1     Definition

The Visual Qualifier is a set of Data providing additional information on Visual Data for potential use by a machine.

The combination of Visual Data and Visual Qualifier is called Visual Object and is specified by
MPAI-OSD V1.5.

2     Functional Requirements

The Visual Qualifier allows the expression of the following Elements:

Users needing additional entries in the Visual Qualifier or support of new Qualifiers should make a documented request to the MPAI Secretariat.
Requests will be considered by the appropriate MPAI committee.

3     Syntax


https://schemas.mpai.community/TFA/V1.5/data/VisualQualifier.json

4     Semantics

4.1  Sub-Types

Defines visual signal characteristics.

  • ColourFormat: colour representation (see
    ColourFormats)
  • AlphaChannel: transparency level
  • Brightness: intensity measure
  • ColourSubsampling: chroma sampling (4:4:4, 4:2:2, 4:2:0, 4:1:1)
  • YUV / CMYK: colour encoding systems

4.2  Formats

4.2.1  Content

Defines the structure of visual data.

  • TimeSampling:
    • Precision (bits per pixel)
    • Time sampling
    • Spatial sampling
  • 2D Content:
    • Static: no temporal evolution
    • Dynamic: includes temporal variation
  • 3D Content:
    • Static: single spatial representation
    • Dynamic: temporal evolution of spatial data

4.2.2  Transport

Defines how Visual Data is transported.

  • FileFormat (e.g. image/video container formats)
  • StreamFormat (streaming protocols)

4.3  Attributes

4.3.1  Source

Defines the origin of the Visual Data.

  • Real: acquired from physical devices (e.g. cameras)
  • Synthetic:
    • Raster
    • Vector

4.3.2  Device

Defines the device used for capturing or rendering visual data.

  • DeviceRole:
    • Capture (e.g. camera, depth camera)
    • Render (e.g. display, HMD)
    • Bidirectional
  • DeviceType:
    • Camera
    • DepthCamera
    • Display
    • HMD
    • WearableCamera
  • Optics:
    • FieldOfView
    • FocalLength
    • Aperture
  • CaptureConfiguration:
    • Resolution
    • FrameRate
    • SamplingMode (Progressive, Interlaced)
  • RenderConfiguration:
    • Resolution
    • DisplayType (LCD, OLED, etc.)
    • RefreshRate
  • OperationalParameters:
    • Brightness
    • Contrast
    • DynamicRange

4.3.3  Metadata

Additional metadata describing the visual content.

  • VisualMetadataFormats (see schema reference)
  • ObjectID
  • EntityInternalStatus

4.4  Conceptual Model

The Visual Qualifier describes:

  • The structure of the data (Formats)
  • The nature of the signal (SubTypes)
  • The origin (Source)
  • The system interacting with the signal (Device)

 

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