}
-static void denoise (struct sensor_info_t* si, struct sensors_event_t* data,
- int num_fields, int max_samples)
+static void clamp_gyro_readings_to_zero (int s, struct sensors_event_t* data)
{
- /*
- * 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.
- */
+ float x, y, z;
+ float near_zero;
- 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));
- }
- }
+ switch (sensor_info[s].type) {
+ case SENSOR_TYPE_GYROSCOPE:
+ x = data->data[0];
+ y = data->data[1];
+ z = data->data[2];
+ break;
- if (!si->history || !si->history_sum)
- return; /* Unlikely, but still... */
+ case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
+ x = data->data[0] - data->uncalibrated_gyro.bias[0];
+ y = data->data[1] - data->uncalibrated_gyro.bias[1];
+ z = data->data[2] - data->uncalibrated_gyro.bias[2];
+ break;
- /* Update initialized samples count */
- if (si->history_entries < si->history_size)
- si->history_entries++;
- else
- history_full = 1;
+ default:
+ return;
+ }
- /* 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];
+ /* If we're calibrated, don't filter out as much */
+ if (sensor_info[s].cal_level > 0)
+ near_zero = 0.02; /* rad/s */
+ else
+ near_zero = 0.1;
- si->history[si->history_index * num_fields + f] = data->data[f];
- si->history_sum[f] += data->data[f];
+ /* If motion on all axes is small enough */
+ if (fabs(x) < near_zero && fabs(y) < near_zero && fabs(z) < near_zero) {
- /* For now simply compute a mobile mean for each field */
- /* and output filtered data */
- data->data[f] = si->history_sum[f] / si->history_entries;
+ /*
+ * Report that we're not moving at all... but not exactly zero
+ * as composite sensors (orientation, rotation vector) don't
+ * seem to react very well to it.
+ */
+ switch (sensor_info[s].type) {
+ case SENSOR_TYPE_GYROSCOPE:
+ data->data[0] *= 0.000001;
+ data->data[1] *= 0.000001;
+ data->data[2] *= 0.000001;
+ break;
+
+ case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
+ data->data[0]= data->uncalibrated_gyro.bias[0]
+ + 0.000001 * x;
+ data->data[1]= data->uncalibrated_gyro.bias[1]
+ + 0.000001 * y;
+ data->data[2]= data->uncalibrated_gyro.bias[2]
+ + 0.000001 * z;
+ break;
+ }
}
-
- /* Update our rolling index (next evicted cell) */
- si->history_index = (si->history_index + 1) % si->history_size;
}
/* 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);
+ denoise(s, data);
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, 100);
+ denoise(s, data);
break;
case SENSOR_TYPE_GYROSCOPE:
- case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
+
/*
* Report medium accuracy by default ; higher accuracy
* levels will be reported once, and if, we achieve
*/
data->gyro.status = SENSOR_STATUS_ACCURACY_MEDIUM;
+ /* ... fall through */
+
+ case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
+
/*
* We're only trying to calibrate data from continuously
* firing gyroscope drivers, as motion based ones use
* events that can disturb our mean or stddev.
*/
if (sensor_info[s].quirks & QUIRK_NOISY) {
- denoise_median(&sensor_info[s], data, 3);
if((sensor_info[s].selected_trigger !=
sensor_info[s].motion_trigger_name) &&
sensor_info[s].event_count < MIN_SAMPLES)
return 0;
+
+ denoise(s, data);
}
+
+ /* Clamp near zero moves to (0,0,0) if appropriate */
+ clamp_gyro_readings_to_zero(s, data);
break;
case SENSOR_TYPE_LIGHT:
break;
}
- /* Add this event to our global records, for filtering purposes */
- record_sample(s, data);
-
return 1; /* Return sample to Android */
}
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