Objects

Supported Shapes

Supervisely Annotation Format supports the following figures:

  • point

  • rectangle

  • polygon

  • line / polyline

  • bitmap

  • keypoint structures

  • cuboid

Coordinate System

For two-dimensional mediums (images and videos) we use the following coordinate system (it's similar to a two-dimensional NumPy coordinate system):

coordinate system

All numberical values are provided in pixels.

General Fields

When generating JSON annotation files, we assign each figure a mix of general fields and fileds unique for each geometric shape. Some of the general fields are optional: the system generates them automatically when the data is uploaded/first created. This means that these fields can be omitted during manual annotation.

Optional fields:

"id": 503051990,
"classId": 1693352,
"labelerLogin": "alexxx",
"createdAt": "2020-08-22T09:32:48.010Z",
"updatedAt": "2020-08-22T09:33:08.926Z".

Fields definitions:

  • id - unique identifier of the current object

  • classId - unique class identifier of the current object

  • labelerLogin - string - the name of user who created the current figure

  • createdAt - string - date and time of figure creation

  • updatedAt - string - date and time of the last figure update

Point

Example:

point example

Json format for this shape:

{
"id": 503051990,
"classId": 1693352,
"labelerLogin": "alexxx",
"createdAt": "2020-08-22T09:32:48.010Z",
"updatedAt": "2020-08-22T09:33:08.926Z",
"description": "",
"geometryType": "point",
"tags": [],
"classTitle": "point",
"points": {
"exterior": [
[
1334,
907
]
],
"interior": []
}
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "point" - class shape

  • tags - list of tags assigned to the current object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • points - object with two fields:

    • exterior - list of 2 values for coordinates (x and y in that order) for every figure

    • interior - always an empty field for this type of figure

Rectangle

Example:

rectangle example

Json format for this figure:

{
"id": 283051572,
"classId": 1692857,
"labelerLogin": "max",
"createdAt": "2020-08-22T09:32:48.010Z",
"updatedAt": "2020-08-22T09:33:08.926Z",
"description": "",
"geometryType": "rectangle",
"tags": [],
"classTitle": "person_bbox",
"points": {
"exterior": [
[
533,
63
],
[
800,
830
]
],
"interior": []
}
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "rectangle" - class shape

  • tags - list of tags assigned to the current object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • points - object with two fields:

  • exterior - list of two lists, each containing two coordinates (x and y in that order), with the following structure: [[left, top], [right, bottom]]

  • interior - always an empty list for this type of figure

Polygon (without holes)

Example:

polygon example
{
"id": 503004154,
"classId": 1693021,
"labelerLogin": "alexxx",
"createdAt": "2020-08-21T15:15:28.092Z",
"updatedAt": "2020-08-21T15:15:37.687Z",
"description": "",
"geometryType": "polygon",
"tags": [],
"classTitle": "triangle",
"points": {
"exterior": [
[
730,
2104
],
[
2479,
402
],
[
3746,
1646
]
],
"interior": []
}
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "polygon" - class shape

  • tags - list of tags assigned to the curent object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • points - object with two fields:

  • exterior - list of points [point1, point2, point3, etc ...] where each point is a list of two numbers (coordinates) [col, row]

  • interior - list of elements with the same structure as the "exterior" field. In other words, this is the list of polygons that define object holes. For polygons without holes in them, this field is empty

Polygon (without holes)

Example:

polygon example
{
"id": 503004154,
"classId": 1693021,
"labelerLogin": "alexxx",
"createdAt": "2020-08-21T15:15:28.092Z",
"updatedAt": "2020-08-21T16:06:11.461Z",
"description": "",
"geometryType": "polygon",
"tags": [],
"classTitle": "triangle_hole",
"points": {
"exterior": [
[
730,
2104
],
[
2479,
402
],
[
3746,
1646
]
],
"interior": [
[
[
1907,
1255
],
[
2468,
875
],
[
2679,
1577
]
]
]
}
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "polygon" - class shape

  • tags - list of tags assigned to the curent object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • points - object with two fields:

  • exterior - list of points [point1, point2, point3, etc ...] where each point is a list of two numbers (coordinates) [col, row]

  • interior - list of elements with the same structure as the "exterior" field. In other words, this is the list of polygons that define object holes.

Polyline

Example:

polyline example
{
"id": 503049791,
"classId": 1693340,
"labelerLogin": "alexxx",
"createdAt": "2020-08-22T08:39:29.386Z",
"updatedAt": "2020-08-22T08:39:34.802Z",
"description": "",
"geometryType": "line",
"tags": [],
"classTitle": "line",
"points": {
"exterior": [
[
211,
2266
],
[
1208,
1310
],
[
369,
981
]
],
"interior": []
}
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "line" - class shape

  • tags - list of tags assigned to the current object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • points - object with two fields:

  • exterior - list of points [point1, point2, point3, etc ...] where each point is a list of two numbers (coordinates) [col, row]

  • interior - always an empty list for this type of figure

Bitmap

Bitmap is a figure that is described by a point of "origin"(upper left corner), which defines the location of the bitmap within the image and a "data" - Boolean matrix encoded into a string, which defines each pixel of the bitmap.

Example:

bitmap example
{
"id": 497489556,
"classId": 1661459,
"labelerLogin": "alexxx",
"createdAt": "2020-07-24T07:30:39.202Z",
"updatedAt": "2020-07-24T07:41:12.753Z",
"description": "",
"geometryType": "bitmap",
"tags": [],
"classTitle": "person",
"bitmap": {
"data": "eJwB ... kUnW",
"origin": [
535,
66
]
}
}

Fields description:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "bitmap" - class shape

  • tags - list of tags assigned to the current object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • bitmap - object with two fields:

    • origin - points (x and y coordinates) of the top left corner of the bitmap, i.e. the position of the bitmap within the image

    • data - string - encoded representation of a string

A few words about bitmap -> data. You can use these two python methods to convert a base64 encoded string to numpy and vice versa.

def base64_2_mask(s):
z = zlib.decompress(base64.b64decode(s))
n = np.fromstring(z, np.uint8)
mask = cv2.imdecode(n, cv2.IMREAD_UNCHANGED)[:, :, 3].astype(bool)
return mask
def mask_2_base64(mask):
img_pil = Image.fromarray(np.array(mask, dtype=np.uint8))
img_pil.putpalette([0,0,0,255,255,255])
bytes_io = io.BytesIO()
img_pil.save(bytes_io, format='PNG', transparency=0, optimize=0)
bytes = bytes_io.getvalue()
return base64.b64encode(zlib.compress(bytes)).decode('utf-8')

Example:

import numpy as np
import cv2, zlib, base64, io
from PIL import Image
def base64_2_mask(s):
z = zlib.decompress(base64.b64decode(s))
n = np.fromstring(z, np.uint8)
mask = cv2.imdecode(n, cv2.IMREAD_UNCHANGED)[:, :, 3].astype(bool)
return mask
def mask_2_base64(mask):
img_pil = Image.fromarray(np.array(mask, dtype=np.uint8))
img_pil.putpalette([0,0,0,255,255,255])
bytes_io = io.BytesIO()
img_pil.save(bytes_io, format='PNG', transparency=0, optimize=0)
bytes = bytes_io.getvalue()
return base64.b64encode(zlib.compress(bytes)).decode('utf-8')
example_np_bool = np.ones((3, 3), dtype=bool)
example_np_bool[1][1] = False
example_np_bool[1][2] = False
print(example_np_bool)
encoded_string = mask_2_base64(example_np_bool)
print(encoded_string)
print(base64_2_mask(encoded_string))

Program output after executing the code:

[[ True True True]
[ True False False]
[ True True True]]
'eJzrDPBz5+WS4mJgYOD19HAJAtLMIMwIInOeqf8BUmwBPiGuQPr///9Lb86/C2QxlgT5BTM4PLuRBuTwebo4hlTMSa44cOHAB6DqY0yORgq8YkAZBk9XP5d1TglNANAFGzA='
[[ True True True]
[ True False False]
[ True True True]]

Keypoint structure

Keypoint structures consist of vertices (also called nodes or points) which are connected by edges (also called links or lines).

Example:

key_point_structurebitmap example
{
"id": 503055304,
"classId": 1693357,
"description": "",
"geometryType": "graph",
"labelerLogin": "alexxx",
"createdAt": "2020-08-22T10:50:28.336Z",
"updatedAt": "2020-08-22T10:53:57.760Z",
"tags": [],
"classTitle": "graph",
"nodes": {
"8e20c830-ee86-450f-9d21-833eec53e3c5": {
"loc": [
1017,
1556
]
},
"bf89e248-7b3b-4732-888a-99d3369fbb2f": {
"loc": [
1024,
394
]
},
"66502c5b-8d98-492c-bb48-8ce7c4487038": {
"loc": [
1026,
738
]
},
"56517c2a-6053-442a-9af2-bd6f29bae987": {
"loc": [
668,
574
]
},
"7a40d5f7-bcc8-4e2f-bf3b-3e52d39c4206": {
"loc": [
1388,
549
]
}
}
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "graph" - class shape

  • tags - list of tags assigned to the current object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • nodes - is a dictionary, where keys denote the names of the graph vertices and values in a dictionary, and where values denote location of a node on image

    • loc - list of single points (x and y coordinates) of a vertice

Cuboids (2D annotation)

Example:

cuboid 2d example
{
"description": "",
"tags": [],
"classTitle": "Cuboid",
"faces": [
[
0,
1,
2,
3
],
[
0,
4,
5,
1
],
[
1,
5,
6,
2
]
],
"points": [
[
277,
273
],
[
840,
273
],
[
840,
690
],
[
277,
690
],
[
688,
168
],
[
1200,
168
],
[
1200,
522
]
]
}

Fields definitions:

  • Optional fields id, classId, labelerLogin, createdAt, updatedAt are described above

  • description - string - text description (optional)

  • geometryType: "graph" - class shape

  • tags - list of tags assigned to the current object

  • classTitle - string - the title of the current class. It's used to identify the corresponding class shape from the meta.json file

  • points - an array of points that form the cuboid. There are always 7 points in a cuboid. Each Point is presented as an array of X and Y coordinates, i.e. [277, 690] means X is 277 and Y is 690, calculating from the top left corner of the image.

  • faces - an array of faces that indicates how points from the points array are connected. There are always 3 faces in a cuboid. In the example above, you can see that face number 3 that consists of points 1, 2, 5, 6 with coordinates [840, 273], [840, 690], [1200, 168], [1200, 522]. Check the image below: