/// <summary>
/// read block and store them as signal samples for processing
/// </summary>
/// <param name="seek">seek to block</param>
/// <param name="count">blocks to read</param>
/// <returns></returns>
public static SignalSamples readBlocks(long seek, long count)
{
SignalSamples samples = new SignalSamples();
if (seek > blocksCount())
{
return(samples);
}
long cnt = 0;
if (seek < 0)
{
setPosition(0);
cnt = count + seek;
}
else
{
setPosition(seek);
cnt = count;
}
for (int i = 0; i < cnt; i++)
{
if (remainingBlocks() < 2)
{
return(samples);
}
readBlock(ref samples);
}
return(samples);
}
/// <summary>
/// load and filter signal
/// </summary>
/// <param name="slider">slider</param>
/// <returns></returns>
public static SignalSamples load(Slider slider)
{
// skip if file not exist
if (!FileHandler.available())
{
return(null);
}
// load samples
Settings set = Settings.instance();
int sampleRate = FileHandler.readSampleRate();
SignalSamples samples = FileHandler.readBlocks(slider.seek, slider.blocks);
samples = samples.Normalize();
samples.sampleRate = sampleRate;
// find signal amplitude
Signal deltaGreat = samples.FindMax() - samples.FindMin();
// 2x 12 hz filter
if (set.noise12Hz)
{
samples.Filter(12, sampleRate / 2, 1.3f);
samples.Filter(12, sampleRate / 2, 1.3f);
}
// 20 hz filter
if (set.noise20Hz)
{
samples.Filter(20, sampleRate / 2, 1.3f);
samples.Filter(20, sampleRate / 2, 1.3f);
}
// 45 hz filter
if (set.noise45Hz)
{
samples.Filter(45, sampleRate / 2, 1.3f);
}
// 50hz or 60hz noise
if (set.noiseCustom > 0)
{
samples.Filter(set.noiseCustom, sampleRate / 2, 1);
}
// notch filter
if (set.noiseNotch)
{
samples = FilterNotch.Process(samples, 400, 0.1f);
}
// find signal loss enerrgy amplitude
Signal deltaLess = samples.FindMax() - samples.FindMin();
// amplify loosed amplitude
samples.Amplify(deltaGreat, deltaLess);
// load file description
FileHandler.id = XmlClass <EcgStatistic> .Load(FileHandler.p + ".xml", SerializedFormat.Document);
return(samples);
}
/// <summary>
/// read single block as signal
/// </summary>
/// <param name="samples"></param>
private static void readBlock(ref SignalSamples samples)
{
byte[] header = io.ReadBytes(8);
double adcmax = 0x800000;
byte SDM = header[0];
byte R1 = header[1];
byte R2 = header[2];
byte R3 = header[3];
int odr = 102400 * SDM / R1 / R2 / R3;
if (R2 == 4 || R2 == 8)
{
if (R3 == 6 || R3 == 12)
{
adcmax = 0xF30000;
}
else
{
adcmax = 0x800000;
}
}
else if (R2 == 5)
{
if (R3 == 6 || R3 == 12)
{
adcmax = 0xB964F0;
}
else
{
adcmax = 0xC35000;
}
}
else if (R2 == 6)
{
if (R3 == 6 || R3 == 12)
{
adcmax = 0xE6A900;
}
else
{
adcmax = 0xF30000;
}
}
for (int i = 0; i < 56; i++)
{
double sample1 = ((Math.Pow(2, 16) * io.ReadByte() + Math.Pow(2, 8) * io.ReadByte() + io.ReadByte()) / adcmax - 0.5) * 4.8 / 3.5 * 1000;
double sample2 = ((Math.Pow(2, 16) * io.ReadByte() + Math.Pow(2, 8) * io.ReadByte() + io.ReadByte()) / adcmax - 0.5) * 4.8 / 3.5 * 1000;
double sample3 = ((Math.Pow(2, 16) * io.ReadByte() + Math.Pow(2, 8) * io.ReadByte() + io.ReadByte()) / adcmax - 0.5) * 4.8 / 3.5 * 1000;
Signal ss = new Signal()
{
lead1 = (float)sample1, lead2 = (float)sample2, lead3 = (float)sample3
};
samples.Add(ss);
}
}
/// <summary>
/// thread for faster analysing
/// </summary>
void run()
{
// skip if file not available
if (!FileHandler.available())
{
return;
}
progressBar1.Value = 0;
// load sample rate
sampleRate = FileHandler.readSampleRate();
// load samples
samples = FileHandler.load(slider1);
progressBar1.Value = 20;
Application.DoEvents();
bool fst = false;
// if signal was ecg
if (decg.Checked)
{
// set samples
graph1.samples = samples;
graph1.sampleRate = sampleRate;
graph1.ylabel = "mv";
}
else
{
graph1.samples = new SignalSamples();
graph1.samples.sampleRate = 0;
graph1.sampleRate = 0;
bool stop = false;
// initialize ecg arrays
int[] tr = new int[3];
int[] offset = new int[3];
List <float>[] sigz = new List <float> [3];
EcgCharacteristics[] last = new EcgCharacteristics[3];
EcgCharacteristics[] now = new EcgCharacteristics[3];
// define ecg arrays
for (int i = 0; i < 3; i++)
{
sigz[i] = new List <float>();
offset[i] = sampleRate;
// detect first ecg signal
last[i] = samples.FindDelta(i + 1, 0, offset[i]);
tr[i] = 0;
}
// loop until signal is end
do
{
for (int i = 0; i < 3; i++)
{
// detect second ecg signal
now[i] = samples.FindDelta(i + 1, last[i].lastCharacteristic(), offset[i]);
// find distrance between two pulses
offset[i] = Math.Abs(now[i]["R"].idx - last[i]["R"].idx);
// if the heart beat(pulse rate) between exact range
if (offset[i] > 0 && offset[i] < sampleRate)
{
// find heart beat sample rate
if (!fst)
{
graph1.samples.sampleRate += offset[i];
if (i == 2)
{
fst = true;
}
}
float hpr = 0;
// calculate ST line
if (dst.Checked)
{
hpr = (now[i]["ST"].value - now[i]["Q"].value);
}
else if (dpr.Checked) // calculate heart beat
{
hpr = 60.0f / (float)(offset[i] / (float)sampleRate);
}
sigz[i].Add(hpr);
}
else
{
// if pulse rate was not reliable set offset as default sample rate
offset[i] = sampleRate;
}
// if ecg data was not reliable try again
if (now[i]["c"].idx <= 0 || now[i]["T"].idx <= 0)
{
tr[i]++;
}
// set last ecg signal if signal was out of range
if (now[i].lastCharacteristic() <= last[i].lastCharacteristic())
{
now[i]["c"].idx = last[i].lastCharacteristic() + offset[i];
}
// skip if signal was out of range
if (now[i].lastCharacteristic() + offset[i] > samples.Count)
{
tr[i] = 40;
}
// set
last[i] = now[i];
}
// return when data was end
if (tr[0] > 30 && tr[1] > 30 && tr[2] > 30)
{
stop = true;
}
} while (!stop);
// find maximum signal range
int max = sigz[0].Count;
for (int i = 0; i < 3; i++)
{
if (sigz[i].Count > max)
{
max = sigz[i].Count;
}
}
// insert collected data as samples
for (int i = 0; i < max; i++)
{
Signal sig = new Signal();
for (int j = 0; j < 3; j++)
{
if (i < sigz[j].Count)
{
sig[j + 1] = sigz[j][i];
}
}
graph1.samples.Add(sig);
}
// show results
if (dpr.Checked)
{
graph1.ylabel = "";
}
else if (dst.Checked)
{
graph1.ylabel = "mv";
}
progressBar1.Value = 100;
graph1.samples.sampleRate = (int)((float)sampleRate / (float)graph1.samples.sampleRate / 3.0f + 1);
graph1.sampleRate = graph1.samples.sampleRate;
graph1.samples.NoiseReduction(3);
}
graph1.zoom = (float)graph1.samples.Count / (float)graph1.sampleRate;
graph1.Refresh();
working = false;
}
