Min/Max delay for Light and Temperature

[android-x86/hardware-intel-libsensors.git] / transform.c

diff --git a/transform.c b/transform.c
index ed66613..8b525d1 100644 (file)
--- a/transform.c
+++ b/transform.c
@@ -12,6 +12,7 @@
 #include "description.h"
 #include "transform.h"
 #include "utils.h"
+#include "filtering.h"
 
 /*----------------------------------------------------------------------------*/
 
@@ -189,58 +190,74 @@ static void reorder_fields(float* data,   unsigned char map[MAX_CHANNELS])
 
 
 static void denoise (struct sensor_info_t* si, struct sensors_event_t* data,
-                    int num_fields)
+                    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;
-       float total;
        int f;
        int sampling_rate = (int) si->sampling_rate;
+       int history_size;
+       int history_full = 0;
 
-       /* We're recording 1s worth of samples ; need suitable sampling rate */
-       if (sampling_rate < 1)
+       /* Don't denoise anything if we have less than two samples per second */
+       if (sampling_rate < 2)
                return;
 
-       /* Reset history if a new sampling rate is detected */
-       if (si->history_size != sampling_rate) {
-               si->history_size = sampling_rate;
+       /* 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)
+       if (!si->history || !si->history_sum)
                return; /* Unlikely, but still... */
 
-       /* Populate beginning of array as we go */
-       if (si->history_entries < si->history_size) {
-               for (f=0; f<num_fields; f++)
-                       si->history[si->history_entries * num_fields + f] =
-                               data->data[f];
-
+       /* 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;
        }
 
-       /* Once we get enough data, start filtering */
-       if (si->history_entries == si->history_size) {
-
-               /* For now simply compute a mobile mean */
-               for (f=0; f<num_fields; f++) {
-                       total = 0;
-
-                       for (i=0; i<si->history_size; i++)
-                               total += si->history[i * num_fields + f];
-
-                       si->history[si->history_index * num_fields + f] =
-                               data->data[f];
-
-                       /* Output filtered data */
-                       data->data[f] = total / si->history_size;
-               }
-
-               /* Update our rolling index (next evicted cell) */
-               si->history_index = (si->history_index + 1) % si->history_size;
-       }
+       /* Update our rolling index (next evicted cell) */
+       si->history_index = (si->history_index + 1) % si->history_size;
 }
 
 
@@ -255,17 +272,24 @@ static int finalize_sample_default(int s, struct sensors_event_t* data)
 
        switch (sensor_type) {
                case SENSOR_TYPE_ACCELEROMETER:
+                       /* Always consider the accelerometer accurate */
+                       data->acceleration.status = SENSOR_STATUS_ACCURACY_HIGH;
+                       if (sensor_info[s].quirks & QUIRK_NOISY)
+                               denoise(&sensor_info[s], data, 3, 20);
                        break;
 
                case SENSOR_TYPE_MAGNETIC_FIELD:
                        calibrate_compass (data, &sensor_info[s], get_timestamp());
                        if (sensor_info[s].quirks & QUIRK_NOISY)
-                               denoise(&sensor_info[s], data, 3);
+                               denoise(&sensor_info[s], data, 3, 100);
                        break;
 
                case SENSOR_TYPE_GYROSCOPE:
                case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
-                       calibrate_gyro(data, &sensor_info[s]);
+                       if (!(sensor_info[s].quirks & QUIRK_TERSE_DRIVER))
+                               calibrate_gyro(data, &sensor_info[s]);
+                       if (sensor_info[s].quirks & QUIRK_NOISY)
+                               denoise_median(data, &sensor_info[s]);
                        break;
 
                case SENSOR_TYPE_LIGHT: