src/fusion-sensor/pedometer/zero_crossing_step_detection.cpp

   1 /*
   2  *  Copyright (c) 2016-2017 Samsung Electronics Co., Ltd.
   3  *
   4  *  Licensed under the Apache License, Version 2.0 (the "License");
   5  *  you may not use this file except in compliance with the License.
   6  *  You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  *  Unless required by applicable law or agreed to in writing, software
  11  *  distributed under the License is distributed on an "AS IS" BASIS,
  12  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  *  See the License for the specific language governing permissions and
  14  *  limitations under the License.
  15  */
  16
  17 #include "zero_crossing_step_detection.h"
  18
  19 static bool detect_zero_crossing(double last_accel, double new_accel, bool up)
  20 {
  21         if (up)
  22                 return (last_accel < 0 && new_accel >= 0);
  23
  24         return (last_accel > 0 && new_accel <= 0);
  25 }
  26
  27 zero_crossing_step_detection::zero_crossing_step_detection(bool up)
  28 : m_up(up)
  29 , m_last_acceleration(0)
  30 , m_last_timestamp(UNKNOWN_TIMESTAMP)
  31 , m_last_zero_crossing_time(UNKNOWN_TIMESTAMP)
  32 , m_time_sum(0)
  33 {
  34 }
  35
  36 zero_crossing_step_detection::~zero_crossing_step_detection()
  37 {
  38 }
  39
  40 bool zero_crossing_step_detection::detect_step(timestamp_t timestamp, double acceleration)
  41 {
  42         bool step_detected = false;
  43
  44         if (m_last_timestamp != UNKNOWN_TIMESTAMP) {
  45                 // zero crossing detected
  46                 if (detect_zero_crossing(m_last_acceleration, acceleration, m_up)) {
  47                         m_time_sum += timestamp - m_last_timestamp;
  48                         m_last_timestamp = timestamp;
  49                         m_last_zero_crossing_time = timestamp;
  50                         step_detected = true;
  51                 }
  52         } else {
  53                 m_last_timestamp = timestamp;
  54         }
  55         m_last_acceleration = acceleration;
  56         return step_detected;
  57 }
  58
  59 void zero_crossing_step_detection::clr_time_sum() {
  60         m_time_sum = 0.0;
  61 }
  62
  63 double zero_crossing_step_detection::get_time_sum() {
  64         return m_time_sum / 1E9;
  65 }
  66
  67 void zero_crossing_step_detection::reset(void)
  68 {
  69         m_last_acceleration = 0;
  70         m_time_sum = 0;
  71         m_last_timestamp = UNKNOWN_TIMESTAMP;
  72         m_last_zero_crossing_time = UNKNOWN_TIMESTAMP;
  73 }