-#include <stdlib.h>
+/*
+ * Copyright (C) 2014 Intel Corporation.
+ */
+
#include <hardware/sensors.h>
-#include <math.h>
-#include <pthread.h>
#include <utils/Log.h>
#include "common.h"
#include "filtering.h"
+#include "description.h"
-
-struct filter_median
+typedef struct
{
float* buff;
unsigned int idx;
unsigned int count;
unsigned int sample_size;
-};
+}
+filter_median_t;
-static unsigned int partition(float* list, unsigned int left,
- unsigned int right, unsigned int pivot_index)
+
+static unsigned int partition (float* list, unsigned int left, unsigned int right, unsigned int pivot_index)
{
unsigned int i;
unsigned int store_index = left;
float aux;
float pivot_value = list[pivot_index];
- // swap list[pivotIndex] and list[right]
+ /* Swap list[pivotIndex] and list[right] */
aux = list[pivot_index];
list[pivot_index] = list[right];
list[right] = aux;
{
if (list[i] < pivot_value)
{
- // swap list[store_index] and list[i]
+ /* Swap list[store_index] and list[i] */
aux = list[store_index];
list[store_index] = list[i];
list[i] = aux;
store_index++;
}
}
- //swap list[right] and list[store_index]
+
+ /* Swap list[right] and list[store_index] */
aux = list[right];
list[right] = list[store_index];
list[store_index] = aux;
return store_index;
}
-/* http://en.wikipedia.org/wiki/Quickselect */
-float median(float* queue, unsigned int size)
+
+static float median (float* queue, unsigned int size)
{
+ /* http://en.wikipedia.org/wiki/Quickselect */
+
unsigned int left = 0;
unsigned int right = size - 1;
unsigned int pivot_index;
return temp[left];
}
-void denoise_median_init(int s, unsigned int num_fields,
- unsigned int max_samples)
+
+static void denoise_median_init (int s, unsigned int num_fields, unsigned int max_samples)
{
- struct filter_median* f_data = (struct filter_median*) calloc(1, sizeof(struct filter_median));
- f_data->buff = (float*)calloc(max_samples,
- sizeof(float) * num_fields);
+ filter_median_t* f_data = (filter_median_t*) malloc(sizeof(filter_median_t));
+
+ f_data->buff = (float*) calloc(max_samples, sizeof(float) * num_fields);
f_data->sample_size = max_samples;
f_data->count = 0;
f_data->idx = 0;
- sensor_info[s].filter = f_data;
+ sensor[s].filter = f_data;
}
-void denoise_median_release(int s)
+
+static void denoise_median_reset (sensor_info_t* info)
{
- if (!sensor_info[s].filter)
+ filter_median_t* f_data = (filter_median_t*) info->filter;
+
+ if (!f_data)
return;
- free(((struct filter_median*)sensor_info[s].filter)->buff);
- free(sensor_info[s].filter);
- sensor_info[s].filter = NULL;
+ f_data->count = 0;
+ f_data->idx = 0;
}
-void denoise_median(struct sensor_info_t* info, struct sensors_event_t* data,
- unsigned int num_fields)
+
+static void denoise_median (sensor_info_t* info, sensors_event_t* data, unsigned int num_fields)
{
float x, y, z;
float scale;
unsigned int field, offset;
- struct filter_median* f_data = (struct filter_median*) info->filter;
+ filter_median_t* f_data = (filter_median_t*) info->filter;
if (!f_data)
return;
+ /* If we are at event count 1 reset the indices */
+ if (info->event_count == 1)
+ denoise_median_reset(info);
if (f_data->count < f_data->sample_size)
f_data->count++;
}
+static void denoise_average (sensor_info_t* si, sensors_event_t* data, int num_fields, int max_samples)
+{
+ /*
+ * Smooth out incoming data using a moving average over a number of
+ * samples. We accumulate one second worth of samples, or max_samples,
+ * depending on which is lower.
+ */
+
+ int i;
+ int f;
+ int sampling_rate = (int) si->sampling_rate;
+ int history_size;
+ int history_full = 0;
+
+ /* Don't denoise anything if we have less than two samples per second */
+ if (sampling_rate < 2)
+ return;
+
+ /* Restrict window size to the min of sampling_rate and max_samples */
+ if (sampling_rate > max_samples)
+ history_size = max_samples;
+ else
+ history_size = sampling_rate;
+
+ /* Reset history if we're operating on an incorrect window size */
+ if (si->history_size != history_size) {
+ si->history_size = history_size;
+ si->history_entries = 0;
+ si->history_index = 0;
+ si->history = (float*) realloc(si->history, si->history_size * num_fields * sizeof(float));
+ if (si->history) {
+ si->history_sum = (float*) realloc(si->history_sum, num_fields * sizeof(float));
+ if (si->history_sum)
+ memset(si->history_sum, 0, num_fields * sizeof(float));
+ }
+ }
+
+ if (!si->history || !si->history_sum)
+ return; /* Unlikely, but still... */
+
+ /* Update initialized samples count */
+ if (si->history_entries < si->history_size)
+ si->history_entries++;
+ else
+ history_full = 1;
+
+ /* Record new sample and calculate the moving sum */
+ for (f=0; f < num_fields; f++) {
+ /** A field is going to be overwritten if history is full, so decrease the history sum */
+ if (history_full)
+ si->history_sum[f] -=
+ si->history[si->history_index * num_fields + f];
+
+ si->history[si->history_index * num_fields + f] = data->data[f];
+ si->history_sum[f] += data->data[f];
+
+ /* For now simply compute a mobile mean for each field and output filtered data */
+ data->data[f] = si->history_sum[f] / si->history_entries;
+ }
+
+ /* Update our rolling index (next evicted cell) */
+ si->history_index = (si->history_index + 1) % si->history_size;
+}
+
+
+void setup_noise_filtering (int s)
+{
+ char filter_buf[MAX_NAME_SIZE];
+
+ /* By default, don't apply filtering */
+ sensor[s].filter_type = FILTER_TYPE_NONE;
+
+ /* If noisy, start with default filter for sensor type */
+ if (sensor[s].quirks & QUIRK_NOISY)
+ switch (sensor[s].type) {
+ case SENSOR_TYPE_GYROSCOPE:
+ sensor[s].filter_type = FILTER_TYPE_MEDIAN;
+ break;
+
+ case SENSOR_TYPE_MAGNETIC_FIELD:
+ sensor[s].filter_type = FILTER_TYPE_MOVING_AVERAGE;
+ break;
+ }
+
+ /* Use whatever was specified if there's an explicit configuration choice for this sensor */
+
+ filter_buf[0] = '\0';
+ sensor_get_st_prop(s, "filter", filter_buf);
+
+ if (strstr(filter_buf, "median"))
+ sensor[s].filter_type = FILTER_TYPE_MEDIAN;
+
+ if (strstr(filter_buf, "average"))
+ sensor[s].filter_type = FILTER_TYPE_MOVING_AVERAGE;
+
+ switch (sensor[s].filter_type) {
+ case FILTER_TYPE_MEDIAN:
+ denoise_median_init(s, 3, 5);
+ break;
+ }
+}
+
+
+void denoise (int s, sensors_event_t* data)
+{
+ switch (sensor[s].filter_type) {
+ case FILTER_TYPE_MEDIAN:
+ denoise_median(&sensor[s], data, 3);
+ break;
+
+ case FILTER_TYPE_MOVING_AVERAGE:
+ denoise_average(&sensor[s], data, 3 , 20);
+ break;
+ }
+}
+
+
+void release_noise_filtering_data (int s)
+{
+ void *buff;
+
+ /* Delete moving average structures */
+ if (sensor[s].history) {
+ free(sensor[s].history);
+ sensor[s].history = NULL;
+ sensor[s].history_size = 0;
+ if (sensor[s].history_sum) {
+ free(sensor[s].history_sum);
+ sensor[s].history_sum = NULL;
+ }
+ }
+
+ /* Delete median filter structures */
+ if (sensor[s].filter) {
+ buff = ((filter_median_t*) sensor[s].filter)->buff;
+
+ if (buff)
+ free(buff);
+
+ free(sensor[s].filter);
+ sensor[s].filter = NULL;
+ }
+}
+
+
#define GLOBAL_HISTORY_SIZE 100
-struct recorded_sample_t
+typedef struct
{
int sensor;
int motion_trigger;
sensors_event_t data;
-};
+}
+recorded_sample_t;
/*
- * This is a circular buffer holding the last GLOBAL_HISTORY_SIZE events,
- * covering the entire sensor collection. It is intended as a way to correlate
- * data coming from active sensors, no matter the sensor type, over a recent
- * window of time. The array is not sorted ; we simply evict the oldest cell
- * (by insertion time) and replace its contents. Timestamps don't necessarily
- * grow monotonically as they tell the data acquisition type, and that there can
- * be a delay between acquisition and insertion into this table.
+ * This is a circular buffer holding the last GLOBAL_HISTORY_SIZE events, covering the entire sensor collection. It is intended as a way to correlate
+ * data coming from active sensors, no matter the sensor type, over a recent window of time. The array is not sorted ; we simply evict the oldest cell
+ * (by insertion time) and replace its contents. Timestamps don't necessarily grow monotonically as they tell the data acquisition type, and that there
+ * can be a delay between acquisition and insertion into this table.
*/
-static struct recorded_sample_t global_history[GLOBAL_HISTORY_SIZE];
+static recorded_sample_t global_history[GLOBAL_HISTORY_SIZE];
static int initialized_entries; /* How many of these are initialized */
static int insertion_index; /* Index of sample to evict next time */
-void record_sample (int s, const struct sensors_event_t* event)
+void record_sample (int s, const sensors_event_t* event)
{
- struct recorded_sample_t *cell;
+ recorded_sample_t *cell;
int i;
/* Don't record duplicate samples, as they are not useful for filters */
- if (sensor_info[s].report_pending == DATA_DUPLICATE)
+ if (sensor[s].report_pending == DATA_DUPLICATE)
return;
if (initialized_entries == GLOBAL_HISTORY_SIZE) {
cell = &global_history[i];
- cell->sensor = s;
+ cell->sensor = s;
- cell->motion_trigger = (sensor_info[s].selected_trigger ==
- sensor_info[s].motion_trigger_name);
+ cell->motion_trigger = (sensor[s].selected_trigger == sensor[s].motion_trigger_name);
memcpy(&cell->data, event, sizeof(sensors_event_t));
}
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