/// <summary>
/// Despike the channel from lower outliers
/// </summary>
/// <param name="name">channel name in the source file</param>
/// <param name="threshold">relative value of threshold</param>
public void DespikeFromLow(string name, double threshold)
{
Oilfield_Channel src_index = m_src.GetIndex();
if (src_index == null)
{
return;
}
Oilfield_Channel src_channel = m_src.GetChannel(name);
if (src_channel == null)
{
return;
}
// locate upper and lower boundaries and determine threshold
DataStart = Double.NaN;
DataEnd = Double.NaN;
DataStartIndex = -1;
DataEndIndex = -1;
if (!src_channel.LocateDataBoundaries(src_index))
{
return;
}
DataStart = src_channel.DataStart;
DataEnd = src_channel.DataEnd;
DataStartIndex = src_channel.DataStartIndex;
DataEndIndex = src_channel.DataEndIndex;
double tr = src_channel.Average * threshold;
// remove all values below threshhold
for (int i = 0; i < src_channel.Data.Count; i++)
{
double d = src_channel.Data[i];
if (Double.IsNaN(d))
{
continue;
}
if (d < tr)
{
src_channel.Data[i] = Double.NaN;
}
}
// compute average of the remaining and fill the gaps
double avr = src_channel.GetAverage(DataStartIndex, DataEndIndex);
for (int i = 0; i < src_channel.Data.Count; i++)
{
if (i < DataStartIndex || i > DataEndIndex)
{
continue;
}
if (Double.IsNaN(src_channel.Data[i]))
{
src_channel.Data[i] = avr;
}
}
}
/// <summary>
/// Filter the channel using Ganning Algorithm
/// </summary>
/// <param name="name">channel name in the source file</param>
/// <param name="n">half-size of filter</param>
/// <param name="k">number of rejected values</param>
public void FilterChannelGunning(string name, int n, int k)
{
Oilfield_Channel src_index = m_src.GetIndex();
if (src_index == null)
{
return;
}
Oilfield_Channel src_channel = m_src.GetChannel(name);
if (src_channel == null)
{
return;
}
// locate upper and lower boundaries
DataStart = Double.NaN;
DataEnd = Double.NaN;
DataStartIndex = -1;
DataEndIndex = -1;
if (!src_channel.LocateDataBoundaries(src_index))
{
return;
}
DataStart = src_channel.DataStart;
DataEnd = src_channel.DataEnd;
DataStartIndex = src_channel.DataStartIndex;
DataEndIndex = src_channel.DataEndIndex;
// perform Gunning filtering
int l = src_channel.Data.Count;
List <double> buff = new List <double>(l);
buff.AddRange(src_channel.Data);
for (int i = 0; i < l; i++)
{
src_channel.Data[i] = Double.NaN;
if (i < DataStartIndex)
{
continue;
}
if (i > DataEndIndex)
{
continue;
}
List <double> tmp = new List <double>((n << 1) + 1);
for (int j = i - n; j <= i + n; j++)
{
if (j < 0 || j >= l)
{
continue;
}
if (Double.IsNaN(buff[j]))
{
continue;
}
tmp.Add(buff[j]);
}
if (tmp.Count <= 0)
{
continue;
}
tmp.Sort();
int kk = k;
while (tmp.Count < (kk + 5 + kk))
{
kk--;
}
double avearge = 0.0;
double avearge_count = 0.0;
for (int j = kk; j < tmp.Count - kk; j++)
{
avearge += tmp[j];
avearge_count += 1.0;
}
if (avearge_count <= 0.0)
{
continue;
}
src_channel.Data[i] = avearge / avearge_count;
}
}
/// <summary>
/// Interpolate the channel
/// </summary>
/// <param name="name">channel name in the source file</param>
/// <param name="isAzimuth">st to true is wrap-around is needed</param>
private void InterpolateChannelRaw(string name, bool isAzimuth)
{
Oilfield_Channel src_index = m_src.GetIndex();
if (src_index == null)
{
return;
}
Oilfield_Channel src_channel = m_src.GetChannel(name);
if (src_channel == null)
{
return;
}
// locate upper and lower boundaries
DataStart = Double.NaN;
DataEnd = Double.NaN;
DataStartIndex = -1;
DataEndIndex = -1;
if (!src_channel.LocateDataBoundaries(src_index))
{
return;
}
DataStart = src_channel.DataStart;
DataEnd = src_channel.DataEnd;
DataStartIndex = src_channel.DataStartIndex;
DataEndIndex = src_channel.DataEndIndex;
// perform interpolation for missing lines
for (int i = 0; i < src_channel.Data.Count; i++)
{
if (!Double.IsNaN(src_channel.Data[i]))
{
continue;
}
if (i < DataStartIndex)
{
continue;
}
if (i > DataEndIndex)
{
continue;
}
double d = Convert.ToDouble(i);
double depth1 = 0.0;
double a1 = 0.0;
for (int j = i; j >= 0; j--)
{
if (Double.IsNaN(src_channel.Data[j]))
{
continue;
}
depth1 = Convert.ToDouble(j);
a1 = src_channel.Data[j];
break;
}
double depth2 = 1.0;
double a2 = 0.0;
for (int j = i; j < src_channel.Data.Count; j++)
{
if (Double.IsNaN(src_channel.Data[j]))
{
continue;
}
depth2 = Convert.ToDouble(j);
a2 = src_channel.Data[j];
break;
}
double dd = depth2 - depth1;
if (Math.Abs(dd) < 0.001)
{
continue;
}
double w1 = (depth2 - d) / dd;
double w2 = (d - depth1) / dd;
if (isAzimuth)
{
if (a1 > 270.0 && a2 < 90.0)
{
a1 -= 360.0;
}
if (a1 < 90.0 && a2 > 270.0)
{
a2 -= 360.0;
}
}
src_channel.Data[i] = w1 * a1 + w2 * a2;
if (isAzimuth)
{
while (src_channel.Data[i] < 0.0)
{
src_channel.Data[i] += 360.0;
}
while (src_channel.Data[i] >= 360.0)
{
src_channel.Data[i] -= 360.0;
}
}
}
}