Sample formats
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A is a data point you want to label. Samples come in different types, like an image, a 3D point cloud, or a video sequence. When uploading () or downloading () a sample using the , the format of the attributes
field depends on the type of sample. The different formats are described here.
Supported image formats: jpeg, png, bmp.
If the image file is on your local computer, you should first upload it to our asset storage service (using ) or to another cloud storage service.
Supported image formats: jpeg, png, bmp.
pcd
Required. Point cloud data.
images
Reference camera images.
name
string
Name of the sample.
timestamp
int
, float
, or string
Timestamp of the sample. Should be in nanoseconds for accurate velocity/acceleration calculations. Will also be used for interpolation unless disabled in dataset settings.
ego_pose
Pose of the sensor that captured the point cloud data.
default_z
float
Default z-value of the ground plane. 0 by default. Only valid in the point cloud cuboid editor. New cuboids will be drawn on top of the ground plane, i.e. the default z-position of a new cuboid is 0.5 (since the default height of a new cuboid is 1).
bounds
dict
of <string
, float
>
Point cloud bounds: a dict
with values that are used to initialize the limiting cuboid. The z-values are also used for height coloring when provided.
Supported values: min_x
, max_x
, min_y
, max_y
, min_z
and max_z
.
url
string
Required. URL of the point cloud data.
type
string
: "pcd" | "binary-xyzi" | "kitti" | "binary-xyzir" | "nuscenes" | "ply"
A calibrated or uncalibrated reference image corresponding to a point cloud. The reference images can be opened in a new tab from within the labeling interface. You can determine the layout of the images by setting the row
and col
attributes on each image. If you also supply the calibration parameters (and distortion parameters if necessary), the main point cloud view can be set to the image to obtain a fused view.
name
string
Name of the camera image.
url
string
Required. URL of the camera image.
row
int
Required. Row of this image in the images viewer.
col
int
Required. Column of this image in the images viewer.
intrinsics
Intrinsic parameters of the camera.
extrinsics
distortion
Distortion parameters of the camera.
camera_convention
string
: "OpenGL" | "OpenCV"
Convention of the camera coordinates. We use the OpenGL/Blender coordinate convention for cameras. +X is right, +Y is up, and +Z is pointing back and away from the camera. -Z is the look-at direction. Other codebases may use the OpenCV convention, where the Y and Z axes are flipped but the +X axis remains the same. See diagram 1.
rotation
float
intrinsic_matrix
translation
object
: {
"x": float
,
"y": float
,
"z": float
}
rotation
object
: {
"qx": float
,
"qy": float
,
"qz": float
,
"qw": float
}
model
string
: "fisheye" | "brown-conrady"
coefficients
Fisheye:
object
: {
"k1": float
,
"k2": float
,
"k3": float
,
"k4": float
,
}
Brown-Conrady:
object
: {
"k1": float
,
"k2": float
,
"k3": float
,
"p1": float
,
"p2": float
}
The pose of the sensor used to capture the 3D point cloud data. This can be helpful if you want to obtain cuboids in world coordinates, or when your sensor is moving. In the latter situation, supplying an ego pose with each frame will ensure that static objects do not move when switching between frames.
position
object
: {
"x": float
,
"y": float
,
"z": float
}
Required. XYZ position of the sensor in world coordinates.
heading
object
: {
"qx": float
,
"qy": float
,
"qz": float
,
"qw": float
}
Segments.ai uses 32-bit floats for the point positions. Keep in mind that 32-bit floats have limited precision. In fact, only 24 bits can be used to represent the number itself (the significand, excluding the sign bit), or about 7.22 decimal digits. If you want to keep two decimal places, this only leaves 5.22 decimal digits, so the numbers shouldn't be larger than 10^5.22 = 165958.
To avoid rounding problems, it is best practice to subtract the ego position of the first frame from all other ego positions. This way, the first ego position is set to (0, 0, 0) and the subsequent ego positions are relative to (0, 0, 0) . In your export script, you can add the ego position of the first frame back to the object positions.
frames
Required. List of 3D point cloud frames in the sequence.
sensors
Required. List of the sensors that can be labeled.
name
string
Required. The name of the sensor.
task_type
string
attributes
object
array
of
See for the supported file formats.
Required. Type of the point cloud data. See file formats for the list of supported file formats.
If the point cloud file is on your local computer, you should first upload it to our asset storage service (using ) or to another cloud storage service.
Extrinsic parameters of the camera relative to the .
The rotation that needs to be applied when displaying the image. Valid options are 0, , , and . Useful for when a camera is mounted upside-down.
If the image file is on your local computer, you should first upload it to our asset storage service (using ) or to another cloud storage service.
2D array
of float
s representing 3x3 matrix in row-major order
Required. Intrinsic matrix used in the pinhole camera model.
and are the focal lengths in pixels. We assume square pixels, so . and are the offsets (in pixels) of the principal point from the top-left corner of the image frame.
Required. Translation of the camera in lidar coordinates, i.e., relative to the .
Required. Rotation of the camera in lidar coordinates, i.e., relative to the (or equivalently: a transformation from camera frame to ego frame). Defined as a . By default, we use the OpenGL/Blender coordinate convention for cameras. +X is right, +Y is up, and +Z is pointing back and away from the camera. -Z is the look-at direction. Other codebases may use the OpenCV convention, where the Y and Z axes are flipped but the +X axis remains the same. See diagram 1. You can specify the camera convention in .
Required. Type of the distortion model: or .
Required. Coefficients of the distortion model: k1
, k2
, k3
, k4
for fisheye (see the ) and k1
, k2
, k3
, p1
, p2
for Brown-Conrady (see the , note that and are not used).
Required. Orientation of the sensor. Defined as a .
array
of
array
of
Required. The of the sensor. Currently, pointcloud-cuboid-sequence
and image-vector-sequence
are supported.
Required. The sample attributes for the sensor. Currently, and are supported.