GMIN-2992: Start with -dev trigger before switching to -any-motion

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

diff --git a/transform.c b/transform.c
index e8fa707..e86fe1a 100644 (file)
--- a/transform.c
+++ b/transform.c
@@ -188,6 +188,61 @@ 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 i;
+       float total;
+       int f;
+       int sampling_rate = (int) si->sampling_rate;
+       int history_size;
+
+       /* Don't denoise anything if we have less than two samples per second */
+       if (sampling_rate < 2)
+               return;
+
+       /* Restrict window size in case of a very high sampling rate */
+       if (sampling_rate > 100)
+               history_size = 100;
+       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)
+               return; /* Unlikely, but still... */
+
+       /* Update initialized samples count */
+       if (si->history_entries < si->history_size)
+               si->history_entries++;
+
+       /* Record new sample */
+       for (f=0; f < num_fields; f++)
+               si->history[si->history_index * num_fields + f] = data->data[f];
+
+       /* Update our rolling index (next evicted cell) */
+       si->history_index = (si->history_index + 1) % si->history_size;
+
+       /* For now simply compute a mobile mean for each field */
+       for (f=0; f < num_fields; f++) {
+               total = 0;
+
+               for (i=0; i < si->history_entries; i++)
+                               total += si->history[i * num_fields + f];
+
+               /* Output filtered data */
+               data->data[f] = total / si->history_entries;
+       }
+}
+
+
 static int finalize_sample_default(int s, struct sensors_event_t* data)
 {
        int i           = sensor_info[s].catalog_index;
@@ -199,15 +254,21 @@ static int finalize_sample_default(int s, struct sensors_event_t* data)
 
        switch (sensor_type) {
                case SENSOR_TYPE_ACCELEROMETER:
+                       if (sensor_info[s].quirks & QUIRK_NOISY)
+                               denoise(&sensor_info[s], data, 3);
                        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);
                        break;
 
                case SENSOR_TYPE_GYROSCOPE:
                case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
                        calibrate_gyro(data, &sensor_info[s]);
+                       if (sensor_info[s].quirks & QUIRK_NOISY)
+                               denoise(&sensor_info[s], data, 3);
                        break;
 
                case SENSOR_TYPE_LIGHT: