Data Mappings¶

Typearray

Independently of the nondestructive evaluation method, there is always a need to relate acquisition data to the inspected specimen in terms of positioning. There exist, however, diametrically opposed use cases calling for adapted methods to achieve this relationship.

The dataMappings array specifies how inspection data relates to the specimen. Two mapping strategies are supported:

discreteGrid — Data is mapped onto a regular spatial grid defined by U/V coordinates. Suited to scanner-based acquisitions where probe position is known at each acquisition point (e.g. PAUT weld inspections, ECA inspections with embedded encoder).
allCycle 4.3.0 — Every acquisition cycle is stored along with its corresponding encoder position information. Suited to acquisitions where probe trajectory is irregular or must be reconstructed in post-processing (e.g. ECT with rotary encoder, robotic PAUT).

dataMappings¶

Typearray

The dataMappings array describes the relationship between data and the specimen through the scenario coordinate system.

Property	Type	Description
id `required`	integer	Unique data mapping id in the JSON structure
specimenId `required`	integer	Unique specimen id in the JSON structure
surfaceId `required`	integer	Unique surface id in the JSON structure
One of the following `required` mapping strategy objects: discreteGrid allCycle	object

Related objects: specimens, surfaces

discreteGrid¶

Typeobject

The discreteGrid object describes the properties of the scanning grid and its dimensions.

Property	Type	Description
scanPattern `required`	string	One of the following scan patterns: `OneLineScan` or `RasterScan`
uCoordinateOrientation `required`	string	One of the following U coordinate orientations: `Around`, `Along`, `Width`, or `Length`
dimensions `required`	array	An array of UCoordinate, VCoordinate, and/or Polar axis objects

Related objects: specimens, surfaces

UCoordinate¶

Typeobject

The UCoordinate object describes the discrete grid U dimension.

Property	Type	Unit	Description
axis `required`	string	-	The name of the axis, necessarily `UCoordinate`
quantity `required`	integer	-	Size of the grid against the U axis
resolution `required`	number	m	Space allocated to one data point along this axis
offset	number	m	Axis offset
motionDeviceId	integer	-	Reference to the unique id of a motionDevice object
name	string	-	Name or reference of this dimension
unit	string	-	Unit of the axis values, e.g. `Meter`, `Degree`, `Revolution`
lastCellRewrited	integer	-	When the acquisition is performed in time mode (no encoder), this axis is a circular buffer in which the first position is given in lastCellRewrited

Related objects: motionDevice

VCoordinate¶

Typeobject

The VCoordinate object describes the discrete grid V dimension.

Property	Type	Unit	Description
axis `required`	string	-	The name of the axis, necessarily `VCoordinate`
quantity `required`	integer	-	Size of the grid against the V axis
resolution `required`	number	m	Space allocated to one data point along this axis
offset	number	m	Axis offset
motionDeviceId	integer	-	Reference to the unique id of a motionDevice object
name	string	-	Name or reference of this dimension
unit	string	-	Unit of the axis values, e.g. `Meter`, `Degree`, `Revolution`

Related objects: motionDevice

Polar¶

Typeobject 4.3.0

The Polar object describes a discrete grid angular dimension, used for rotational scanning configurations (e.g. ECT with rotary encoder).

Property	Type	Unit	Description
axis `required`	string	-	The name of the axis, necessarily `Polar`
quantity `required`	integer	-	Size of the grid against the polar axis
resolution `required`	number	degree	Angular space allocated to one data point along this axis
offset	number	degree	Angular axis offset
motionDeviceId	integer	-	Reference to the unique id of a motionDevice object
name	string	-	Name or reference of this dimension
unit	string	-	Unit of the axis values, e.g. `Meter`, `Degree`, `Revolution`

Related objects: motionDevice

allCycle¶

Typeobject 4.3.0

The allCycle mapping stores every acquisition cycle individually along with the encoder position recorded at that cycle. Acquisition cycles are uniformly spaced in time at the acquisition rate specified in acquisitionUnits. A separate dataset is created for each motion device.

Property	Type	Description
datasets	array	A datasets array describing encoder positioning data

datasets¶

Typearray

Property	Type	Description
id	integer	Unique dataset id within the `allCycle` object
dataClass	string	Type of data stored, in this case, data class is `Encoder`
dataValue `required`	object	A dataValue object describing the encoding of stored values
dimensions `required`	array	A dimensions array — always a single `AcquisitionCycle` dimension
path	string	Path to the dataset in the HDF5 structure

dataValue¶

Typeobject

Property	Type	Description
unit `required`	string	Unit of the stored values, e.g. `Step`, `Meter`, or `Degree`
unitMin `required`	number	Minimum value representable in the stored integer unit
unitMax `required`	number	Maximum value representable in the stored integer unit
min `required`	number	Minimum physical value mapped to `unitMin`
max `required`	number	Maximum physical value mapped to `unitMax`

dimensions¶

Typearray

Because a separate dataset is created for each motion device, allCycle datasets are always 1D.

Property	Type	Description
axis `required`	string	Always `AcquisitionCycle`
quantity `required`	integer	Total number of cycles in the dataset
motionDeviceId	integer	Reference to the unique id of a motionDevice used to populate the dataset
orientation	string	Specimen axis on which the encoder is aligned, one of `UCoordinate` or `VCoordinate`
lastCellRewrited	integer	When the acquisition is performed in time mode (no encoder), this axis is a circular buffer in which the first position is given in lastCellRewrited

Examples¶

discreteGridallCycle

"dataMappings": [
  {
    "id": 0,
    "specimenId": 0,
    "surfaceId": 0,
    "discreteGrid": {
      "scanPattern": "OneLineScan",
      "uCoordinateOrientation": "Length",
      "dimensions": [
        {
          "axis": "UCoordinate",
          "motionDeviceId": 0,
          "name": "Scan",
          "offset": 0.042,
          "quantity": 45,
          "resolution": 0.001
        }
      ]
    }
  },
  {
  "id": 1,
  "specimenId": 0,
  "surfaceId": 0,
  "discreteGrid": {
    "scanPattern": "RasterScan",
    "uCoordinateOrientation": "Around",
    "dimensions": [
      {
        "motionDeviceId": 0,
        "axis": "UCoordinate",
        "offset": 0,
        "quantity": 250,
        "resolution": 1,
        "unit": "Revolution"
      },
      {
        "motionDeviceId": 1,
        "axis": "Polar",
        "offset": 0,
        "quantity": 600,
        "resolution": 0.6,
        "unit": "Degree"
      }
    ]
  }
}
]

"dataMappings": [
  {
    "id": 0,
    "specimenId": 0,
    "surfaceId": 0,
    "allCycle": {
      "datasets": [
        {
          "id": 0,
          "dataClass": "Encoder",
          "dataValue": {
            "unit": "Step",
            "unitMax": 2147483647,
            "unitMin": -2147483648,
            "max": 2147483647,
            "min": -2147483648
          },
          "dimensions": [
            {
              "axis": "AcquisitionCycle",
              "quantity": 5261,
              "orientation": "UCoordinate",
              "motionDeviceId": 0
            }
          ],
          "path": "/Public/DataMappings/0/Datasets/0-Encoder"
        }
      ]
    }
  }
]