pivmeta
type: Ontology
version IRI: https://matthiasprobst.github.io/pivmeta/1.0.0
abstract: This is an ontology draft for the description of Particle Image Velocimetry data. It is currently limited to planar PIV (2D2C and 2D3C) setups.
created: 2024-01-03
creator: Matthias Probst (https://orcid.org/0000-0001-8729-0482), Institut für Thermische Strömungsmaschinen
license: https://creativecommons.org/licenses/by/4.0/
modified: 2024-01-03
title: pivmeta: An ontology draft for describing particle image velocimetry data.
preferred namespace prefix: pivmeta
contact person: https://orcid.org/0000-0001-8729-0482
version info: v1.0.0

part of
type: ObjectProperty
type: TransitiveProperty
definition: a core relation that holds between a part and its whole

has part
type: ObjectProperty
type: TransitiveProperty
definition: a core relation that holds between a whole and its part

precedes
type: ObjectProperty
type: TransitiveProperty
domain: Process
range: Process
definition: x precedes y if and only if the time point at which x ends is before or equivalent to the time point at which y starts. Formally: x precedes y iff ω(x) <= α(y), where α is a function that maps a process to a start point, and ω is a function that maps a process to an end point.

immediately precedes
type: ObjectProperty
sub property of: precedes
domain: Process
range: Process
definition: X immediately precedes_Y iff: end(X) simultaneous_with start(Y)

has employed tool
type: ObjectProperty
sub property of: uses instrument
inverse of: is employed tool
domain: ProcessingStep
range: Tool
definition: Points to a tool that is used within a given processing step

has parameter
type: ObjectProperty
domain: Class
  union of: Method
  union of: Tool
  union of: Virtual Tool
range: Variable
definition: Points to a parameter of a given method or tool.

is employed tool
type: ObjectProperty
definition: Points to a processing step the tool has been used in

distribution
type: ObjectProperty
domain: Dataset
range: Distribution
definition: An available distribution of the dataset.

has source code
type: ObjectProperty
inverse of: is source code of
domain: Class
  union of: Virtual PIV Setup
  union of: Virtual Tool
range: software source code
definition: Relates a computational model or concept to the source code that implements it.

is source code of
type: ObjectProperty
domain: software source code
range: Class
  union of: Virtual PIV Setup
  union of: Virtual Tool

flag
type: ObjectProperty
inverse of: flag in
domain: Class
  union of: HDF5 Dataset
  union of: Flag Statistics
range: Flag Variable
definition: Relates something to a Flag Variable

flag in
type: ObjectProperty
definition: Relates a Flag Variable to its used concept

has standard name
type: ObjectProperty
domain: NumericalVariable
range: StandardName

manufacturer
type: ObjectProperty
domain: Tool
range: Organization
definition: Manufacturer of a m4i:Tool

outlier replacement scheme
type: ObjectProperty
domain: PIV Validation
range: Outlier Replacement Scheme
definition: Points to the outlier replacement scheme used by the PIV validation process.

piv image type
type: ObjectProperty
domain: PIV Image Distribution
range: DCMI Type
definition: The type of image, e.g. an experimental or synthetic one. Helps to identify the image source and hence assists processing or analysing PIV data.
example: Individuals of type ImageType are provided by the ontology, e.g. pivmeta:ExperimentalImage

window weighting function
type: ObjectProperty
domain: Correlation Method
range: Window Weighting Function
definition: Points to the window weighting function used by the correlation method.

unit
type: ObjectProperty
domain: StandardName
range: Unit
definition: The canonical unit of the standard name

uses instrument
type: ObjectProperty
domain: Activity
definition: points to an object that helped the agent perform the action (e.g., John wrote a book with a pen)

has value
type: DatatypeProperty
domain: Variable
definition: A value of any type

filename pattern
type: DatatypeProperty
domain: PIV Distribution
range: string
definition: The regular expression string to determine the image filenames in the distribution.

fnumber
type: DatatypeProperty
domain: Camera
range: Literal

has flag meaning
type: DatatypeProperty
domain: Flag Variable
range: string
definition: The flag meanings data property provides the string representations of the pvmeta:flagValues data property.
example: For pivmeta:flagValues=[0, 1, 2, 4, 8, 16, 32, 64, 128], the meaning could be: pivmeta:flagMeanings=["inactive", "active", "masked", "noresult", "disabled", "filtered", "interpolated", "replaced", "manualedit"]

has flag value
type: DatatypeProperty
sub property of: hasNumericalValue
domain: Flag Variable
range: int
definition: The data property flag values provides binary flag values which are explained by pivmeta:flagValues. From the flag values, new flags can be computed by bitwise OR operation, e.g. 1 | 16=17.
example: pivmeta:flagValues=[0, 1, 2, 4, 8, 16, 32, 64, 128]. The corresponding meaning would be: pivmeta:flagMeanings=["inactive", "active", "masked", "noresult", "disabled", "filtered", "interpolated", "replaced", "manualedit"] A flag value of 17 means "active and filtered", which is obtained by bitwise AND operation. A JSON-LD excerpt could look like this: { "@type": "m4i:NumericalVariable", "pivmeta:flagValues": [0, 1, 2, 4, 8, 16, 32, 64, 128], "pivmeta:flagMeanings": [ "inactive", "active", "masked", "noresult", "disabled", "filtered", "interpolated", "replaced", "manualedit" ], "units": "http://qudt.org/vocab/unit/M-PER-SEC" }

bit depth
type: DatatypeProperty
domain: PIV Image Distribution
range: positiveInteger
definition: The bit depth of an image

number of records
type: DatatypeProperty
domain: PIV Image Distribution
range: positiveInteger
definition: The number of records. A record describes the number of images needed for the evaluation of a single PIV velocity field. E.g. a double image recording stored in two separate files A1.tiff and B1.tiff counts as one record. Hence, the number of records correspond to the number of velocity fields, if all records are taken into account in the evluation process.

time format
type: DatatypeProperty
domain: Temporal Variable
range: string
definition: Defines the format string used to decode a date time format.
example: YYYY-MM-DDTHH:MM:SS.ffffff

standard name
type: DatatypeProperty
domain: StandardName
range: string
definition: Name for a standard name, e.g. "x_velocity". The construction of a standard name string is defined by the standard name table. E.g. no spaces are allowed and specific pre- and suffixes are allowed.
example: x_derivative_of_y_velocity

with image deformation
type: DatatypeProperty
domain: Multipass
range: boolean
definition: Flag, indicating whether the algorithm uses image deformation technique as described in Raffel et al. (2018) "Particle Image Velocimetry: A Practical Guide", Springer, https://doi.org/10.1007/978-3-319-68852-7.

has documentation
type: DatatypeProperty
domain: Software
range: anyURI

Experiment
type: Class
definition: An experiment is a process that is intended to replicate a physical phenomenon in a controlled environment.

Physics Based Simulation
type: Class
definition: A simulation that relies on physics based models, according to the Review of Materials Modelling and CWA 17284:2018.

HDF5 Dataset
type: Class
definition: An HDF5 Dataset.

realizable entity
type: Class
definition: To say that b is a realizable entity is to say that b is a specifically dependent continuant that inheres in some independent continuant which is not a spatial region and is of a type instances of which are realized in processes of a correlated type. (axiom label in BFO2 Reference: [058-002])
preferred label: realisierbare Entität @de

DCMI Type
type: Class
definition: The set of classes specified by the DCMI Type Vocabulary, used to categorize the nature or genre of the resource.

Unit
type: Class
definition: Unit of measure

Method
type: Class
subclass of: realizable entity
definition: Abstract description of a method for analysis, generation and transformation of data and material objects like, e.g., 'Fourier Transform Infrared Spectroscopy' or 'Molecular Dynamics Simulation'. Note that while values for relevant parameters should be provided, m4i:Method does not refer to the actual execution of the process that is described (use m4i:ProcessingStep for that), but rather a description of the underlying principle.

Text Variable
type: Class
subclass of: Variable

Tool
type: Class
definition: Object that helps an agent perform an action (e.g., John wrote a book with a pen), i.e., an object of the relation schema:instrument or m4i:hasTool

Property
type: Class
subclass of: Variable
definition: Property, i.e., a variable that can be considered (as an investigated property, i.e., target property) within a processing step

Variable
type: Class
subclass of: Intangible
definition: Variable, i.e., a conventional that is employed for something to which values can be assigned (this may include different notations for the same variable including, e.g., computational representations); this is to be understood very generally, e.g., a variable may be an array or set of elements or have another kind of internal structure

Dataset
type: Class

Activity
type: Class
subclass of: Process

Background Image Generation
type: Class
subclass of: Piv Pre processing
definition: The process of creating or recording background images

Background Subtraction
type: Class
subclass of: Piv Pre processing
example: Can be direct subtraction of background, division of image by background or a combination.

Camera
type: Class
subclass of: Optic Sensor
comment: Use 'has part' to relate components like an objective to the camera

Correlation Method
type: Class
subclass of: Method
definition: The correlation method used by the PIV evaluation process

Digital Camera
type: Class
subclass of: Camera
definition: A Digital Camera captures photographs or videos in a digital format.

Experimental PIV Setup
type: Class
subclass of: PIV Setup
comment: Use prov:hasPart to relate the tools used.
definition: An experimental setup applying the Particle Image Velocimetry method. The class should be related to the tools used in the experiment.

Flag Statistics
type: Class
subclass of: NumericalVariable
definition: Holds statistics, e.g. the number of data points associated with a Flag Variable.

Flag Variable
type: Class
subclass of: NumericalVariable
comment: A flag indicates the processing status of a vector. It can be disabled, active or processed in any other way by a post-processing step. The flag meaning must be provided with the dataset through flag meanings and flag values. Recommendation for the flag meaning are 0-inactive, 1-active, 2-masked, 4-no result, 8-disabled, 16-filtered, 32-interpolated, 64-replaced, 128-manualedit. Combinations of the flags can be used by bitwise OR operation. For example, 33 would mean that the vector is active and interpolated. Provide pivmeta:flagMeaning und pivmeta:flagValues with it.
definition: A variable that expects flag values as integer values.

Image Dewarping
type: Class
subclass of: Piv Pre processing
definition: The process of dewarping an distorted image, e.g. due to the fisheye effect.

Image Filtering
type: Class
subclass of: Piv Pre processing
definition: A process of manipulate an image in order to remove unwanted effects or enahnce certain information in an image.

Image Manipulation Method
type: Class
subclass of: Method
definition: The image manipulation method used by the PIV pre-processing step, e.g. image rotation.

Image Rotation
type: Class
subclass of: Piv Pre processing
comment: If not further specified assume anti-clockwise.
definition: The process of rotating an Image

Interrogation Method
type: Class
subclass of: Method

Laser
type: Class
equivalent class: Q38867
subclass of: Light Source
definition: A Device which emits light via amplification.

Lens
type: Class
subclass of: Optical Component

Lens System
type: Class
subclass of: Optical Component
definition: A number of lenses used in combination.

Light Source
type: Class
equivalent class: Q1146001
subclass of: Optical Component
definition: An object or device that emits light

Mask Generation
type: Class
subclass of: Piv Pre processing
definition: The process of creating a mask to disabled parts in an image.

Multigrid
type: Class
subclass of: Interrogation Method
definition: PIV multi grid method. The correlation and validation methods are executed on different interrogation window sizes starting from large to small.

Multipass
type: Class
subclass of: Interrogation Method
definition: A PIV multiple pass interrogation window, which uses the local integer displacement in a subsequent interrogation pas by offsetting the the interrogation windows. This increases the singal-to-noise ratio of the coorelation peak as unmatched particle images are avoided.

Objective
type: Class
subclass of: Tool
subclass of: Lens System
definition: The optical element that gathers light and focuses it on the camera sensor.

Optic Sensor
type: Class
subclass of: Optical Component

Optical Component
type: Class
subclass of: Tool

Outlier Detection Method
type: Class
subclass of: Method
definition: Outlier detection method used to mark or interpolate spurious vectors.

Outlier Replacement Scheme
type: Class
subclass of: Concept
definition: Method used, to replace outliers.

PIV Dataset
type: Class
subclass of: Dataset
subclass of: Class
  union of: Restriction
    some values from: PIV Setup
    on property: has part
  union of: Restriction
    some values from: PIV Image Distribution
    on property: distribution
  union of: Restriction
    some values from: PIV Mask Distribution
    on property: distribution
  union of: Restriction
    some values from: PIV Result Distribution
    on property: distribution
comment: Use obo:hasPart to relate a used Tool like a camera or laser to the PIV Dataset
definition: A collection of Particle Image Velocimetry (PIV) data, published or curated by a single agent, and available for access or download in one or more representations.

PIV Distribution
type: Class
subclass of: Distribution
definition: A PIV-specific distribution. Subclasses of it are image mask and result distribution which should be used rather than this class. The subclasses describe more clearly the distribution content.

PIV Evaluation
type: Class
subclass of: PIV Processing Step
subclass of: Restriction
  some values from: PIV Post Processing
  on property: precedes
definition: The PIV evaluation processing performing the correlation algorithm and interrogation method.

PIV Image Distribution
type: Class
subclass of: PIV Distribution
definition: A PIV image, which has been recorded by a camera or created synthetically. To distinguish between physical and synthetical images, use the object property "piv image type".

PIV Mask Distribution
type: Class
subclass of: PIV Distribution

PIV Particle
type: Class
subclass of: Tool
definition: Refers to one or generally many tracer particles, also called seeding particles. Its parameters should be described via m4i:hasParameter.

PIV Post Processing
type: Class
subclass of: PIV Processing Step
definition: The process after the main evaluation. Used to remove or mark outliers (invalid data) in the PIV solution

Piv Pre processing
type: Class
subclass of: PIV Processing Step
subclass of: Restriction
  some values from: PIV Evaluation
  on property: precedes

PIV Processing Step
type: Class
subclass of: ProcessingStep
definition: PIV-specific action undertaken during PIV data handling from recording to processing.

PIV Recording
type: Class
subclass of: ProcessingStep
comment: Use schema:instrument or m4i:hasEmployedTool to related the used tools like camera and laser to the recording
definition: The process of performing the Particle Image Velocimetry experiment.

PIV Result Distribution
type: Class
subclass of: PIV Distribution
definition: A PIV result distribution containing displacements and optionally other derived variables

PIV Setup
type: Class
subclass of: Restriction
  some values from: Light Source
  on property: has part
subclass of: Restriction
  some values from: Optic Sensor
  on property: has part
subclass of: Restriction
  some values from: PIV Particle
  on property: has part

PIV Software
type: Class
subclass of: Software

PIV Validation
type: Class
subclass of: PIV Post Processing
definition: The process of validating an PIV solution.

Peak Search Method
type: Class
subclass of: Method
comment: Method fitting the sub pixel peak in the correlation signal.
example: Peak centroid, Parabolic peak fit or Gaussian peak fit.

Singlepass
type: Class
subclass of: Interrogation Method
definition: Standard single pass interrogation algorithm.

Synthetic PIV Particle
type: Class
subclass of: Tool
subclass of: Virtual Tool
definition: Refers to one or generally many synthetically generated (modelled) tracer particles, also called seeding particles. Its parameters should be described via m4i:hasParameter. The source code generating the particles should be stated via codemeta:hasSourceCode.

Temporal Variable
type: Class
subclass of: Text Variable
definition: A variable that expects a string of characters as a valu, which represent date times. The format to process the data is specified in the property pivmeta:timeFormat

Virtual Camera
type: Class
subclass of: Camera
subclass of: Virtual Tool
definition: A computational model of a digital camera. A set of parameters should be added using h4i:hasParameter and the source code relation using codemeta:hasSourceCode

Virtual Laser
type: Class
subclass of: Light Source
subclass of: Virtual Tool
definition: A virtual laser used in synthetic PIV codes.

Virtual PIV Setup
type: Class
subclass of: PIV Setup
definition: A simulation that relies on physics based models for a PIV Experiment.

Virtual Tool
type: Class
subclass of: Tool
definition: The virtual or computational object that helped the agent perform the action, e.g. John took a photo with his modelled camera.

Window Weighting Function
type: Class
subclass of: Concept

Intangible
type: Class
definition: A utility class that serves as the umbrella for a number of 'intangible' things such as quantities, structured values, etc.

software source code
type: Class
subclass of: CreativeWork
definition: Computer programming source code. Example: Full (compile ready) solutions, code snippet samples, scripts, templates.

Software
type: Class
subclass of: Tool

NdYAG laser
type: Class
subclass of: Laser
definition: Neodymium-doped yttrium aluminum garnet laser

Q38867
type: Class
comment: Class from wikidata representing a Laser

Image
type: NamedIndividual
type: DCMI Type
definition: A visual representation other than text.

AmountOfSubstancePerUnitArea
type: NamedIndividual
type: QuantityKind
description: Amount of Substance per unit area
applicable unit: per pixel
example: Typically used to describe the particle image density in a PIV image, also known as ppp (particle per pixel).
label: Amount of Substance per Unit Area

Blackman Window
type: NamedIndividual
type: Image Manipulation Method

DEHS
type: NamedIndividual
type: PIV Particle
definition: diethylhexyl sebacate

Experimental Image
type: NamedIndividual
type: DCMI Type

active
type: NamedIndividual
type: Flag Variable
has flag meaning: active
has flag value: 1

Gaussian Window
type: NamedIndividual
type: Window Weighting Function

Hamming Window
type: NamedIndividual
type: Window Weighting Function

Hann Window
type: NamedIndividual
type: Window Weighting Function

Interpolation
type: NamedIndividual
type: Outlier Replacement Scheme
definition: Method to replace vectors identified as invalid by interpolating from surrounding data.

left right flip
type: NamedIndividual
type: Image Manipulation Method

millimeter per pixel
type: NamedIndividual
type: Unit
description: Millimeters per pixel, representing the optical magnification where the length in millimeters corresponds to the number of pixels in the image.
has quantity kind: spatial resolution
symbol: mm/pixel

per pixel
type: NamedIndividual
type: Unit
description: A reciprocal unit of pixel.
has quantity kind: spatial resolution
symbol: 1/pixel
example: Typically used to describe the particle image density in a PIV image, also known as ppp (particle per pixel).

PIV data
type: NamedIndividual
type: DCMI Type
comment: Use this as dct:type of a dcat:Resource. See https://www.w3.org/TR/vocab-dcat-2/#classifying-dataset-types.
definition: Particle Image Velocimetry data, e.g. data resulting from PIV, PTV or other specialized methods.

PIV image
type: NamedIndividual
type: DCMI Type
definition: An image showing Particles illuminated by a laser from a Particle Image Velocimetry measurement.

Particle Image Velocimetry
type: NamedIndividual
type: Method
definition: Method to measure velocities in fluid.

Particle Tracking Velocimetry
type: NamedIndividual
type: Method
definition: A measurement technique to measure the velocity of particles.

re-evaluate with larger sample
type: NamedIndividual
type: Outlier Replacement Scheme

spatial resolution
type: NamedIndividual
type: QuantityKind
comment: A quantity kind representing length per pixel in an image.

split image
type: NamedIndividual
type: Image Manipulation Method

Square Window
type: NamedIndividual
type: Window Weighting Function

synthetic image
type: NamedIndividual
type: DCMI Type

top bottom flip
type: NamedIndividual
type: Image Manipulation Method

try lower order peaks
type: NamedIndividual
type: Outlier Replacement Scheme

Tukey Window
type: NamedIndividual
type: Window Weighting Function

Micro PIV
type: NamedIndividual
type: Method
definition: Microscopic PIV. Example Applications can be found in Raffel et al. (2018) "Particle Image Velocimetry: A Practical Guide", Springer, https://doi.org/10.1007/978-3-319-68852-7.