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Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment

1    Definition

Visual Scene Descriptors are a Data Type including the Visual Objects of a scene, their Sub-Scenes, and their arrangement in the Scene. Visual Scene Descriptors may be hierarchical, i.e., they may contain Objects and Visual Scene Descriptors.

2    Functional Requirements

A Visual Scene Descriptors instance must include:

  1. The Visual Scene Descriptors Header.
  2. The ID of the Visual Scene Descriptors instance.
  3. The ID of the Visual Objects in the Visual Scene.
  4. The ID of the Visual Sub-Scenes in the Visual Scene.
  5. The Space-Time information of the Visual Objects and Visual Sub-Scenes in the Visual Scene.

A Visual Scene Descriptors instance may include:

  1. The ID of a virtual Space (M-Instance) where it is or it is intended to be located.
  2. The ID of a U-Environment where it is or it is intended to be located.
  3. The Space-Time information of the Visual Scene.
  4. The Point of View of the Viewer.
  5. Information about this Visual Scene Descriptors instance.
  6. Descriptive Metadata.

3    Syntax

https://schemas.mpai.community/OSD/V1.5/data/VisualSceneDescriptors.json

4    Semantics

Table 1 – Semantics of the Visual Scene Descriptors Data Type

Label Description
Header Visual Scene Descriptors Header – Standard “OSD-VSD-Vx.y”.
MInstanceID Identifier of the M-Instance.
UEnvironmentID Identifier of the U-Environment.
VisualDescriptorsID ID of this Visual Scene Descriptors instance.
VisualDescriptorsSpaceTime Space and Time of this Visual Scene Descriptors instance.
ViewerPointOfView Point of View of the Viewer.
ObjectCount Number of Visual Objects in Visual Scene.
Objects[] Set of Data related to Visual Objects in the Visual Scene.
– ObjectSpaceTime Space and Time of Visual Object in the Visual Scene.
– ObjectIDOrObject Visual Object in the Scene.
SubVisualCount Number of Visual Sub-Scenes in Visual Scene.
SubVisuals[] Set of Data related to Visual Sub-Scenes in the Scene.
– SubVisualSpaceTime Space and Time of Visual Sub-Scene in the Scene.
– SubVisualIDOrSubVisual A Visual Sub-Scene in the Scene.
DataXMData MPAI-PTF Data Exchange Metadata providing provenance, authorisation, legal, security, and confidence information associated with this Visual Scene Descriptors instance in a trusted data exchange context.
DescrMetadata Human-readable descriptive metadata of the Visual Scene Descriptors instance (plain text, max 2048 characters).

5    Conformance Testing

A Data instance conforms with Visual Scene Descriptors (OSD-VSD) if:

  1. The Data validates against the Visual Scene Descriptors JSON Schema.
  2. All Data in the Visual Scene Descriptors JSON Schema:
    1. Have the specified type.
    2. Validate against their JSON Schemas.
    3. Conform with their Data Qualifiers.

6    Performance Assessment

Not part of this specification.

Go to MPAI-OSD V1.5 Data Types