extractors.dead_reckon¶

Module: `extractors.dead_reckon`¶

Attempt dead reckoning (estimating position) from accelerometer data.

Authors:

Arno Klein, 2015 (arno@sagebase.org) http://binarybottle.com

Functions¶

mhealthx.extractors.dead_reckon.dead_reckon(ax, ay, az, t)¶

ttempt dead reckoning (estimating position) from accelerometer data.

ax : list or numpy array of floats: accelerometer x-axis data
ay : list or numpy array of floats: accelerometer y-axis data
az : list or numpy array of floats: accelerometer z-axis data
t : list or numpy array of floats: accelerometer time points

x : list or numpy array of floats: estimated position along x-axis
y : list or numpy array of floats: estimated position along y-axis
z : list or numpy array of floats: estimated position along z-axis
distance : float: estimated change in position

>>> from mhealthx.extractors.dead_reckon import dead_reckon
>>> from mhealthx.xio import read_accel_json
>>> #input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/accel_walking_outbound.json.items-6dc4a144-55c3-4e6d-982c-19c7a701ca243282023468470322798.tmp'
>>> input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/deviceMotion_walking_outbound.json.items-5981e0a8-6481-41c8-b589-fa207bfd2ab38771455825726024828.tmp'
>>> start = 150
>>> device_motion = True
>>> t, axyz, gxyz, uxyz, rxyz, sample_rate, duration = read_accel_json(input_file, start, device_motion)
>>> ax, ay, az = axyz
>>> x, y, z, distance = dead_reckon(ax, ay, az, t)

mhealthx.extractors.dead_reckon.position_from_velocity(vx, vy, vz, t)¶

Estimate position from velocity.

vx : list or numpy array of floats: estimated velocity along x-axis
vy : list or numpy array of floats: estimated velocity along y-axis
vz : list or numpy array of floats: estimated velocity along z-axis
t : list or numpy array of floats: accelerometer time points

x : list or numpy array of floats: estimated position along x-axis
y : list or numpy array of floats: estimated position along y-axis
z : list or numpy array of floats: estimated position along z-axis
distance : float: estimated change in position

>>> from mhealthx.extractors.dead_reckon import velocity_from_acceleration, position_from_velocity
>>> from mhealthx.xio import read_accel_json
>>> #input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/accel_walking_outbound.json.items-6dc4a144-55c3-4e6d-982c-19c7a701ca243282023468470322798.tmp'
>>> input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/deviceMotion_walking_outbound.json.items-5981e0a8-6481-41c8-b589-fa207bfd2ab38771455825726024828.tmp'
>>> #input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/deviceMotion_walking_outbound.json.items-a2ab9333-6d63-4676-977a-08591a5d837f5221783798792869048.tmp'
>>> start = 150
>>> device_motion = True
>>> t, axyz, gxyz, uxyz, rxyz, sample_rate, duration = read_accel_json(input_file, start, device_motion)
>>> ax, ay, az = axyz
>>> vx, vy, vz = velocity_from_acceleration(ax, ay, az, t)
>>> x, y, z, distance = position_from_velocity(vx, vy, vz, t)

mhealthx.extractors.dead_reckon.velocity_from_acceleration(ax, ay, az, t)¶

Estimate velocity from accelerometer readings.

ax : list or numpy array of floats: accelerometer x-axis data
ay : list or numpy array of floats: accelerometer y-axis data
az : list or numpy array of floats: accelerometer z-axis data
t : list or numpy array of floats: accelerometer time points

vx : list or numpy array of floats: estimated velocity along x-axis
vy : list or numpy array of floats: estimated velocity along y-axis
vz : list or numpy array of floats: estimated velocity along z-axis

>>> from mhealthx.extractors.dead_reckon import velocity_from_acceleration
>>> from mhealthx.xio import read_accel_json
>>> #input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/accel_walking_outbound.json.items-6dc4a144-55c3-4e6d-982c-19c7a701ca243282023468470322798.tmp'
>>> input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/deviceMotion_walking_outbound.json.items-5981e0a8-6481-41c8-b589-fa207bfd2ab38771455825726024828.tmp'
>>> #input_file = '/Users/arno/DriveWork/mhealthx/mpower_sample_data/deviceMotion_walking_outbound.json.items-a2ab9333-6d63-4676-977a-08591a5d837f5221783798792869048.tmp'
>>> start = 150
>>> device_motion = True
>>> t, axyz, gxyz, uxyz, rxyz, sample_rate, duration = read_accel_json(input_file, start, device_motion)
>>> ax, ay, az = axyz
>>> vx, vy, vz = velocity_from_acceleration(ax, ay, az, t)

extractors.dead_reckon¶

Module: extractors.dead_reckon¶

Functions¶

Module: `extractors.dead_reckon`¶