apps/CameraITS/tests/scene0/test_vibration_restriction.py

# Copyright 2019 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import math
import os.path
import time

import its.caps
import its.device
import matplotlib
from matplotlib import pylab
import numpy as np

NAME = os.path.basename(__file__).split(".")[0]

# if the var(x) > var(stable) * this threshold, then device is considered vibrated
# Test results shows the variance difference is larger for higher sampling frequency
# This threshold is good enough for 50hz samples.
THRESHOLD_VIBRATION_VAR = 10.0

# Match CameraDevice.java constant
AUDIO_RESTRICTION_NONE = 0
AUDIO_RESTRICTION_VIBRATION = 1
AUDIO_RESTRICTION_VIBRATION_SOUND = 2

# The sleep time between vibrator on/off to avoid getting some residual vibrations
SLEEP_BETWEEN_SAMPLES_SEC = 0.5
# The sleep time to collect sensor samples
SLEEP_COLLECT_SAMPLES_SEC = 1.0

def calc_magnitude(e):
    x = e["x"]
    y = e["y"]
    z = e["z"]
    return math.sqrt(x*x + y*y + z*z)

def main():
    """Test vibrations can be muted by the camera audio restriction API."""

    with its.device.ItsSession() as cam:
        props = cam.get_camera_properties()
        props = cam.override_with_hidden_physical_camera_props(props)
        sensors = cam.get_sensors()

        its.caps.skip_unless(sensors.get("accel") and sensors.get("vibrator"))

        cam.start_sensor_events()
        pattern_ms = [0, 1000]
        cam.do_vibrate(pattern_ms)
        test_length_second = sum(pattern_ms) / 1000
        time.sleep(test_length_second)
        events = cam.get_sensor_events()
        print "Accelerometer events over %ds: %d " % (test_length_second, len(events["accel"]))
        times_ms = [e["time"]/float(1e6) for e in events["accel"]]
        t0 = times_ms[0]
        times_ms = [t - t0 for t in times_ms]
        magnitudes = [calc_magnitude(e) for e in events["accel"]]
        var_w_vibration = np.var(magnitudes)

        time.sleep(SLEEP_BETWEEN_SAMPLES_SEC)
        cam.start_sensor_events()
        time.sleep(SLEEP_COLLECT_SAMPLES_SEC)
        events = cam.get_sensor_events()
        magnitudes = [calc_magnitude(e) for e in events["accel"]]
        var_wo_vibration = np.var(magnitudes)

        if var_w_vibration < var_wo_vibration * THRESHOLD_VIBRATION_VAR:
            print "Warning: unable to detect vibration, variance w/wo vibration too close:"\
                    " %f/%f. Make sure device is on non-dampening surface" % (
                    var_w_vibration, var_wo_vibration)

        time.sleep(SLEEP_BETWEEN_SAMPLES_SEC)
        cam.start_sensor_events()
        cam.set_audio_restriction(AUDIO_RESTRICTION_VIBRATION)
        cam.do_vibrate(pattern_ms)
        time.sleep(SLEEP_COLLECT_SAMPLES_SEC)
        events = cam.get_sensor_events()
        magnitudes = [calc_magnitude(e) for e in events["accel"]]
        var_w_vibration_restricted = np.var(magnitudes)

        print "Accel variance with/without/restricted vibration (%f, %f, %f)" % (
                var_w_vibration, var_wo_vibration, var_w_vibration_restricted)

        e_msg = "Device vibrated while vibration is muted"
        assert var_w_vibration_restricted < var_wo_vibration * THRESHOLD_VIBRATION_VAR, e_msg

if __name__ == "__main__":
    main()