Yu anning / Mbed 2 deprecated LPC_MAX30102

the MAX30102 driver for LPC1768 board

Dependencies:   mbed

algorithm/algorithm.cpp@0:82a90765baa2, 2018-10-26 (annotated)

Committer:
anning865
Date:
Fri Oct 26 10:30:22 2018 +0000
Revision:
0:82a90765baa2
The MAX30102 driver for LPC1768

Who changed what in which revision?

UserRevisionLine numberNew contents of line
anning865 0:82a90765baa2 1 /** \file algorithm.cpp ******************************************************
anning865 0:82a90765baa2 2 *
anning865 0:82a90765baa2 3 * Project: MAXREFDES117#
anning865 0:82a90765baa2 4 * Filename: algorithm.cpp
anning865 0:82a90765baa2 5 * Description: This module calculates the heart rate/SpO2 level
anning865 0:82a90765baa2 6 *
anning865 0:82a90765baa2 7 *
anning865 0:82a90765baa2 8 * --------------------------------------------------------------------
anning865 0:82a90765baa2 9 *
anning865 0:82a90765baa2 10 * This code follows the following naming conventions:
anning865 0:82a90765baa2 11 *
anning865 0:82a90765baa2 12 * char ch_pmod_value
anning865 0:82a90765baa2 13 * char (array) s_pmod_s_string[16]
anning865 0:82a90765baa2 14 * float f_pmod_value
anning865 0:82a90765baa2 15 * int32_t n_pmod_value
anning865 0:82a90765baa2 16 * int32_t (array) an_pmod_value[16]
anning865 0:82a90765baa2 17 * int16_t w_pmod_value
anning865 0:82a90765baa2 18 * int16_t (array) aw_pmod_value[16]
anning865 0:82a90765baa2 19 * uint16_t uw_pmod_value
anning865 0:82a90765baa2 20 * uint16_t (array) auw_pmod_value[16]
anning865 0:82a90765baa2 21 * uint8_t uch_pmod_value
anning865 0:82a90765baa2 22 * uint8_t (array) auch_pmod_buffer[16]
anning865 0:82a90765baa2 23 * uint32_t un_pmod_value
anning865 0:82a90765baa2 24 * int32_t * pn_pmod_value
anning865 0:82a90765baa2 25 *
anning865 0:82a90765baa2 26 * ------------------------------------------------------------------------- */
anning865 0:82a90765baa2 27 /*******************************************************************************
anning865 0:82a90765baa2 28 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
anning865 0:82a90765baa2 29 *
anning865 0:82a90765baa2 30 * Permission is hereby granted, free of charge, to any person obtaining a
anning865 0:82a90765baa2 31 * copy of this software and associated documentation files (the "Software"),
anning865 0:82a90765baa2 32 * to deal in the Software without restriction, including without limitation
anning865 0:82a90765baa2 33 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
anning865 0:82a90765baa2 34 * and/or sell copies of the Software, and to permit persons to whom the
anning865 0:82a90765baa2 35 * Software is furnished to do so, subject to the following conditions:
anning865 0:82a90765baa2 36 *
anning865 0:82a90765baa2 37 * The above copyright notice and this permission notice shall be included
anning865 0:82a90765baa2 38 * in all copies or substantial portions of the Software.
anning865 0:82a90765baa2 39 *
anning865 0:82a90765baa2 40 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
anning865 0:82a90765baa2 41 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
anning865 0:82a90765baa2 42 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
anning865 0:82a90765baa2 43 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
anning865 0:82a90765baa2 44 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
anning865 0:82a90765baa2 45 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
anning865 0:82a90765baa2 46 * OTHER DEALINGS IN THE SOFTWARE.
anning865 0:82a90765baa2 47 *
anning865 0:82a90765baa2 48 * Except as contained in this notice, the name of Maxim Integrated
anning865 0:82a90765baa2 49 * Products, Inc. shall not be used except as stated in the Maxim Integrated
anning865 0:82a90765baa2 50 * Products, Inc. Branding Policy.
anning865 0:82a90765baa2 51 *
anning865 0:82a90765baa2 52 * The mere transfer of this software does not imply any licenses
anning865 0:82a90765baa2 53 * of trade secrets, proprietary technology, copyrights, patents,
anning865 0:82a90765baa2 54 * trademarks, maskwork rights, or any other form of intellectual
anning865 0:82a90765baa2 55 * property whatsoever. Maxim Integrated Products, Inc. retains all
anning865 0:82a90765baa2 56 * ownership rights.
anning865 0:82a90765baa2 57 *******************************************************************************
anning865 0:82a90765baa2 58 */
anning865 0:82a90765baa2 59 #include "algorithm.h"
anning865 0:82a90765baa2 60 #include "mbed.h"
anning865 0:82a90765baa2 61
anning865 0:82a90765baa2 62 void maxim_heart_rate_and_oxygen_saturation(uint32_t *pun_ir_buffer, int32_t n_ir_buffer_length, uint32_t *pun_red_buffer, int32_t *pn_spo2, int8_t *pch_spo2_valid,
anning865 0:82a90765baa2 63 int32_t *pn_heart_rate, int8_t *pch_hr_valid)
anning865 0:82a90765baa2 64 /**
anning865 0:82a90765baa2 65 * \brief Calculate the heart rate and SpO2 level
anning865 0:82a90765baa2 66 * \par Details
anning865 0:82a90765baa2 67 * By detecting peaks of PPG cycle and corresponding AC/DC of red/infra-red signal, the ratio for the SPO2 is computed.
anning865 0:82a90765baa2 68 * Since this algorithm is aiming for Arm M0/M3. formaula for SPO2 did not achieve the accuracy due to register overflow.
anning865 0:82a90765baa2 69 * Thus, accurate SPO2 is precalculated and save longo uch_spo2_table[] per each ratio.
anning865 0:82a90765baa2 70 *
anning865 0:82a90765baa2 71 * \param[in] *pun_ir_buffer - IR sensor data buffer
anning865 0:82a90765baa2 72 * \param[in] n_ir_buffer_length - IR sensor data buffer length
anning865 0:82a90765baa2 73 * \param[in] *pun_red_buffer - Red sensor data buffer
anning865 0:82a90765baa2 74 * \param[out] *pn_spo2 - Calculated SpO2 value
anning865 0:82a90765baa2 75 * \param[out] *pch_spo2_valid - 1 if the calculated SpO2 value is valid
anning865 0:82a90765baa2 76 * \param[out] *pn_heart_rate - Calculated heart rate value
anning865 0:82a90765baa2 77 * \param[out] *pch_hr_valid - 1 if the calculated heart rate value is valid
anning865 0:82a90765baa2 78 *
anning865 0:82a90765baa2 79 * \retval None
anning865 0:82a90765baa2 80 */
anning865 0:82a90765baa2 81 {
anning865 0:82a90765baa2 82 uint32_t un_ir_mean ,un_only_once ;
anning865 0:82a90765baa2 83 int32_t k ,n_i_ratio_count;
anning865 0:82a90765baa2 84 int32_t i, s, m, n_exact_ir_valley_locs_count ,n_middle_idx;
anning865 0:82a90765baa2 85 int32_t n_th1, n_npks,n_c_min;
anning865 0:82a90765baa2 86 int32_t an_ir_valley_locs[15] ;
anning865 0:82a90765baa2 87 int32_t an_exact_ir_valley_locs[15] ;
anning865 0:82a90765baa2 88 int32_t an_dx_peak_locs[15] ;
anning865 0:82a90765baa2 89 int32_t n_peak_interval_sum;
anning865 0:82a90765baa2 90
anning865 0:82a90765baa2 91 int32_t n_y_ac, n_x_ac;
anning865 0:82a90765baa2 92 int32_t n_spo2_calc;
anning865 0:82a90765baa2 93 int32_t n_y_dc_max, n_x_dc_max;
anning865 0:82a90765baa2 94 int32_t n_y_dc_max_idx, n_x_dc_max_idx;
anning865 0:82a90765baa2 95 int32_t an_ratio[5],n_ratio_average;
anning865 0:82a90765baa2 96 int32_t n_nume, n_denom ;
anning865 0:82a90765baa2 97 // remove DC of ir signal
anning865 0:82a90765baa2 98 un_ir_mean =0;
anning865 0:82a90765baa2 99 for (k=0 ; k<n_ir_buffer_length ; k++ ) un_ir_mean += pun_ir_buffer[k] ;
anning865 0:82a90765baa2 100 un_ir_mean =un_ir_mean/n_ir_buffer_length ;
anning865 0:82a90765baa2 101 for (k=0 ; k<n_ir_buffer_length ; k++ ) an_x[k] = pun_ir_buffer[k] - un_ir_mean ;
anning865 0:82a90765baa2 102
anning865 0:82a90765baa2 103 // 4 pt Moving Average
anning865 0:82a90765baa2 104 for(k=0; k< BUFFER_SIZE-MA4_SIZE; k++){
anning865 0:82a90765baa2 105 n_denom= ( an_x[k]+an_x[k+1]+ an_x[k+2]+ an_x[k+3]);
anning865 0:82a90765baa2 106 an_x[k]= n_denom/(int32_t)4;
anning865 0:82a90765baa2 107 }
anning865 0:82a90765baa2 108
anning865 0:82a90765baa2 109 // get difference of smoothed IR signal
anning865 0:82a90765baa2 110
anning865 0:82a90765baa2 111 for( k=0; k<BUFFER_SIZE-MA4_SIZE-1; k++)
anning865 0:82a90765baa2 112 an_dx[k]= (an_x[k+1]- an_x[k]);
anning865 0:82a90765baa2 113
anning865 0:82a90765baa2 114 // 2-pt Moving Average to an_dx
anning865 0:82a90765baa2 115 for(k=0; k< BUFFER_SIZE-MA4_SIZE-2; k++){
anning865 0:82a90765baa2 116 an_dx[k] = ( an_dx[k]+an_dx[k+1])/2 ;
anning865 0:82a90765baa2 117 }
anning865 0:82a90765baa2 118
anning865 0:82a90765baa2 119 // hamming window
anning865 0:82a90765baa2 120 // flip wave form so that we can detect valley with peak detector
anning865 0:82a90765baa2 121 for ( i=0 ; i<BUFFER_SIZE-HAMMING_SIZE-MA4_SIZE-2 ;i++){
anning865 0:82a90765baa2 122 s= 0;
anning865 0:82a90765baa2 123 for( k=i; k<i+ HAMMING_SIZE ;k++){
anning865 0:82a90765baa2 124 s -= an_dx[k] *auw_hamm[k-i] ;
anning865 0:82a90765baa2 125 }
anning865 0:82a90765baa2 126 an_dx[i]= s/ (int32_t)1146; // divide by sum of auw_hamm
anning865 0:82a90765baa2 127 }
anning865 0:82a90765baa2 128
anning865 0:82a90765baa2 129
anning865 0:82a90765baa2 130 n_th1=0; // threshold calculation
anning865 0:82a90765baa2 131 for ( k=0 ; k<BUFFER_SIZE-HAMMING_SIZE ;k++){
anning865 0:82a90765baa2 132 n_th1 += ((an_dx[k]>0)? an_dx[k] : ((int32_t)0-an_dx[k])) ;
anning865 0:82a90765baa2 133 }
anning865 0:82a90765baa2 134 n_th1= n_th1/ ( BUFFER_SIZE-HAMMING_SIZE);
anning865 0:82a90765baa2 135 // peak location is acutally index for sharpest location of raw signal since we flipped the signal
anning865 0:82a90765baa2 136 maxim_find_peaks( an_dx_peak_locs, &n_npks, an_dx, BUFFER_SIZE-HAMMING_SIZE, n_th1, 8, 5 );//peak_height, peak_distance, max_num_peaks
anning865 0:82a90765baa2 137
anning865 0:82a90765baa2 138 n_peak_interval_sum =0;
anning865 0:82a90765baa2 139 if (n_npks>=2){
anning865 0:82a90765baa2 140 for (k=1; k<n_npks; k++)
anning865 0:82a90765baa2 141 n_peak_interval_sum += (an_dx_peak_locs[k]-an_dx_peak_locs[k -1]);
anning865 0:82a90765baa2 142 n_peak_interval_sum=n_peak_interval_sum/(n_npks-1);
anning865 0:82a90765baa2 143 *pn_heart_rate=(int32_t)(6000/n_peak_interval_sum);// beats per minutes
anning865 0:82a90765baa2 144 *pch_hr_valid = 1;
anning865 0:82a90765baa2 145 }
anning865 0:82a90765baa2 146 else {
anning865 0:82a90765baa2 147 *pn_heart_rate = -999;
anning865 0:82a90765baa2 148 *pch_hr_valid = 0;
anning865 0:82a90765baa2 149 }
anning865 0:82a90765baa2 150
anning865 0:82a90765baa2 151 for ( k=0 ; k<n_npks ;k++)
anning865 0:82a90765baa2 152 an_ir_valley_locs[k]=an_dx_peak_locs[k]+HAMMING_SIZE/2;
anning865 0:82a90765baa2 153
anning865 0:82a90765baa2 154
anning865 0:82a90765baa2 155 // raw value : RED(=y) and IR(=X)
anning865 0:82a90765baa2 156 // we need to assess DC and AC value of ir and red PPG.
anning865 0:82a90765baa2 157 for (k=0 ; k<n_ir_buffer_length ; k++ ) {
anning865 0:82a90765baa2 158 an_x[k] = pun_ir_buffer[k] ;
anning865 0:82a90765baa2 159 an_y[k] = pun_red_buffer[k] ;
anning865 0:82a90765baa2 160 }
anning865 0:82a90765baa2 161
anning865 0:82a90765baa2 162 // find precise min near an_ir_valley_locs
anning865 0:82a90765baa2 163 n_exact_ir_valley_locs_count =0;
anning865 0:82a90765baa2 164 for(k=0 ; k<n_npks ;k++){
anning865 0:82a90765baa2 165 un_only_once =1;
anning865 0:82a90765baa2 166 m=an_ir_valley_locs[k];
anning865 0:82a90765baa2 167 n_c_min= 16777216;//2^24;
anning865 0:82a90765baa2 168 if (m+5 < BUFFER_SIZE-HAMMING_SIZE && m-5 >0){
anning865 0:82a90765baa2 169 for(i= m-5;i<m+5; i++)
anning865 0:82a90765baa2 170 if (an_x[i]<n_c_min){
anning865 0:82a90765baa2 171 if (un_only_once >0){
anning865 0:82a90765baa2 172 un_only_once =0;
anning865 0:82a90765baa2 173 }
anning865 0:82a90765baa2 174 n_c_min= an_x[i] ;
anning865 0:82a90765baa2 175 an_exact_ir_valley_locs[k]=i;
anning865 0:82a90765baa2 176 }
anning865 0:82a90765baa2 177 if (un_only_once ==0)
anning865 0:82a90765baa2 178 n_exact_ir_valley_locs_count ++ ;
anning865 0:82a90765baa2 179 }
anning865 0:82a90765baa2 180 }
anning865 0:82a90765baa2 181 if (n_exact_ir_valley_locs_count <2 ){
anning865 0:82a90765baa2 182 *pn_spo2 = -999 ; // do not use SPO2 since signal ratio is out of range
anning865 0:82a90765baa2 183 *pch_spo2_valid = 0;
anning865 0:82a90765baa2 184 return;
anning865 0:82a90765baa2 185 }
anning865 0:82a90765baa2 186 // 4 pt MA
anning865 0:82a90765baa2 187 for(k=0; k< BUFFER_SIZE-MA4_SIZE; k++){
anning865 0:82a90765baa2 188 an_x[k]=( an_x[k]+an_x[k+1]+ an_x[k+2]+ an_x[k+3])/(int32_t)4;
anning865 0:82a90765baa2 189 an_y[k]=( an_y[k]+an_y[k+1]+ an_y[k+2]+ an_y[k+3])/(int32_t)4;
anning865 0:82a90765baa2 190 }
anning865 0:82a90765baa2 191
anning865 0:82a90765baa2 192 //using an_exact_ir_valley_locs , find ir-red DC andir-red AC for SPO2 calibration ratio
anning865 0:82a90765baa2 193 //finding AC/DC maximum of raw ir * red between two valley locations
anning865 0:82a90765baa2 194 n_ratio_average =0;
anning865 0:82a90765baa2 195 n_i_ratio_count =0;
anning865 0:82a90765baa2 196
anning865 0:82a90765baa2 197 for(k=0; k< 5; k++) an_ratio[k]=0;
anning865 0:82a90765baa2 198 for (k=0; k< n_exact_ir_valley_locs_count; k++){
anning865 0:82a90765baa2 199 if (an_exact_ir_valley_locs[k] > BUFFER_SIZE ){
anning865 0:82a90765baa2 200 *pn_spo2 = -999 ; // do not use SPO2 since valley loc is out of range
anning865 0:82a90765baa2 201 *pch_spo2_valid = 0;
anning865 0:82a90765baa2 202 return;
anning865 0:82a90765baa2 203 }
anning865 0:82a90765baa2 204 }
anning865 0:82a90765baa2 205 // find max between two valley locations
anning865 0:82a90765baa2 206 // and use ratio betwen AC compoent of Ir & Red and DC compoent of Ir & Red for SPO2
anning865 0:82a90765baa2 207
anning865 0:82a90765baa2 208 for (k=0; k< n_exact_ir_valley_locs_count-1; k++){
anning865 0:82a90765baa2 209 n_y_dc_max= -16777216 ;
anning865 0:82a90765baa2 210 n_x_dc_max= - 16777216;
anning865 0:82a90765baa2 211 if (an_exact_ir_valley_locs[k+1]-an_exact_ir_valley_locs[k] >10){
anning865 0:82a90765baa2 212 for (i=an_exact_ir_valley_locs[k]; i< an_exact_ir_valley_locs[k+1]; i++){
anning865 0:82a90765baa2 213 if (an_x[i]> n_x_dc_max) {n_x_dc_max =an_x[i];n_x_dc_max_idx =i; }
anning865 0:82a90765baa2 214 if (an_y[i]> n_y_dc_max) {n_y_dc_max =an_y[i];n_y_dc_max_idx=i;}
anning865 0:82a90765baa2 215 }
anning865 0:82a90765baa2 216 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
anning865 0:82a90765baa2 217 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]) ;
anning865 0:82a90765baa2 218
anning865 0:82a90765baa2 219
anning865 0:82a90765baa2 220 n_y_ac= an_y[n_y_dc_max_idx] - n_y_ac; // subracting linear DC compoenents from raw
anning865 0:82a90765baa2 221 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
anning865 0:82a90765baa2 222 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]);
anning865 0:82a90765baa2 223 n_x_ac= an_x[n_y_dc_max_idx] - n_x_ac; // subracting linear DC compoenents from raw
anning865 0:82a90765baa2 224 n_nume=( n_y_ac *n_x_dc_max)>>7 ; //prepare X100 to preserve floating value
anning865 0:82a90765baa2 225 n_denom= ( n_x_ac *n_y_dc_max)>>7;
anning865 0:82a90765baa2 226 if (n_denom>0 && n_i_ratio_count <5 && n_nume != 0)
anning865 0:82a90765baa2 227 {
anning865 0:82a90765baa2 228 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) ;
anning865 0:82a90765baa2 229 n_i_ratio_count++;
anning865 0:82a90765baa2 230 }
anning865 0:82a90765baa2 231 }
anning865 0:82a90765baa2 232 }
anning865 0:82a90765baa2 233
anning865 0:82a90765baa2 234 maxim_sort_ascend(an_ratio, n_i_ratio_count);
anning865 0:82a90765baa2 235 n_middle_idx= n_i_ratio_count/2;
anning865 0:82a90765baa2 236
anning865 0:82a90765baa2 237 if (n_middle_idx >1)
anning865 0:82a90765baa2 238 n_ratio_average =( an_ratio[n_middle_idx-1] +an_ratio[n_middle_idx])/2; // use median
anning865 0:82a90765baa2 239 else
anning865 0:82a90765baa2 240 n_ratio_average = an_ratio[n_middle_idx ];
anning865 0:82a90765baa2 241
anning865 0:82a90765baa2 242 if( n_ratio_average>2 && n_ratio_average <184){
anning865 0:82a90765baa2 243 n_spo2_calc= uch_spo2_table[n_ratio_average] ;
anning865 0:82a90765baa2 244 *pn_spo2 = n_spo2_calc ;
anning865 0:82a90765baa2 245 *pch_spo2_valid = 1;// float_SPO2 = -45.060*n_ratio_average* n_ratio_average/10000 + 30.354 *n_ratio_average/100 + 94.845 ; // for comparison with table
anning865 0:82a90765baa2 246 }
anning865 0:82a90765baa2 247 else{
anning865 0:82a90765baa2 248 *pn_spo2 = -999 ; // do not use SPO2 since signal ratio is out of range
anning865 0:82a90765baa2 249 *pch_spo2_valid = 0;
anning865 0:82a90765baa2 250 }
anning865 0:82a90765baa2 251 }
anning865 0:82a90765baa2 252
anning865 0:82a90765baa2 253
anning865 0:82a90765baa2 254 void maxim_find_peaks(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_size, int32_t n_min_height, int32_t n_min_distance, int32_t n_max_num)
anning865 0:82a90765baa2 255 /**
anning865 0:82a90765baa2 256 * \brief Find peaks
anning865 0:82a90765baa2 257 * \par Details
anning865 0:82a90765baa2 258 * Find at most MAX_NUM peaks above MIN_HEIGHT separated by at least MIN_DISTANCE
anning865 0:82a90765baa2 259 *
anning865 0:82a90765baa2 260 * \retval None
anning865 0:82a90765baa2 261 */
anning865 0:82a90765baa2 262 {
anning865 0:82a90765baa2 263 maxim_peaks_above_min_height( pn_locs, pn_npks, pn_x, n_size, n_min_height );
anning865 0:82a90765baa2 264 maxim_remove_close_peaks( pn_locs, pn_npks, pn_x, n_min_distance );
anning865 0:82a90765baa2 265 *pn_npks = min( *pn_npks, n_max_num );
anning865 0:82a90765baa2 266 }
anning865 0:82a90765baa2 267
anning865 0:82a90765baa2 268 void maxim_peaks_above_min_height(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_size, int32_t n_min_height)
anning865 0:82a90765baa2 269 /**
anning865 0:82a90765baa2 270 * \brief Find peaks above n_min_height
anning865 0:82a90765baa2 271 * \par Details
anning865 0:82a90765baa2 272 * Find all peaks above MIN_HEIGHT
anning865 0:82a90765baa2 273 *
anning865 0:82a90765baa2 274 * \retval None
anning865 0:82a90765baa2 275 */
anning865 0:82a90765baa2 276 {
anning865 0:82a90765baa2 277 int32_t i = 1, n_width;
anning865 0:82a90765baa2 278 *pn_npks = 0;
anning865 0:82a90765baa2 279
anning865 0:82a90765baa2 280 while (i < n_size-1){
anning865 0:82a90765baa2 281 if (pn_x[i] > n_min_height && pn_x[i] > pn_x[i-1]){ // find left edge of potential peaks
anning865 0:82a90765baa2 282 n_width = 1;
anning865 0:82a90765baa2 283 while (i+n_width < n_size && pn_x[i] == pn_x[i+n_width]) // find flat peaks
anning865 0:82a90765baa2 284 n_width++;
anning865 0:82a90765baa2 285 if (pn_x[i] > pn_x[i+n_width] && (*pn_npks) < 15 ){ // find right edge of peaks
anning865 0:82a90765baa2 286 pn_locs[(*pn_npks)++] = i;
anning865 0:82a90765baa2 287 // for flat peaks, peak location is left edge
anning865 0:82a90765baa2 288 i += n_width+1;
anning865 0:82a90765baa2 289 }
anning865 0:82a90765baa2 290 else
anning865 0:82a90765baa2 291 i += n_width;
anning865 0:82a90765baa2 292 }
anning865 0:82a90765baa2 293 else
anning865 0:82a90765baa2 294 i++;
anning865 0:82a90765baa2 295 }
anning865 0:82a90765baa2 296 }
anning865 0:82a90765baa2 297
anning865 0:82a90765baa2 298
anning865 0:82a90765baa2 299 void maxim_remove_close_peaks(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_min_distance)
anning865 0:82a90765baa2 300 /**
anning865 0:82a90765baa2 301 * \brief Remove peaks
anning865 0:82a90765baa2 302 * \par Details
anning865 0:82a90765baa2 303 * Remove peaks separated by less than MIN_DISTANCE
anning865 0:82a90765baa2 304 *
anning865 0:82a90765baa2 305 * \retval None
anning865 0:82a90765baa2 306 */
anning865 0:82a90765baa2 307 {
anning865 0:82a90765baa2 308
anning865 0:82a90765baa2 309 int32_t i, j, n_old_npks, n_dist;
anning865 0:82a90765baa2 310
anning865 0:82a90765baa2 311 /* Order peaks from large to small */
anning865 0:82a90765baa2 312 maxim_sort_indices_descend( pn_x, pn_locs, *pn_npks );
anning865 0:82a90765baa2 313
anning865 0:82a90765baa2 314 for ( i = -1; i < *pn_npks; i++ ){
anning865 0:82a90765baa2 315 n_old_npks = *pn_npks;
anning865 0:82a90765baa2 316 *pn_npks = i+1;
anning865 0:82a90765baa2 317 for ( j = i+1; j < n_old_npks; j++ ){
anning865 0:82a90765baa2 318 n_dist = pn_locs[j] - ( i == -1 ? -1 : pn_locs[i] ); // lag-zero peak of autocorr is at index -1
anning865 0:82a90765baa2 319 if ( n_dist > n_min_distance || n_dist < -n_min_distance )
anning865 0:82a90765baa2 320 pn_locs[(*pn_npks)++] = pn_locs[j];
anning865 0:82a90765baa2 321 }
anning865 0:82a90765baa2 322 }
anning865 0:82a90765baa2 323
anning865 0:82a90765baa2 324 // Resort indices longo ascending order
anning865 0:82a90765baa2 325 maxim_sort_ascend( pn_locs, *pn_npks );
anning865 0:82a90765baa2 326 }
anning865 0:82a90765baa2 327
anning865 0:82a90765baa2 328 void maxim_sort_ascend(int32_t *pn_x,int32_t n_size)
anning865 0:82a90765baa2 329 /**
anning865 0:82a90765baa2 330 * \brief Sort array
anning865 0:82a90765baa2 331 * \par Details
anning865 0:82a90765baa2 332 * Sort array in ascending order (insertion sort algorithm)
anning865 0:82a90765baa2 333 *
anning865 0:82a90765baa2 334 * \retval None
anning865 0:82a90765baa2 335 */
anning865 0:82a90765baa2 336 {
anning865 0:82a90765baa2 337 int32_t i, j, n_temp;
anning865 0:82a90765baa2 338 for (i = 1; i < n_size; i++) {
anning865 0:82a90765baa2 339 n_temp = pn_x[i];
anning865 0:82a90765baa2 340 for (j = i; j > 0 && n_temp < pn_x[j-1]; j--)
anning865 0:82a90765baa2 341 pn_x[j] = pn_x[j-1];
anning865 0:82a90765baa2 342 pn_x[j] = n_temp;
anning865 0:82a90765baa2 343 }
anning865 0:82a90765baa2 344 }
anning865 0:82a90765baa2 345
anning865 0:82a90765baa2 346 void maxim_sort_indices_descend(int32_t *pn_x, int32_t *pn_indx, int32_t n_size)
anning865 0:82a90765baa2 347 /**
anning865 0:82a90765baa2 348 * \brief Sort indices
anning865 0:82a90765baa2 349 * \par Details
anning865 0:82a90765baa2 350 * Sort indices according to descending order (insertion sort algorithm)
anning865 0:82a90765baa2 351 *
anning865 0:82a90765baa2 352 * \retval None
anning865 0:82a90765baa2 353 */
anning865 0:82a90765baa2 354 {
anning865 0:82a90765baa2 355 int32_t i, j, n_temp;
anning865 0:82a90765baa2 356 for (i = 1; i < n_size; i++) {
anning865 0:82a90765baa2 357 n_temp = pn_indx[i];
anning865 0:82a90765baa2 358 for (j = i; j > 0 && pn_x[n_temp] > pn_x[pn_indx[j-1]]; j--)
anning865 0:82a90765baa2 359 pn_indx[j] = pn_indx[j-1];
anning865 0:82a90765baa2 360 pn_indx[j] = n_temp;
anning865 0:82a90765baa2 361 }
anning865 0:82a90765baa2 362 }
anning865 0:82a90765baa2 363