private void timer1_Tick(object sender, EventArgs e)
{
string line;
if (!m_bPaused && m_bInited && m_nStep >= 0 && m_srLog != null)
{
++m_nStep;
label7.Text = m_nStep.ToString();
int count = 0;
int nTempSize = 0;
while ((line = m_srLog.ReadLine()) != null)
{
Match match = Regex.Match(line, @"HR=(\d+), SP=(\d+)");
int time = -1, red = -1, ir = -1, hr = -1, sp = -1;
bool found_rawdata = false, found_hrsp = false;
if (match.Success && match.Groups.Count == 3)
{
found_hrsp = true;
hr = Convert.ToInt32(match.Groups[1].Value);
sp = Convert.ToInt32(match.Groups[2].Value);
chart1.Series["HR"].Points.AddXY(m_nLastTimeStamp, hr);
chart1.Series["SP"].Points.AddXY(m_nLastTimeStamp, sp);
// Original values
label4.Text = "HR = " + hr.ToString() + ", SP = " + sp.ToString();
}
else
{
match = Regex.Match(line, @"time=(\d+), red=(\d+), ir=(\d+)");
if (match.Success && match.Groups.Count == 4)
{
found_rawdata = true;
}
else
{
// CSV type
match = Regex.Match(line, @"\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)");
if (match.Success && match.Groups.Count == 4)
{
found_rawdata = true;
}
}
if (found_rawdata)
{
time = Convert.ToInt32(match.Groups[1].Value);
red = Convert.ToInt32(match.Groups[2].Value);
ir = Convert.ToInt32(match.Groups[3].Value);
if (count < MAX_TEMP_SIZE)
{
m_temp_red_buffer[count] = red;
m_temp_ir_buffer[count] = ir;
m_temp_time_buffer[count] = time;
nTempSize = count + 1;
chart1.Series["Red"].Points.AddXY(time, red);
chart1.Series["IR"].Points.AddXY(time, ir);
}
m_nLastTimeStamp = time;
++count;
}
}
if (found_hrsp || count > 100)
{
int nTotalSize = m_nBufferSize + nTempSize;
if (nTempSize >= Algorithm30102.BUFFER_SIZE)
{
// Temp is enough
int nLeftShift = nTempSize - Algorithm30102.BUFFER_SIZE;
for (int i = 0; i < Algorithm30102.BUFFER_SIZE; ++i)
{
m_red_buffer[i] = m_temp_red_buffer[i + nLeftShift];
m_ir_buffer[i] = m_temp_ir_buffer[i + nLeftShift];
m_time_buffer[i] = m_temp_time_buffer[i + nLeftShift];
}
m_nBufferSize = Algorithm30102.BUFFER_SIZE;
}
else if (nTotalSize > Algorithm30102.BUFFER_SIZE)
{
// Need to left-shift the most recent data on the system buffer
int nKeep = Algorithm30102.BUFFER_SIZE - nTempSize;
int nLeftShift = m_nBufferSize - nKeep;
for (int i = 0; i < nKeep; ++i)
{
m_red_buffer[i] = m_red_buffer[i + nLeftShift];
m_ir_buffer[i] = m_ir_buffer[i + nLeftShift];
m_time_buffer[i] = m_time_buffer[i + nLeftShift];
}
// Then copy the whole temp to fill the system buffer
for (int i = nKeep; i < Algorithm30102.BUFFER_SIZE; ++i)
{
m_red_buffer[i] = m_temp_red_buffer[i - nKeep];
m_ir_buffer[i] = m_temp_ir_buffer[i - nKeep];
m_time_buffer[i] = m_temp_time_buffer[i - nKeep];
}
m_nBufferSize = Algorithm30102.BUFFER_SIZE;
}
else
{
// Just add the temp to the system buffer
for (int i = m_nBufferSize; i < nTotalSize; ++i)
{
m_red_buffer[i] = m_temp_red_buffer[i - m_nBufferSize];
m_ir_buffer[i] = m_temp_ir_buffer[i - m_nBufferSize];
m_time_buffer[i] = m_temp_time_buffer[i - m_nBufferSize];
}
m_nBufferSize = nTotalSize;
}
int window = Convert.ToInt32(textBox1.Text);
if (window < 100)
{
window = 100;
}
else if (window > Algorithm30102.BUFFER_SIZE)
{
window = Algorithm30102.BUFFER_SIZE;
}
textBox1.Text = window.ToString();
if (m_nBufferSize >= window)
{
Debug.Assert(m_nBufferSize <= Algorithm30102.BUFFER_SIZE);
int nNewHR = -1, nNewSP = -1;
bool bHRValid, bSPValid;
try
{
int nStart = m_nBufferSize - window;
int nSelected = comboBox1.SelectedIndex, sr = 100;
if (nSelected == 0)
{
sr = 50;
}
else if (nSelected == 1)
{
sr = 100;
}
else if (nSelected == 2)
{
sr = 200;
}
RData rdata = new RData();
m_alg.maxim_heart_rate_and_oxygen_saturation(sr, m_ir_buffer.Skip(nStart), window,
m_red_buffer.Skip(nStart), out nNewSP, out bSPValid, out nNewHR,
out bHRValid, rdata);
for (int i = 0; i < rdata.m_size; ++i)
{
chart1.Series["AD for Red"].Points.AddXY(m_time_buffer[nStart + rdata.m_red_indices[i]],
rdata.m_red_ratios[i]);
chart1.Series["AD for IR"].Points.AddXY(m_time_buffer[nStart + rdata.m_ir_indices[i]],
rdata.m_ir_ratios[i]);
}
}
catch
{
bHRValid = bSPValid = false;
}
if (!bHRValid)
{
nNewHR = -1;
}
if (!bSPValid)
{
nNewSP = -1;
}
if (nNewHR > 20 && nNewHR <= 200)
{
if (m_hr_filter.AddPoint((double)nNewHR))
{
m_bHasHRData = true;
}
else
{
nNewHR = -1;
}
}
else
{
nNewHR = -1;
}
if (m_bHasHRData)
{
nNewHR = (int)Math.Round(m_hr_filter.GetValue());
}
if (nNewSP > 50 && nNewSP <= 100)
{
if (m_sp_filter.AddPoint((double)nNewSP))
{
m_bHasSPData = true;
}
else
{
nNewSP = -1;
}
}
else
{
nNewSP = -1;
}
if (m_bHasSPData)
{
nNewSP = (int)Math.Round(m_sp_filter.GetValue());
}
label3.Text = "HR = " + nNewHR.ToString() + ", SP = " + nNewSP.ToString();
if (nNewHR > 0)
{
chart1.Series["newHR"].Points.AddXY(m_nLastTimeStamp, nNewHR);
}
if (nNewSP > 0)
{
chart1.Series["newSP"].Points.AddXY(m_nLastTimeStamp, nNewSP);
}
}
else
{
label3.Text = "Not enough raw data";
}
break;
}
}
if (line == null) // EOF
{
button2.Enabled = true;
button3.Enabled = false;
button4.Enabled = false;
m_srLog.Close();
m_srLog = null;
m_nStep = -1;
timer1.Stop();
}
}
}
int[] an_y = new int [BUFFER_SIZE]; //red
/**
* \brief Calculate the heart rate and SpO2 level
* \par Details
* By detecting peaks of PPG cycle and corresponding AC/DC of red/infra-red signal, the ratio for the SPO2 is computed.
* Since this algorithm is aiming for Arm M0/M3. formaula for SPO2 did not achieve the accuracy due to register overflow.
* Thus, accurate SPO2 is precalculated and save longo uch_spo2_table[] per each ratio.
*
* \param[in] sr - Sample rate
* \param[in] *pun_ir_buffer - IR sensor data buffer
* \param[in] n_ir_buffer_length - IR sensor data buffer length
* \param[in] *pun_red_buffer - Red sensor data buffer
* \param[out] *pn_spo2 - Calculated SpO2 value
* \param[out] *pch_spo2_valid - 1 if the calculated SpO2 value is valid
* \param[out] *pn_heart_rate - Calculated heart rate value
* \param[out] *pch_hr_valid - 1 if the calculated heart rate value is valid
*
* \retval None
*/
public void maxim_heart_rate_and_oxygen_saturation(int sr, IEnumerable <int> pun_ir_buffer_IEnum, int n_ir_buffer_length, IEnumerable <int> pun_red_buffer_IEnum, out int pn_spo2, out bool pch_spo2_valid,
out int pn_heart_rate, out bool pch_hr_valid, RData rdata)
{
int[] pun_ir_buffer = pun_ir_buffer_IEnum.ToArray();
int[] pun_red_buffer = pun_red_buffer_IEnum.ToArray();
int un_ir_mean, un_only_once;
int k, n_i_ratio_count;
int i, s, m, n_exact_ir_valley_locs_count, n_middle_idx;
int n_th1, n_npks, n_c_min;
int[] an_ir_valley_locs = new int[15];
int[] an_exact_ir_valley_locs = new int[15];
int[] an_dx_peak_locs = new int[15];
int n_peak_interval_sum;
int n_y_ac, n_x_ac;
int n_spo2_calc;
int n_y_dc_max, n_x_dc_max;
int n_y_dc_max_idx = -1, n_x_dc_max_idx = -1;
int[] an_ratio = new int[5];
int n_ratio_average, n_nume, n_denom;
Debug.Assert(pun_red_buffer.Length <= pun_ir_buffer.Length);
Debug.Assert(n_ir_buffer_length <= pun_ir_buffer.Length);
// Remove DC of ir signal
un_ir_mean = 0;
for (k = 0; k < n_ir_buffer_length; k++)
{
un_ir_mean += pun_ir_buffer[k];
}
un_ir_mean = un_ir_mean / n_ir_buffer_length;
for (k = 0; k < n_ir_buffer_length; k++)
{
an_x[k] = pun_ir_buffer[k] - un_ir_mean;
}
// 4 pt Moving Average
for (k = 0; k < n_ir_buffer_length - MA4_SIZE; k++)
{
n_denom = (an_x[k] + an_x[k + 1] + an_x[k + 2] + an_x[k + 3]);
an_x[k] = n_denom / (int)4;
}
// Get difference of smoothed IR signal
for (k = 0; k < n_ir_buffer_length - MA4_SIZE - 1; k++)
{
an_dx[k] = (an_x[k + 1] - an_x[k]);
}
// 2-pt Moving Average to an_dx
for (k = 0; k < n_ir_buffer_length - MA4_SIZE - 2; k++)
{
an_dx[k] = (an_dx[k] + an_dx[k + 1]) / 2;
}
// Hamming window: flip wave form so that we can detect valley with peak detector
for (i = 0; i < n_ir_buffer_length - HAMMING_SIZE - MA4_SIZE - 2; i++)
{
s = 0;
for (k = i; k < i + HAMMING_SIZE; k++)
{
s -= an_dx[k] * auw_hamm[k - i];
}
an_dx[i] = s / (int)1146; // divide by sum of auw_hamm
}
n_th1 = 0; // threshold calculation
for (k = 0; k < n_ir_buffer_length - HAMMING_SIZE; k++)
{
n_th1 += ((an_dx[k] > 0) ? an_dx[k] : ((int)0 - an_dx[k]));
}
n_th1 = n_th1 / (n_ir_buffer_length - HAMMING_SIZE);
// Peak location is acutally index for sharpest location of raw signal since we flipped the signal
maxim_find_peaks(an_dx_peak_locs, out n_npks, an_dx, n_ir_buffer_length - HAMMING_SIZE, n_th1, 8, 5);//peak_height, peak_distance, max_num_peaks
n_peak_interval_sum = 0;
if (n_npks >= 2)
{
for (k = 1; k < n_npks; k++)
{
n_peak_interval_sum += (an_dx_peak_locs[k] - an_dx_peak_locs[k - 1]);
}
n_peak_interval_sum = n_peak_interval_sum / (n_npks - 1);
// Each data point represent 1/sr second in time so peak internal in seconds is
// n_peak_interval_sum * (1 / sr).
// The heart rate is 60 / peak interval = 60 * sr / n_peak_interal_sum
pn_heart_rate = (int)(60 * sr / n_peak_interval_sum); // Beats per minutes
pch_hr_valid = true;
}
else
{
pn_heart_rate = -999;
pch_hr_valid = false;
}
for (k = 0; k < n_npks; k++)
{
an_ir_valley_locs[k] = an_dx_peak_locs[k] + HAMMING_SIZE / 2;
}
// Raw value : RED(=y) and IR(=X)
// We need to assess DC and AC value of ir and red PPG.
for (k = 0; k < n_ir_buffer_length; k++)
{
an_x[k] = pun_ir_buffer[k];
an_y[k] = pun_red_buffer[k];
}
// Find precise min near an_ir_valley_locs
n_exact_ir_valley_locs_count = 0;
for (k = 0; k < n_npks; k++)
{
un_only_once = 1;
m = an_ir_valley_locs[k];
n_c_min = 16777216; //2^24;
if (m + 5 < n_ir_buffer_length - HAMMING_SIZE && m - 5 > 0)
{
for (i = m - 5; i < m + 5; i++)
{
if (an_x[i] < n_c_min)
{
if (un_only_once > 0)
{
un_only_once = 0;
}
n_c_min = an_x[i];
an_exact_ir_valley_locs[k] = i;
}
}
if (un_only_once == 0)
{
n_exact_ir_valley_locs_count++;
}
}
}
if (n_exact_ir_valley_locs_count < 2)
{
pn_spo2 = -999; // do not use SPO2 since signal ratio is out of range
pch_spo2_valid = false;
return;
}
// 4 pt MA
for (k = 0; k < n_ir_buffer_length - MA4_SIZE; k++)
{
an_x[k] = (an_x[k] + an_x[k + 1] + an_x[k + 2] + an_x[k + 3]) / (int)4;
an_y[k] = (an_y[k] + an_y[k + 1] + an_y[k + 2] + an_y[k + 3]) / (int)4;
}
// Using an_exact_ir_valley_locs , find ir-red DC andir-red AC for SPO2 calibration ratio
// Finding AC/DC maximum of raw ir * red between two valley locations
n_ratio_average = 0;
n_i_ratio_count = 0;
for (k = 0; k < 5; k++)
{
an_ratio[k] = 0;
}
for (k = 0; k < n_exact_ir_valley_locs_count; k++)
{
if (an_exact_ir_valley_locs[k] > n_ir_buffer_length)
{
pn_spo2 = -999; // do not use SPO2 since valley loc is out of range
pch_spo2_valid = false;
return;
}
}
// Find max between two valley locations
// and use ratio betwen AC compoent of Ir & Red and DC compoent of Ir & Red for SPO2
for (k = 0; k < n_exact_ir_valley_locs_count - 1; k++)
{
n_y_dc_max = -16777216;
n_x_dc_max = -16777216;
if (an_exact_ir_valley_locs[k + 1] - an_exact_ir_valley_locs[k] > 10)
{
for (i = an_exact_ir_valley_locs[k]; i < an_exact_ir_valley_locs[k + 1]; i++)
{
if (an_x[i] > n_x_dc_max)
{
n_x_dc_max = an_x[i]; n_x_dc_max_idx = i;
}
if (an_y[i] > n_y_dc_max)
{
n_y_dc_max = an_y[i]; n_y_dc_max_idx = i;
}
}
n_y_ac = (an_y[an_exact_ir_valley_locs[k + 1]] - an_y[an_exact_ir_valley_locs[k]]) * (n_y_dc_max_idx - an_exact_ir_valley_locs[k]); //red
n_y_ac = an_y[an_exact_ir_valley_locs[k]] + n_y_ac / (an_exact_ir_valley_locs[k + 1] - an_exact_ir_valley_locs[k]);
n_y_ac = an_y[n_y_dc_max_idx] - n_y_ac; // subracting linear DC compoenents from raw
n_x_ac = (an_x[an_exact_ir_valley_locs[k + 1]] - an_x[an_exact_ir_valley_locs[k]]) * (n_x_dc_max_idx - an_exact_ir_valley_locs[k]); // ir
n_x_ac = an_x[an_exact_ir_valley_locs[k]] + n_x_ac / (an_exact_ir_valley_locs[k + 1] - an_exact_ir_valley_locs[k]);
n_x_ac = an_x[n_y_dc_max_idx] - n_x_ac; // subracting linear DC compoenents from raw
n_nume = (n_y_ac * n_x_dc_max) >> 7; //prepare X100 to preserve floating value
n_denom = (n_x_ac * n_y_dc_max) >> 7;
if (n_denom > 0 && n_i_ratio_count < 5 && n_nume != 0)
{
rdata.m_red_ratios[rdata.m_size] = 10000 * n_y_ac / n_y_dc_max;
rdata.m_red_indices[rdata.m_size] = n_y_dc_max_idx;
rdata.m_ir_ratios[rdata.m_size] = 10000 * n_x_ac / n_x_dc_max;
rdata.m_ir_indices[rdata.m_size] = n_x_dc_max_idx;
++rdata.m_size;
an_ratio[n_i_ratio_count] = (n_nume * 100) / n_denom; //formular is ( n_y_ac *n_x_dc_max) / ( n_x_ac *n_y_dc_max) ;
n_i_ratio_count++;
}
}
}
maxim_sort_ascend(an_ratio, n_i_ratio_count);
n_middle_idx = n_i_ratio_count / 2;
if (n_middle_idx > 1)
{
n_ratio_average = (an_ratio[n_middle_idx - 1] + an_ratio[n_middle_idx]) / 2; // use median
}
else
{
n_ratio_average = an_ratio[n_middle_idx];
}
if (n_ratio_average > 2 && n_ratio_average < 184)
{
n_spo2_calc = uch_spo2_table[n_ratio_average];
pn_spo2 = n_spo2_calc;
pch_spo2_valid = true;// float_SPO2 = -45.060*n_ratio_average* n_ratio_average/10000 + 30.354 *n_ratio_average/100 + 94.845 ; // for comparison with table
}
else
{
pn_spo2 = -999; // do not use SPO2 since signal ratio is out of range
pch_spo2_valid = false;
}
}