ENSMM / Mbed 2 deprecated MAX30102_Meuhve_Sensor

Test program for a Max30102 heartrate sensor on a STM32L476RG specific board ENSMM

Dependencies:   mbed

These two pictures show how to connect the Mheuve Sensor to the ST-Link debugger (don't forget to disable ST-link jumpers and JP5 on the board! ):

https://os.mbed.com/media/uploads/jimbaud/1611739514454.jpghttps://os.mbed.com/media/uploads/jimbaud/1611739514453.jpg

These two pictures show how to connect the Mheuve Sensor TX RX to the ST-Link debugger (don't forget to cross TX and RX, it means Mheuve sensor TX on ST-Link RX and ST-Link TX on Mheuve sensor RX ):

https://os.mbed.com/media/uploads/jimbaud/1611739514450.jpg https://os.mbed.com/media/uploads/jimbaud/1611739514452.jpg

The Mheuve sensor board needs to be powered by an external battery.

The result appears on the terminal, speed config is 115200 bds.

https://os.mbed.com/media/uploads/jimbaud/terminal.jpg

algorithm/algorithm.cpp@2:560e76e77544, 2016-04-21 (annotated)

Committer:
MaximGordon
Date:
Thu Apr 21 18:25:34 2016 +0000
Revision:
2:560e76e77544
Parent:
1:e88f22c6c1b0
Child:
3:7c0fb55eb3ff
updated variable names

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MaximGordon 1:e88f22c6c1b0 1 /** \file algorithm.cpp ******************************************************
MaximGordon 0:346a7fa07998 2 *
MaximGordon 0:346a7fa07998 3 * Project: MAXREFDES117#
MaximGordon 1:e88f22c6c1b0 4 * Filename: algorithm.cpp
MaximGordon 0:346a7fa07998 5 * Description: This module calculates the heart rate/SpO2 level
MaximGordon 0:346a7fa07998 6 *
MaximGordon 0:346a7fa07998 7 * Revision History:
MaximGordon 0:346a7fa07998 8 *\n 1-18-2016 Rev 01.00 SK Initial release.
MaximGordon 0:346a7fa07998 9 *\n
MaximGordon 0:346a7fa07998 10 *
MaximGordon 0:346a7fa07998 11 * --------------------------------------------------------------------
MaximGordon 0:346a7fa07998 12 *
MaximGordon 0:346a7fa07998 13 * This code follows the following naming conventions:
MaximGordon 0:346a7fa07998 14 *
MaximGordon 0:346a7fa07998 15 *\n char ch_pmod_value
MaximGordon 0:346a7fa07998 16 *\n char (array) s_pmod_s_string[16]
MaximGordon 0:346a7fa07998 17 *\n float f_pmod_value
MaximGordon 0:346a7fa07998 18 *\n int32_t n_pmod_value
MaximGordon 0:346a7fa07998 19 *\n int32_t (array) an_pmod_value[16]
MaximGordon 0:346a7fa07998 20 *\n int16_t w_pmod_value
MaximGordon 0:346a7fa07998 21 *\n int16_t (array) aw_pmod_value[16]
MaximGordon 0:346a7fa07998 22 *\n uint16_t uw_pmod_value
MaximGordon 0:346a7fa07998 23 *\n uint16_t (array) auw_pmod_value[16]
MaximGordon 0:346a7fa07998 24 *\n uint8_t uch_pmod_value
MaximGordon 0:346a7fa07998 25 *\n uint8_t (array) auch_pmod_buffer[16]
MaximGordon 0:346a7fa07998 26 *\n uint32_t un_pmod_value
MaximGordon 0:346a7fa07998 27 *\n int32_t * pn_pmod_value
MaximGordon 0:346a7fa07998 28 *
MaximGordon 0:346a7fa07998 29 * ------------------------------------------------------------------------- */
MaximGordon 0:346a7fa07998 30 /*******************************************************************************
MaximGordon 0:346a7fa07998 31 * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
MaximGordon 0:346a7fa07998 32 *
MaximGordon 0:346a7fa07998 33 * Permission is hereby granted, free of charge, to any person obtaining a
MaximGordon 0:346a7fa07998 34 * copy of this software and associated documentation files (the "Software"),
MaximGordon 0:346a7fa07998 35 * to deal in the Software without restriction, including without limitation
MaximGordon 0:346a7fa07998 36 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
MaximGordon 0:346a7fa07998 37 * and/or sell copies of the Software, and to permit persons to whom the
MaximGordon 0:346a7fa07998 38 * Software is furnished to do so, subject to the following conditions:
MaximGordon 0:346a7fa07998 39 *
MaximGordon 0:346a7fa07998 40 * The above copyright notice and this permission notice shall be included
MaximGordon 0:346a7fa07998 41 * in all copies or substantial portions of the Software.
MaximGordon 0:346a7fa07998 42 *
MaximGordon 0:346a7fa07998 43 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
MaximGordon 0:346a7fa07998 44 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MaximGordon 0:346a7fa07998 45 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
MaximGordon 0:346a7fa07998 46 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
MaximGordon 0:346a7fa07998 47 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
MaximGordon 0:346a7fa07998 48 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
MaximGordon 0:346a7fa07998 49 * OTHER DEALINGS IN THE SOFTWARE.
MaximGordon 0:346a7fa07998 50 *
MaximGordon 0:346a7fa07998 51 * Except as contained in this notice, the name of Maxim Integrated
MaximGordon 0:346a7fa07998 52 * Products, Inc. shall not be used except as stated in the Maxim Integrated
MaximGordon 0:346a7fa07998 53 * Products, Inc. Branding Policy.
MaximGordon 0:346a7fa07998 54 *
MaximGordon 0:346a7fa07998 55 * The mere transfer of this software does not imply any licenses
MaximGordon 0:346a7fa07998 56 * of trade secrets, proprietary technology, copyrights, patents,
MaximGordon 0:346a7fa07998 57 * trademarks, maskwork rights, or any other form of intellectual
MaximGordon 0:346a7fa07998 58 * property whatsoever. Maxim Integrated Products, Inc. retains all
MaximGordon 0:346a7fa07998 59 * ownership rights.
MaximGordon 0:346a7fa07998 60 *******************************************************************************
MaximGordon 0:346a7fa07998 61 */
MaximGordon 0:346a7fa07998 62 #include "algorithm.h"
MaximGordon 0:346a7fa07998 63 #include "mbed.h"
MaximGordon 0:346a7fa07998 64
MaximGordon 0:346a7fa07998 65 void maxim_heart_rate_and_oxygen_saturation(uint32_t *un_ir_buffer , int32_t n_ir_buffer_length, uint32_t *un_red_buffer , int32_t *n_spo2, int8_t *ch_spo2_valid ,
MaximGordon 0:346a7fa07998 66 int32_t *n_heart_rate , int8_t *ch_hr_valid)
MaximGordon 0:346a7fa07998 67 /**
MaximGordon 0:346a7fa07998 68 * \brief Calculate the heart rate and SpO2 level
MaximGordon 0:346a7fa07998 69 * \par Details
MaximGordon 0:346a7fa07998 70 * By detecting peaks of PPG cycle and corresponding AC/DC of red/infra-red signal, the ratio for the SPO2 is computed.
MaximGordon 0:346a7fa07998 71 * Since this algorithm is aiming for Arm M0/M3. formaula for SPO2 did not achieve the accuracy due to register overflow.
MaximGordon 0:346a7fa07998 72 * Thus, accurate SPO2 is precalculated and save longo uch_spo2_table[] per each ratio.
MaximGordon 0:346a7fa07998 73 *
MaximGordon 0:346a7fa07998 74 * \param[in] *un_ir_buffer - IR sensor data buffer
MaximGordon 0:346a7fa07998 75 * \param[in] n_ir_buffer_length - IR sensor data buffer length
MaximGordon 0:346a7fa07998 76 * \param[in] *un_red_buffer - Red sensor data buffer
MaximGordon 0:346a7fa07998 77 * \param[out] *n_spo2 - Calculated SpO2 value
MaximGordon 0:346a7fa07998 78 * \param[out] *ch_spo2_valid - 1 if the calculated SpO2 value is valid
MaximGordon 0:346a7fa07998 79 * \param[out] *n_heart_rate - Calculated heart rate value
MaximGordon 0:346a7fa07998 80 * \param[out] *ch_hr_valid - 1 if the calculated heart rate value is valid
MaximGordon 0:346a7fa07998 81 *
MaximGordon 0:346a7fa07998 82 * \retval None
MaximGordon 0:346a7fa07998 83 */
MaximGordon 0:346a7fa07998 84 {
MaximGordon 0:346a7fa07998 85
MaximGordon 0:346a7fa07998 86
MaximGordon 2:560e76e77544 87 uint32_t un_ir_mean ,un_only_once ;
MaximGordon 2:560e76e77544 88 int32_t k ,n_i_ratio_count;
MaximGordon 2:560e76e77544 89 int32_t i,s ,m, n_exact_ir_valley_locs_count ,n_middle_idx;
MaximGordon 2:560e76e77544 90 int32_t n_th1, n_npks,n_c_min;
MaximGordon 2:560e76e77544 91 int32_t n_ir_valley_locs[15] ;
MaximGordon 2:560e76e77544 92 int32_t n_exact_ir_valley_locs[15] ;
MaximGordon 2:560e76e77544 93 int32_t n_dx_peak_locs[15] ;
MaximGordon 2:560e76e77544 94 int32_t n_peak_interval_sum;
MaximGordon 0:346a7fa07998 95
MaximGordon 2:560e76e77544 96 int32_t n_y_ac, n_x_ac;
MaximGordon 2:560e76e77544 97 int32_t n_spo2_calc;
MaximGordon 2:560e76e77544 98 int32_t n_y_dc_max, n_x_dc_max;
MaximGordon 2:560e76e77544 99 int32_t n_y_dc_max_idx, n_x_dc_max_idx;
MaximGordon 2:560e76e77544 100 int32_t n_ratio[5],n_ratio_average;
MaximGordon 2:560e76e77544 101 int32_t n_nume, n_denom ;
MaximGordon 0:346a7fa07998 102 // remove DC of ir signal
MaximGordon 2:560e76e77544 103 un_ir_mean =0;
MaximGordon 2:560e76e77544 104 for (k=0 ; k<n_ir_buffer_length ; k++ ) un_ir_mean += un_ir_buffer[k] ;
MaximGordon 2:560e76e77544 105 un_ir_mean =un_ir_mean/n_ir_buffer_length ;
MaximGordon 2:560e76e77544 106 for (k=0 ; k<n_ir_buffer_length ; k++ ) n_x[k] = un_ir_buffer[k] - un_ir_mean ;
MaximGordon 0:346a7fa07998 107
MaximGordon 0:346a7fa07998 108 // 4 pt Moving Average
MaximGordon 0:346a7fa07998 109 for(k=0; k< BUFFER_SIZE-MA4_SIZE; k++){
MaximGordon 2:560e76e77544 110 n_denom= ( n_x[k]+n_x[k+1]+ n_x[k+2]+ n_x[k+3]);
MaximGordon 2:560e76e77544 111 n_x[k]= n_denom/(int32_t)4;
MaximGordon 0:346a7fa07998 112 }
MaximGordon 0:346a7fa07998 113
MaximGordon 0:346a7fa07998 114 // get difference of smoothed IR signal
MaximGordon 0:346a7fa07998 115
MaximGordon 0:346a7fa07998 116 for( k=0; k<BUFFER_SIZE-MA4_SIZE-1; k++)
MaximGordon 0:346a7fa07998 117 n_dx[k]= (n_x[k+1]- n_x[k]);
MaximGordon 0:346a7fa07998 118
MaximGordon 0:346a7fa07998 119 // 2-pt Moving Average to n_dx
MaximGordon 0:346a7fa07998 120 for(k=0; k< BUFFER_SIZE-MA4_SIZE-2; k++){
MaximGordon 0:346a7fa07998 121 n_dx[k] = ( n_dx[k]+n_dx[k+1])/2 ;
MaximGordon 0:346a7fa07998 122 }
MaximGordon 0:346a7fa07998 123
MaximGordon 0:346a7fa07998 124 // hamming window
MaximGordon 0:346a7fa07998 125 // flip wave form so that we can detect valley with peak detector
MaximGordon 0:346a7fa07998 126 for ( i=0 ; i<BUFFER_SIZE-HAMMING_SIZE-MA4_SIZE-2 ;i++){
MaximGordon 0:346a7fa07998 127 s= 0;
MaximGordon 0:346a7fa07998 128 for( k=i; k<i+ HAMMING_SIZE ;k++){
MaximGordon 0:346a7fa07998 129 s -= n_dx[k] *uw_hamm[k-i] ;
MaximGordon 0:346a7fa07998 130 }
MaximGordon 0:346a7fa07998 131 n_dx[i]= s/ (int32_t)1146; // divide by sum of uw_hamm
MaximGordon 0:346a7fa07998 132 }
MaximGordon 0:346a7fa07998 133
MaximGordon 0:346a7fa07998 134
MaximGordon 2:560e76e77544 135 n_th1=0; // threshold calculation
MaximGordon 0:346a7fa07998 136 for ( k=0 ; k<BUFFER_SIZE-HAMMING_SIZE ;k++){
MaximGordon 2:560e76e77544 137 n_th1 += ((n_dx[k]>0)? n_dx[k] : ((int32_t)0-n_dx[k])) ;
MaximGordon 0:346a7fa07998 138 }
MaximGordon 2:560e76e77544 139 n_th1= n_th1/ ( BUFFER_SIZE-HAMMING_SIZE);
MaximGordon 0:346a7fa07998 140 // peak location is acutally index for sharpest location of raw signal since we flipped the signal
MaximGordon 2:560e76e77544 141 maxim_find_peaks( n_dx_peak_locs, &n_npks, n_dx, BUFFER_SIZE-HAMMING_SIZE, n_th1, 8, 5 );//peak_height, peak_distance, max_num_peaks
MaximGordon 0:346a7fa07998 142
MaximGordon 2:560e76e77544 143 n_peak_interval_sum =0;
MaximGordon 0:346a7fa07998 144 if (n_npks>=2){
MaximGordon 0:346a7fa07998 145 for (k=1; k<n_npks; k++)
MaximGordon 2:560e76e77544 146 n_peak_interval_sum += (n_dx_peak_locs[k] -n_dx_peak_locs[k -1] ) ;
MaximGordon 2:560e76e77544 147 n_peak_interval_sum =n_peak_interval_sum/(n_npks-1);
MaximGordon 2:560e76e77544 148 *n_heart_rate =(int32_t)( 6000/ n_peak_interval_sum );// beats per minutes
MaximGordon 0:346a7fa07998 149 //prlongf(">>> *n_heart_rate= %d \n", *n_heart_rate) ;
MaximGordon 0:346a7fa07998 150 *ch_hr_valid = 1;
MaximGordon 0:346a7fa07998 151 }
MaximGordon 0:346a7fa07998 152 else {
MaximGordon 0:346a7fa07998 153 *n_heart_rate = -999;
MaximGordon 0:346a7fa07998 154 *ch_hr_valid = 0;
MaximGordon 0:346a7fa07998 155 }
MaximGordon 0:346a7fa07998 156
MaximGordon 0:346a7fa07998 157 for ( k=0 ; k<n_npks ;k++)
MaximGordon 2:560e76e77544 158 n_ir_valley_locs[k]= n_dx_peak_locs[k] +HAMMING_SIZE /2;
MaximGordon 0:346a7fa07998 159
MaximGordon 0:346a7fa07998 160
MaximGordon 0:346a7fa07998 161 // raw value : RED(=y) and IR(=X)
MaximGordon 0:346a7fa07998 162 // we need to assess DC and AC value of ir and red PPG.
MaximGordon 0:346a7fa07998 163 for (k=0 ; k<n_ir_buffer_length ; k++ ) {
MaximGordon 0:346a7fa07998 164 n_x[k] = un_ir_buffer[k] ;
MaximGordon 0:346a7fa07998 165 n_y[k] = un_red_buffer[k] ;
MaximGordon 0:346a7fa07998 166 }
MaximGordon 0:346a7fa07998 167
MaximGordon 2:560e76e77544 168 // find precise min near n_ir_valley_locs
MaximGordon 2:560e76e77544 169 n_exact_ir_valley_locs_count =0;
MaximGordon 0:346a7fa07998 170 for ( k=0 ; k<n_npks ;k++){
MaximGordon 2:560e76e77544 171 un_only_once =1;
MaximGordon 2:560e76e77544 172 m=n_ir_valley_locs[k];
MaximGordon 2:560e76e77544 173 n_c_min= 16777216;//2^24;
MaximGordon 0:346a7fa07998 174 if (m+5 < BUFFER_SIZE-HAMMING_SIZE && m-5 >0){
MaximGordon 0:346a7fa07998 175
MaximGordon 0:346a7fa07998 176 for(i= m-5;i<m+5; i++)
MaximGordon 2:560e76e77544 177 if (n_x[i]<n_c_min){
MaximGordon 2:560e76e77544 178 if (un_only_once >0){
MaximGordon 2:560e76e77544 179 un_only_once =0;
MaximGordon 0:346a7fa07998 180 }
MaximGordon 2:560e76e77544 181 n_c_min= n_x[i] ;
MaximGordon 2:560e76e77544 182 n_exact_ir_valley_locs[k]=i;
MaximGordon 0:346a7fa07998 183 }
MaximGordon 2:560e76e77544 184 if (un_only_once ==0) n_exact_ir_valley_locs_count ++ ;
MaximGordon 0:346a7fa07998 185 }
MaximGordon 0:346a7fa07998 186 }
MaximGordon 2:560e76e77544 187 if (n_exact_ir_valley_locs_count <2 ){
MaximGordon 0:346a7fa07998 188 *n_spo2 = -999 ; // do not use SPO2 since signal ratio is out of range
MaximGordon 0:346a7fa07998 189 *ch_spo2_valid = 0;
MaximGordon 0:346a7fa07998 190 return;
MaximGordon 0:346a7fa07998 191 }
MaximGordon 0:346a7fa07998 192 // 4 pt MA
MaximGordon 0:346a7fa07998 193 for(k=0; k< BUFFER_SIZE-MA4_SIZE; k++){
MaximGordon 0:346a7fa07998 194 n_x[k]=( n_x[k]+n_x[k+1]+ n_x[k+2]+ n_x[k+3])/(int32_t)4;
MaximGordon 0:346a7fa07998 195 n_y[k]=( n_y[k]+n_y[k+1]+ n_y[k+2]+ n_y[k+3])/(int32_t)4;
MaximGordon 0:346a7fa07998 196
MaximGordon 0:346a7fa07998 197 }
MaximGordon 0:346a7fa07998 198
MaximGordon 2:560e76e77544 199 //using n_exact_ir_valley_locs , find ir-red DC andir-red AC for SPO2 calibration ratio
MaximGordon 0:346a7fa07998 200 //finding AC/DC maximum of raw ir * red between two valley locations
MaximGordon 2:560e76e77544 201 n_ratio_average =0;
MaximGordon 2:560e76e77544 202 n_i_ratio_count = 0;
MaximGordon 0:346a7fa07998 203
MaximGordon 2:560e76e77544 204 for(k=0; k< 5; k++) n_ratio[k]=0;
MaximGordon 2:560e76e77544 205 for (k=0; k< n_exact_ir_valley_locs_count; k++){
MaximGordon 2:560e76e77544 206 if (n_exact_ir_valley_locs[k] > BUFFER_SIZE ){
MaximGordon 0:346a7fa07998 207 *n_spo2 = -999 ; // do not use SPO2 since valley loc is out of range
MaximGordon 0:346a7fa07998 208 *ch_spo2_valid = 0;
MaximGordon 0:346a7fa07998 209 return;
MaximGordon 0:346a7fa07998 210 }
MaximGordon 0:346a7fa07998 211 }
MaximGordon 0:346a7fa07998 212 // find max between two valley locations
MaximGordon 0:346a7fa07998 213 // and use ratio betwen AC compoent of Ir & Red and DC compoent of Ir & Red for SPO2
MaximGordon 0:346a7fa07998 214
MaximGordon 2:560e76e77544 215 for (k=0; k< n_exact_ir_valley_locs_count-1; k++){
MaximGordon 2:560e76e77544 216 n_y_dc_max= -16777216 ;
MaximGordon 2:560e76e77544 217 n_x_dc_max= - 16777216;
MaximGordon 2:560e76e77544 218 // printf("range=%d: %d\n ", n_exact_ir_valley_locs[k], n_exact_ir_valley_locs[k+1]);
MaximGordon 2:560e76e77544 219 if (n_exact_ir_valley_locs[k+1]-n_exact_ir_valley_locs[k] >10){
MaximGordon 2:560e76e77544 220 for (i=n_exact_ir_valley_locs[k]; i< n_exact_ir_valley_locs[k+1]; i++){
MaximGordon 0:346a7fa07998 221
MaximGordon 2:560e76e77544 222 if (n_x[i]> n_x_dc_max) {n_x_dc_max =n_x[i];n_x_dc_max_idx =i; }
MaximGordon 2:560e76e77544 223 if (n_y[i]> n_y_dc_max) {n_y_dc_max =n_y[i];n_y_dc_max_idx=i;}
MaximGordon 0:346a7fa07998 224 }
MaximGordon 2:560e76e77544 225 n_y_ac= (n_y[n_exact_ir_valley_locs[k+1]] - n_y[n_exact_ir_valley_locs[k] ] )*(n_y_dc_max_idx -n_exact_ir_valley_locs[k]); //red
MaximGordon 2:560e76e77544 226 n_y_ac= n_y[n_exact_ir_valley_locs[k]] + n_y_ac/ (n_exact_ir_valley_locs[k+1] - n_exact_ir_valley_locs[k]) ;
MaximGordon 0:346a7fa07998 227
MaximGordon 0:346a7fa07998 228
MaximGordon 2:560e76e77544 229 n_y_ac= n_y[n_y_dc_max_idx] - n_y_ac; // subracting linear DC compoenents from raw
MaximGordon 2:560e76e77544 230 n_x_ac= (n_x[n_exact_ir_valley_locs[k+1]] - n_x[n_exact_ir_valley_locs[k] ] )*(n_x_dc_max_idx -n_exact_ir_valley_locs[k]); // ir
MaximGordon 2:560e76e77544 231 n_x_ac= n_x[n_exact_ir_valley_locs[k]] + n_x_ac/ (n_exact_ir_valley_locs[k+1] - n_exact_ir_valley_locs[k]);
MaximGordon 2:560e76e77544 232 n_x_ac= n_x[n_y_dc_max_idx] - n_x_ac; // subracting linear DC compoenents from raw
MaximGordon 2:560e76e77544 233 n_nume=( n_y_ac *n_x_dc_max)>>7 ; //prepare X100 to preserve floating value
MaximGordon 2:560e76e77544 234 n_denom= ( n_x_ac *n_y_dc_max)>>7;
MaximGordon 2:560e76e77544 235 if (n_denom>0 && n_i_ratio_count <5 && n_nume != 0)
MaximGordon 0:346a7fa07998 236 {
MaximGordon 2:560e76e77544 237 n_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) ;
MaximGordon 2:560e76e77544 238 n_i_ratio_count++;
MaximGordon 0:346a7fa07998 239 }
MaximGordon 0:346a7fa07998 240 }
MaximGordon 0:346a7fa07998 241
MaximGordon 2:560e76e77544 242 // prlongf("n_ratio[%d]= %d n_exact_ir_valley_locs[k] =%d , n_exact_ir_valley_locs[%d] =%d \n",k, n_ratio[k] ,n_exact_ir_valley_locs[k] ,k+1, n_exact_ir_valley_locs[k+1] ) ;
MaximGordon 2:560e76e77544 243 // prlongf("n_nume= %d ,n_denom= %d n_y_ac = %d, n_x_dc_max = %d, n_x_ac= %d, n_y_dc_max = %d\n",n_nume, n_denom, n_y_ac ,n_x_dc_max ,n_x_ac ,n_y_dc_max );
MaximGordon 0:346a7fa07998 244
MaximGordon 0:346a7fa07998 245 }
MaximGordon 0:346a7fa07998 246
MaximGordon 2:560e76e77544 247 maxim_sort_ascend(n_ratio, n_i_ratio_count);
MaximGordon 2:560e76e77544 248 n_middle_idx= n_i_ratio_count/2;
MaximGordon 0:346a7fa07998 249
MaximGordon 2:560e76e77544 250 if (n_middle_idx >1)
MaximGordon 2:560e76e77544 251 n_ratio_average =( n_ratio[n_middle_idx-1] +n_ratio[n_middle_idx])/2; // use median
MaximGordon 0:346a7fa07998 252 else
MaximGordon 2:560e76e77544 253 n_ratio_average = n_ratio[n_middle_idx ];
MaximGordon 0:346a7fa07998 254
MaximGordon 2:560e76e77544 255 if( n_ratio_average>2 && n_ratio_average <184){
MaximGordon 2:560e76e77544 256 n_spo2_calc= uch_spo2_table[n_ratio_average] ;
MaximGordon 2:560e76e77544 257 *n_spo2 = n_spo2_calc ;
MaximGordon 2:560e76e77544 258 *ch_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
MaximGordon 0:346a7fa07998 259 }
MaximGordon 0:346a7fa07998 260 else{
MaximGordon 0:346a7fa07998 261 *n_spo2 = -999 ; // do not use SPO2 since signal ratio is out of range
MaximGordon 0:346a7fa07998 262 *ch_spo2_valid = 0;
MaximGordon 0:346a7fa07998 263 }
MaximGordon 0:346a7fa07998 264
MaximGordon 0:346a7fa07998 265
MaximGordon 0:346a7fa07998 266 }
MaximGordon 0:346a7fa07998 267
MaximGordon 0:346a7fa07998 268
MaximGordon 0:346a7fa07998 269 void maxim_find_peaks( int32_t *n_locs, int32_t *n_npks, int32_t *n_x, int32_t n_size, int32_t n_min_height, int32_t n_min_distance, int32_t n_max_num )
MaximGordon 0:346a7fa07998 270 /**
MaximGordon 0:346a7fa07998 271 * \brief Find peaks
MaximGordon 0:346a7fa07998 272 * \par Details
MaximGordon 0:346a7fa07998 273 * Find at most MAX_NUM peaks above MIN_HEIGHT separated by at least MIN_DISTANCE
MaximGordon 0:346a7fa07998 274 *
MaximGordon 0:346a7fa07998 275 * \retval None
MaximGordon 0:346a7fa07998 276 */
MaximGordon 0:346a7fa07998 277 {
MaximGordon 0:346a7fa07998 278 maxim_peaks_above_min_height( n_locs, n_npks, n_x, n_size, n_min_height );
MaximGordon 0:346a7fa07998 279 maxim_remove_close_peaks( n_locs, n_npks, n_x, n_min_distance );
MaximGordon 0:346a7fa07998 280 *n_npks = min( *n_npks, n_max_num );
MaximGordon 0:346a7fa07998 281 }
MaximGordon 0:346a7fa07998 282
MaximGordon 0:346a7fa07998 283 void maxim_peaks_above_min_height( int32_t *n_locs, int32_t *n_npks, int32_t *n_x, int32_t n_size, int32_t n_min_height )
MaximGordon 0:346a7fa07998 284 /**
MaximGordon 0:346a7fa07998 285 * \brief Find peaks above n_min_height
MaximGordon 0:346a7fa07998 286 * \par Details
MaximGordon 0:346a7fa07998 287 * Find all peaks above MIN_HEIGHT
MaximGordon 0:346a7fa07998 288 *
MaximGordon 0:346a7fa07998 289 * \retval None
MaximGordon 0:346a7fa07998 290 */
MaximGordon 0:346a7fa07998 291 {
MaximGordon 2:560e76e77544 292 int32_t i = 1, n_width;
MaximGordon 0:346a7fa07998 293 *n_npks = 0;
MaximGordon 0:346a7fa07998 294
MaximGordon 0:346a7fa07998 295 while (i < n_size-1){
MaximGordon 0:346a7fa07998 296 if (n_x[i] > n_min_height && n_x[i] > n_x[i-1]){ // find left edge of potential peaks
MaximGordon 2:560e76e77544 297 n_width = 1;
MaximGordon 2:560e76e77544 298 while (i+n_width < n_size && n_x[i] == n_x[i+n_width]) // find flat peaks
MaximGordon 2:560e76e77544 299 n_width++;
MaximGordon 2:560e76e77544 300 if (n_x[i] > n_x[i+n_width] && (*n_npks) < 15 ){ // find right edge of peaks
MaximGordon 0:346a7fa07998 301 n_locs[(*n_npks)++] = i;
MaximGordon 0:346a7fa07998 302 // for flat peaks, peak location is left edge
MaximGordon 2:560e76e77544 303 i += n_width+1;
MaximGordon 0:346a7fa07998 304 }
MaximGordon 0:346a7fa07998 305 else
MaximGordon 2:560e76e77544 306 i += n_width;
MaximGordon 0:346a7fa07998 307 }
MaximGordon 0:346a7fa07998 308 else
MaximGordon 0:346a7fa07998 309 i++;
MaximGordon 0:346a7fa07998 310 }
MaximGordon 0:346a7fa07998 311 }
MaximGordon 0:346a7fa07998 312
MaximGordon 0:346a7fa07998 313
MaximGordon 0:346a7fa07998 314 void maxim_remove_close_peaks( int32_t *n_locs, int32_t *n_npks, int32_t *n_x, int32_t n_min_distance )
MaximGordon 0:346a7fa07998 315 /**
MaximGordon 0:346a7fa07998 316 * \brief Remove peaks
MaximGordon 0:346a7fa07998 317 * \par Details
MaximGordon 0:346a7fa07998 318 * Remove peaks separated by less than MIN_DISTANCE
MaximGordon 0:346a7fa07998 319 *
MaximGordon 0:346a7fa07998 320 * \retval None
MaximGordon 0:346a7fa07998 321 */
MaximGordon 0:346a7fa07998 322 {
MaximGordon 0:346a7fa07998 323
MaximGordon 2:560e76e77544 324 int32_t i, j, n_old_npks, n_dist;
MaximGordon 0:346a7fa07998 325
MaximGordon 0:346a7fa07998 326 /* Order peaks from large to small */
MaximGordon 0:346a7fa07998 327 maxim_sort_indices_descend( n_x, n_locs, *n_npks );
MaximGordon 0:346a7fa07998 328
MaximGordon 0:346a7fa07998 329 for ( i = -1; i < *n_npks; i++ ){
MaximGordon 2:560e76e77544 330 n_old_npks = *n_npks;
MaximGordon 0:346a7fa07998 331 *n_npks = i+1;
MaximGordon 2:560e76e77544 332 for ( j = i+1; j < n_old_npks; j++ ){
MaximGordon 2:560e76e77544 333 n_dist = n_locs[j] - ( i == -1 ? -1 : n_locs[i] ); // lag-zero peak of autocorr is at index -1
MaximGordon 2:560e76e77544 334 if ( n_dist > n_min_distance || n_dist < -n_min_distance )
MaximGordon 0:346a7fa07998 335 n_locs[(*n_npks)++] = n_locs[j];
MaximGordon 0:346a7fa07998 336 }
MaximGordon 0:346a7fa07998 337 }
MaximGordon 0:346a7fa07998 338
MaximGordon 0:346a7fa07998 339 // Resort indices longo ascending order
MaximGordon 0:346a7fa07998 340 maxim_sort_ascend( n_locs, *n_npks );
MaximGordon 0:346a7fa07998 341 }
MaximGordon 0:346a7fa07998 342
MaximGordon 0:346a7fa07998 343 void maxim_sort_ascend(int32_t *n_x, int32_t n_size)
MaximGordon 0:346a7fa07998 344 /**
MaximGordon 0:346a7fa07998 345 * \brief Sort array
MaximGordon 0:346a7fa07998 346 * \par Details
MaximGordon 0:346a7fa07998 347 * Sort array in ascending order (insertion sort algorithm)
MaximGordon 0:346a7fa07998 348 *
MaximGordon 0:346a7fa07998 349 * \retval None
MaximGordon 0:346a7fa07998 350 */
MaximGordon 0:346a7fa07998 351 {
MaximGordon 2:560e76e77544 352 int32_t i, j, n_temp;
MaximGordon 0:346a7fa07998 353 for (i = 1; i < n_size; i++) {
MaximGordon 2:560e76e77544 354 n_temp = n_x[i];
MaximGordon 2:560e76e77544 355 for (j = i; j > 0 && n_temp < n_x[j-1]; j--)
MaximGordon 0:346a7fa07998 356 n_x[j] = n_x[j-1];
MaximGordon 2:560e76e77544 357 n_x[j] = n_temp;
MaximGordon 0:346a7fa07998 358 }
MaximGordon 0:346a7fa07998 359 }
MaximGordon 0:346a7fa07998 360
MaximGordon 0:346a7fa07998 361 void maxim_sort_indices_descend( int32_t *n_x, int32_t *n_indx, int32_t n_size)
MaximGordon 0:346a7fa07998 362 /**
MaximGordon 0:346a7fa07998 363 * \brief Sort indices
MaximGordon 0:346a7fa07998 364 * \par Details
MaximGordon 0:346a7fa07998 365 * Sort indices according to descending order (insertion sort algorithm)
MaximGordon 0:346a7fa07998 366 *
MaximGordon 0:346a7fa07998 367 * \retval None
MaximGordon 0:346a7fa07998 368 */
MaximGordon 0:346a7fa07998 369 {
MaximGordon 2:560e76e77544 370 int32_t i, j, n_temp;
MaximGordon 0:346a7fa07998 371 for (i = 1; i < n_size; i++) {
MaximGordon 2:560e76e77544 372 n_temp = n_indx[i];
MaximGordon 2:560e76e77544 373 for (j = i; j > 0 && n_x[n_temp] > n_x[n_indx[j-1]]; j--)
MaximGordon 0:346a7fa07998 374 n_indx[j] = n_indx[j-1];
MaximGordon 2:560e76e77544 375 n_indx[j] = n_temp;
MaximGordon 0:346a7fa07998 376 }
MaximGordon 0:346a7fa07998 377 }
MaximGordon 0:346a7fa07998 378