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Public Group

flowchart LR
  .nde[**.nde**]:::root --> Public["/Public*"]:::group
  Public["/Public*"] --> Setup["/Setup*"]:::dataset
  Public["/Public*"] --> Groups["/Groups"]:::group
  .nde@{ shape: text}
  classDef root fill:#fff
  classDef group fill:#ffc72c,stroke:#000000,color:#000000
  classDef dataset fill:#fff,stroke:#000000,color:#000000

The Public HDF5 group is mandatory and the structure of its subgroups is considered as standardized information (and its structure is described in the present documentation).

Setup dataset

The Setup HDF5 dataset is mandatory and contains all the metadata useful for retrieving the acquisition context and reading or processing the acquired datasets (probes, specimens, acquisitions units, etc.). This dataset is a string structured in a JSON format.

Groups group and subgroups

Avoid confusion

The Groups designation can be confusing, so pay attention to the difference betwen an HDF5 group (the equivalent of a folder in a filesystem) and the .nde Groups structure layer, which is the name of a specific HDF5 group defined in the .nde file format data model that can be accessed under the /Public/Groups path.

The Groups HDF5 group may contain inspection data but also other contextual information divided by inspection group. An inspection group corresponds to the combination of one or several probes and an acquisition strategy (such as a linear array and TFM for UT).

Datasets that contain inspection data are stored hierarchically using the following logic:

flowchart LR
  Groups["/Groups"]:::group --> GroupId["/[GroupId]"]
  GroupId["/[GroupId]"]:::group --> Datasets["/Datasets"]
  Datasets["/Datasets"]:::group --> DatasetId-DataClass["/[DatasetId-DataClass]"]:::dataset
  classDef root fill:#005cb9,stroke:#000000,color:#fff
  classDef group fill:#ffc72c,stroke:#000000,color:#000000
  classDef dataset fill:#fff,stroke:#000000,color:#000000

  • GroupId must be a unique integer identifying an inspection group.

  • DatasetId must be a unique integer within a group identifying a specific dataset.

  • DataClass must be a string attributed one of the supported values: AScanAmplitude, AScanStatus, TFMValue, or TFMStatus. It enables the quick identification of the type of data associated with a dataset. The additional FiringSource data class can be found in some Evident .nde files but this type of dataset is only used internally for the moment.

Note that the Groups HDF5 group structure matches the description of groups in the JSON formatted Setup dataset. Please refer to this section for more information on datasets structure.

Example

It results in the following structure in a typical case where the acquisition was performed with an OmniScan X3 or X4 flaw detector. See also the example files page.

flowchart LR
  Groups["/Groups"]:::group --> 0["/0"]
  0["/0"]:::group --> Datasets["/Datasets"]
  Datasets["/Datasets"]:::group --> 0-AScanAmplitude["/0-AScanAmplitude"]:::dataset
  Datasets["/Datasets"]:::group --> 1-AScanStatus["/1-AScanStatus"]:::dataset
  classDef root fill:#005cb9,stroke:#000000,color:#fff
  classDef group fill:#ffc72c,stroke:#000000,color:#000000
  classDef dataset fill:#fff,stroke:#000000,color:#000000