streams

A stream serves to identify the origin of a data sequence, commonly referring to a sensor.

The VisionAI schema represents a confluence of multi-sensor (stream) information, allocated within a specific space, that enables the description of corresponding annotation streams. A stream key contains a wealth of sensor information, such as intrinsic calibration parameters for cameras.

Hint

When your data includes only one sensor (e.g., camera), it is sufficient to provide the description of your stream (sensor name and type) without the need for additional calibration information.

For example:

"streams": { "camera1": { "type": "camera" } }

Example

"streams": {
    "camera1": {
        "type": "camera",
        "uri": "./some_path/some_video.mp4",
        "description": "Frontal camera",
        "stream_properties": { 
            "intrinsics_pinhole": {
                "camera_matrix_3x4": [ 1000.0,    0.0, 500.0, 0.0,
                                            0.0, 1000.0, 500.0, 0.0,
                                            0.0,    0.0,   1.0, 0.0],
                "height_px": 480,
                "width_px": 640
            }
        }
    }
}

streams {}

name	description	type	required
${STREAM_NAME}	The name of this stream	object	true
type	The type of this string. Must be one of "camera", "lidar".	string	true
uri	The uri of file of this stream. Setting uri here means this sequence has only this stream file. (static information)	string	false
description	The description of the stream.	string	false
stream_properties	The object in stream properties must be one of the following types. All types are an object. ➤ intrinsics_pinhole The object details follow the intrinsics as below table.	object	by project setting

Intrinsics {}

The intrinsic parameters of a camera pertain to how the device captures images. These parameters include factors like focal length, aperture, field-of-view, resolution, and others that influence the intrinsic matrix of a camera model.

The intrinsic matrix denotes a transformation matrix that converts points from the camera's coordinate system into the pixel coordinate system.

Intrinsic information in the VisionAI format serves solely as a means of recording relevant data and is not utilized in any system-based conversion processes.

intrinsics_pinhole # recording relevant data

name	type	required
camera_matrix_3x4	12 elements array of float	true
distortion_coeffs_1xN	number of array	false
height_px	int	true
width_px	int	true

Project Sensor Settings

The inclusion of “stream_properties” in the “streams“ is contingent on the sensor settings of each project. Please consult the following combination for more information:

Project Sensor Settings	stream_properties (required)
1* camera	false
n* cameras	false
1* lidar	false
n* lidars	false
m* camera + n* lidar	true

---

Use Case

bbox

To describe a bbox dataset with one camera sensor:

• sensor: camera (#camera1)

Example Code

pagebbox

bbox + cuboid (3d)

To describe a dataset with one camera sensor (bbox annotation) and one lidar sensor (cuboid annotation) in the coordinate system of iso8855-1:

• sensor: camera (#camera1), lidar (#lidar1)

Example Code

pagebbox + cuboid (3d)