emaFormat.md

Introduction

This document describes the JSON data format that is used to represent EMA data.

Structure

The JSON file consists of a single map. In the following, we discuss the different components of the map that can be accessed by using the corresponding keys.

channels

This entry of the map contains another map that describes the data associated to the individual coils of the EMA recordings.

position

This part of an EMA coil consists of a list of positions. Each position describes the coordinate of the EMA coil at a specific time frame. The coordinate itself is stored in serialized manner. Given a time index timeIndex and the position array position, we can access the coordinate entries as follows:

double x = position[timeIndex * 3 + 0];
double y = position[timeIndex * 3 + 1];
double z = position[timeIndex * 3 + 2];

RMS

This component of the EMA coil map contains a list of RMS values that correspond to the individual time frames.

timestamps

This part of the main map contains the list of time stamps that belong to the time frames.

samplingFrequency

This value describes the sampling frequency of the data in Hertz.

Example

An example of such a JSON file is given by:

{

    "channels" : {

        "TongueTip" : {

            "position" : [
                0, 1, 2,
                1, 1, 2,
                2, 2, 3
            ],

            "RMS" : [
                0.2,
                0.4,
                0.2
            ]

        },

        "TongueBack" : {

            "position" : [
                5, 5, 7,
                6, 9, 6,
                7, 8, 1
            ],

            "RMS" : [
                0.2,
                0.4,
                2
            ]

        }
    },
    "timestamps" : [
        0.005,
        0.010,
        0.015
    ],

    "samplingFrequency" : 200

}