private EEGSample GetSample(int i)
{
if (i >= csvData.Count) return null;
List<String> row = csvData[i];
EEGSample sample = new EEGSample();
sample.index = i;
sample.timestamp = Convert.ToInt64(row[timestampPosition]);
Electrode electrode;
int columnNo;
foreach (KeyValuePair<Electrode, int> column in columnNumbers)
{
electrode = column.Key;
columnNo = column.Value;
sample.eegValues.Add(electrode, Convert.ToDouble(row[columnNo], System.Globalization.CultureInfo.InvariantCulture));
}
sample.eyeX = Convert.ToDouble(row[eyeXColumnNo], System.Globalization.CultureInfo.InvariantCulture);
sample.eyeY = Convert.ToDouble(row[eyeYColumnNo], System.Globalization.CultureInfo.InvariantCulture);
return sample;
}
private EEGSample FindNextGoodSample(EEGSample startSample)
{
int i = startSample.index;
long timestampWanted = (long)(startSample.timestamp + (1000000 / sampleRate));
long bestDifferenceToWantedTimestamp = startSample.timestamp;
EEGSample bestSample = null;
// Überspringe aufeinanderfolgende Timestamps mit demselben Wert. Manchmal häufen die sich.
EEGSample nextSample = GetSample(i + 1);
while (nextSample != null && nextSample.timestamp == startSample.timestamp)
{
i++;
nextSample = GetSample(i + 1);
}
// Suche den nächsten Timestamp, der (entsprechend der angegebenen Sample-Rate) dem erwarteten Wert am nächsten kommt
for (int j = i + 1; j < (i + 5); j++)
{
nextSample = GetSample(j);
if (nextSample == null) return null;
long differenceToWantedTimestamp = Math.Abs(timestampWanted - nextSample.timestamp);
if (differenceToWantedTimestamp < bestDifferenceToWantedTimestamp)
{
bestDifferenceToWantedTimestamp = differenceToWantedTimestamp;
bestSample = nextSample;
}
}
return bestSample;
}