|---|
bboxes |
List[tuple] |
List of albumentation bounding box |
target_format |
str |
required format of the output bounding box. Should be 'coco', 'pascal_voc' or 'yolo'. |
rows |
int |
Image height. |
cols |
int |
Image width. |
check_validity |
bool |
Check if all boxes are valid boxes. |
Returns:
| Type | Description |
|---|---|
list[tuple] |
List of bounding box. |
def
albumentations.augmentations.bbox_utils.convert_bboxes_to_albumentations(bboxes, source_format, rows, cols, check_validity=False)
[view source on GitHub]
¶
Convert a list bounding boxes from a format specified in source_format to the format used by albumentations
def
albumentations.augmentations.bbox_utils.denormalize_bbox(bbox, rows, cols)
[view source on GitHub]
¶
Denormalize coordinates of a bounding box. Multiply x-coordinates by image width and y-coordinates
by image height. This is an inverse operation for :func:~albumentations.augmentations.bbox.normalize_bbox.
Parameters:
| Name | Type | Description |
|---|---|---|
bbox |
tuple |
Normalized bounding box |
rows |
int |
Image height. |
cols |
int |
Image width. |
Returns:
| Type | Description |
|---|---|
tuple |
Denormalized bounding box |
Exceptions:
| Type | Description |
|---|---|
ValueError |
If rows or cols is less or equal zero |
def
albumentations.augmentations.bbox_utils.denormalize_bboxes(bboxes, rows, cols)
[view source on GitHub]
¶
Denormalize a list of bounding boxes.
Parameters:
| Name | Type | Description |
|---|---|---|
bboxes |
List[tuple] |
Normalized bounding boxes |
rows |
int |
Image height. |
cols |
int |
Image width. |
Returns:
| Type | Description |
|---|---|
List[tuple] |
Denormalized bounding boxes |
def
albumentations.augmentations.bbox_utils.filter_bboxes(bboxes, rows, cols, min_area=0.0, min_visibility=0.0)
[view source on GitHub]
¶
Remove bounding boxes that either lie outside of the visible area by more then min_visibility
or whose area in pixels is under the threshold set by min_area. Also it crops boxes to final image size.
Parameters:
| Name | Type | Description |
|---|---|---|
bboxes |
List[tuple] |
List of albumentation bounding box |
rows |
int |
Image height. |
cols |
int |
Image width. |
min_area |
float |
Minimum area of a bounding box. All bounding boxes whose visible area in pixels. is less than this value will be removed. Default: 0.0. |
min_visibility |
float |
Minimum fraction of area for a bounding box to remain this box in list. Default: 0.0. |
Returns:
| Type | Description |
|---|---|
List[tuple] |
List of bounding box. |
def
albumentations.augmentations.bbox_utils.filter_bboxes_by_visibility(original_shape, bboxes, transformed_shape, transformed_bboxes, threshold=0.0, min_area=0.0)
[view source on GitHub]
¶
Filter bounding boxes and return only those boxes whose visibility after transformation is above the threshold and minimal area of bounding box in pixels is more then min_area.
Parameters:
| Name | Type | Description |
|---|---|---|
original_shape |
tuple |
Original image shape |
bboxes |
List[tuple] |
Original bounding boxes |
transformed_shape |
tuple |
Transformed image shape |
transformed_bboxes |
List[tuple] |
Transformed bounding boxes |
threshold |
float |
visibility threshold. Should be a value in the range [0.0, 1.0]. |
min_area |
float |
Minimal area threshold. |
Returns:
| Type | Description |
|---|---|
List[tuple] |
Filtered bounding boxes |
def
albumentations.augmentations.bbox_utils.normalize_bbox(bbox, rows, cols)
[view source on GitHub]
¶
Normalize coordinates of a bounding box. Divide x-coordinates by image width and y-coordinates by image height.
Parameters:
| Name | Type | Description |
|---|---|---|
bbox |
tuple |
Denormalized bounding box |
rows |
int |
Image height. |
cols |
int |
Image width. |
Returns:
| Type | Description |
|---|---|
tuple |
Normalized bounding box |
Exceptions:
| Type | Description |
|---|---|
ValueError |
If rows or cols is less or equal zero |
def
albumentations.augmentations.bbox_utils.normalize_bboxes(bboxes, rows, cols)
[view source on GitHub]
¶
Normalize a list of bounding boxes.
Parameters:
| Name | Type | Description |
|---|---|---|
bboxes |
List[tuple] |
Denormalized bounding boxes |
rows |
int |
Image height. |
cols |
int |
Image width. |
Returns:
| Type | Description |
|---|---|
List[tuple] |
Normalized bounding boxes |
def
albumentations.augmentations.bbox_utils.union_of_bboxes(height, width, bboxes, erosion_rate=0.0)
[view source on GitHub]
¶
Calculate union of bounding boxes.
Parameters:
| Name | Type | Description |
|---|---|---|
height |
float |
Height of image or space. |
width |
float |
Width of image or space. |
bboxes |
List[tuple] |
List like bounding boxes. Format is |
erosion_rate |
float |
How much each bounding box can be shrinked, useful for erosive cropping. Set this in range [0, 1]. 0 will not be erosive at all, 1.0 can make any bbox to lose its volume. |
Returns:
| Type | Description |
|---|---|
tuple |
A bounding box |