File structure

Technologies

The .nde file format is built on the HDF5 opensource library. Visit https://www.hdfgroup.org for more information.

The HDF5 data hierarchy is complemented by Java Script Object Notation (JSON) in two ways:

·        JSON file is embedded directly in the file structure, setup parameters are obtained in an easy-to-read way and are quick to access.

·        JSON schema files are provided to manage file compatibility.

General Structure

The .nde file format provides a relatively simple file structure with a container for nonstandardized application usage (application) and a standardized container for the data and setup or contextual information that describes the data (domain).

Application
Description	A proprietary acquisition software-specific section. This section is not meant for use by .nde readers and can be structured as per the acquisition software’s specifications.
Open	No.
Usage	Each application that creates/modifies the data file can add specific information here. This container can be used as deemed necessary by the application software that creates the .nde file, including but not limited to storing setup information, customized data, or metadata, etc. This section is not used for information that should be shared between applications.

Domain
Description	Includes the standardized dataset information and standardized setup information described in an embedded JSON file.
Open	Yes.
Usage	The information in this section is standardized and versioned.

Interpreting the Data

Instead of exploiting HDF5 attributes the contextual or setup information that is essential to completely interpret the data is contained in the setup JSON file.

This embedded JSON file provides an easy-to-read way to obtain all setup information and is quick to access in part because of its flat structure in comparison to exploiting the HDF attributes at each level of the data tree.

Each group contains a dataset description and configuration described in the JSON.

JSON group object example containing dataset and a phased array configuration:

{
 "groups": [
    {
      "id": 0,
      "name": "GR-1",
      "paut": {                   // <---- Phased Array Configuration
        "beams": [
            //...
        ]        
        //...
      },
      "dataset": {                // <---- dataSet Information
        "ascan": {
          "amplitude": {
            "dataSampling": {...},
            "dataValue": {...},
            "path": "/Domain/DataGroups/0/Datasets/0/Amplitude",
            "dimensions": [...]
          },
          "status": {
            "dataValue": {...},
            "path": "/Domain/DataGroups/0/Datasets/0/Status",
            "dimensions": [...]
          }
        },
        "storageMode": "Paintbrush"
      }
    }
  ]
}

Scenarios and Objects

Designed to offer both simplicity and extensibility, the .nde file format includes the concepts of scenarios and objects.

Scenarios : Defines by convention certain aspects of the configuration, notably the reference coordinate system.

Objects : Describes components such as supported probe types or focal law configurations at the appropriate level of complexity.