+/*
+ * Copyright (C) 2014-2015 Intel Corporation.
+ */
+
+#include <ctype.h>
#include <stdlib.h>
#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_t
+typedef struct
{
float* buff;
unsigned int idx;
unsigned int count;
unsigned int sample_size;
-};
+}
+filter_median_t;
+
+
+typedef struct
+{
+ int max_samples; /* Maximum averaging window size */
+ int num_fields; /* Number of fields per sample (usually 3) */
+ float *history; /* Working buffer containing recorded samples */
+ float *history_sum; /* The current sum of the history elements */
+ int history_size; /* Number of recorded samples */
+ int history_entries; /* How many of these are initialized */
+ int history_index; /* Index of sample to evict next time */
+}
+filter_average_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;
}
-static 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_t* f_data = (struct filter_median_t*)
- malloc(sizeof(struct filter_median_t));
+ 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;
}
-static void denoise_median_reset (struct sensor_info_t* info)
+static void denoise_average_init (int s, unsigned int num_fields, unsigned int max_samples)
+{
+ filter_average_t* filter = (filter_average_t*) malloc(sizeof(filter_average_t));
+
+ if (filter) {
+ memset(filter, 0, sizeof(filter_average_t));
+ filter->max_samples = max_samples;
+ filter->num_fields = num_fields;
+ }
+
+ sensor[s].filter = filter;
+}
+
+
+static void denoise_median_reset (sensor_info_t* info)
{
- struct filter_median_t* f_data = (struct filter_median_t*) info->filter;
+ filter_median_t* f_data = (filter_median_t*) info->filter;
if (!f_data)
return;
}
-static 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_t* f_data = (struct filter_median_t*) info->filter;
+ filter_median_t* f_data = (filter_median_t*) info->filter;
if (!f_data)
return;
}
-static void denoise_average ( struct sensor_info_t* si,
- struct sensors_event_t* data,
- int num_fields, int max_samples)
+static void denoise_average (sensor_info_t* si, sensors_event_t* data)
{
/*
* Smooth out incoming data using a moving average over a number of
* depending on which is lower.
*/
- int i;
int f;
int sampling_rate = (int) si->sampling_rate;
int history_size;
int history_full = 0;
+ filter_average_t* filter;
/* Don't denoise anything if we have less than two samples per second */
if (sampling_rate < 2)
return;
+ filter = (filter_average_t*) si->filter;
+
+ if (!filter)
+ return;
+
/* Restrict window size to the min of sampling_rate and max_samples */
- if (sampling_rate > max_samples)
- history_size = max_samples;
+ if (sampling_rate > filter->max_samples)
+ history_size = filter->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 (filter->history_size != history_size) {
+ filter->history_size = history_size;
+ filter->history_entries = 0;
+ filter->history_index = 0;
+ filter->history = (float*) realloc(filter->history, filter->history_size * filter->num_fields * sizeof(float));
+ if (filter->history) {
+ filter->history_sum = (float*) realloc(filter->history_sum, filter->num_fields * sizeof(float));
+ if (filter->history_sum)
+ memset(filter->history_sum, 0, filter->num_fields * sizeof(float));
}
}
- if (!si->history || !si->history_sum)
+ if (!filter->history || !filter->history_sum)
return; /* Unlikely, but still... */
/* Update initialized samples count */
- if (si->history_entries < si->history_size)
- si->history_entries++;
+ if (filter->history_entries < filter->history_size)
+ filter->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
- */
+ for (f=0; f < filter->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];
+ filter->history_sum[f] -= filter->history[filter->history_index * filter->num_fields + f];
- si->history[si->history_index * num_fields + f] = data->data[f];
- si->history_sum[f] += data->data[f];
+ filter->history[filter->history_index * filter->num_fields + f] = data->data[f];
+ filter->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;
+ /* For now simply compute a mobile mean for each field and output filtered data */
+ data->data[f] = filter->history_sum[f] / filter->history_entries;
}
/* Update our rolling index (next evicted cell) */
- si->history_index = (si->history_index + 1) % si->history_size;
+ filter->history_index = (filter->history_index + 1) % filter->history_size;
}
void setup_noise_filtering (int s)
{
+ char filter_buf[MAX_NAME_SIZE];
+ int num_fields;
+ char* cursor;
+ int window_size = 0;
+
+ /* By default, don't apply filtering */
+ sensor[s].filter_type = FILTER_TYPE_NONE;
+
+ /* Restrict filtering to a few sensor types for now */
switch (sensor[s].type) {
- case SENSOR_TYPE_GYROSCOPE:
- denoise_median_init(s, 3, 5);
+ case SENSOR_TYPE_ACCELEROMETER:
+ case SENSOR_TYPE_GYROSCOPE:
+ case SENSOR_TYPE_MAGNETIC_FIELD:
+ num_fields = 3 /* x,y,z */;
+ break;
+
+ default:
+ return; /* No filtering */
+ }
+
+ /* 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);
+
+ cursor = strstr(filter_buf, "median");
+ if (cursor)
+ sensor[s].filter_type = FILTER_TYPE_MEDIAN;
+ else {
+ cursor = strstr(filter_buf, "average");
+ if (cursor)
+ sensor[s].filter_type = FILTER_TYPE_MOVING_AVERAGE;
+ }
+
+ /* Check if an integer is part of the string, and use it as window size */
+ if (cursor) {
+ while (*cursor && !isdigit(*cursor))
+ cursor++;
+
+ if (*cursor)
+ window_size = atoi(cursor);
+ }
+
+ switch (sensor[s].filter_type) {
+
+ case FILTER_TYPE_MEDIAN:
+ denoise_median_init(s, num_fields, window_size ? window_size : 5);
+ break;
+
+ case FILTER_TYPE_MOVING_AVERAGE:
+ denoise_average_init(s, num_fields, window_size ? window_size: 20);
break;
}
}
-void denoise (int s, struct sensors_event_t* data)
+void denoise (int s, sensors_event_t* data)
{
- switch (sensor[s].type) {
- case SENSOR_TYPE_GYROSCOPE:
+ switch (sensor[s].filter_type) {
+
+ case FILTER_TYPE_MEDIAN:
denoise_median(&sensor[s], data, 3);
break;
- case SENSOR_TYPE_MAGNETIC_FIELD:
- denoise_average(&sensor[s], data, 3 , 20);
+ case FILTER_TYPE_MOVING_AVERAGE:
+ denoise_average(&sensor[s], data);
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;
- }
- }
+ void *buf;
+
+ if (!sensor[s].filter)
+ return;
+
+ switch (sensor[s].filter_type) {
- /* Delete median filter structures */
- if (sensor[s].filter) {
- buff = ((struct filter_median_t*)sensor[s].filter)->buff;
+ case FILTER_TYPE_MEDIAN:
+ buf = ((filter_median_t*) sensor[s].filter)->buff;
+ if (buf)
+ free(buf);
+ break;
- if (buff)
- free(buff);
+ case FILTER_TYPE_MOVING_AVERAGE:
+ buf = ((filter_average_t*) sensor[s].filter)->history;
+ if (buf)
+ free(buf);
- free(sensor[s].filter);
- sensor[s].filter = NULL;
+ buf = ((filter_average_t*) sensor[s].filter)->history_sum;
+ if (buf)
+ free(buf);
+ break;
}
+
+ 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 */
cell->sensor = s;
- cell->motion_trigger = (sensor[s].selected_trigger ==
- sensor[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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