counts: counts In activityCounts: Generate ActiLife Counts

Description

Calculates ActiLife counts based on raw accelerometer data

Usage

 ```1 2``` ```counts(data, hertz = -1, x_axis = 2, y_axis = 3, z_axis = 4, time_column = -1, start_time = -1) ```

Arguments

 `data` Accelerometer data, Must have at least three columns. `hertz` Sampling frequency in Hz `x_axis` Indicates the column number which has the accel data for x direction, the default is 2 `y_axis` Indicates the column number which has the accel data for y direction, the default is 3 `z_axis` Indicates the column number which has the accel data for z direction, the default is 4 `time_column` Optional. Indicates the column number which has the date and time. The first row will be considered as the start time of the study. You can use the "start_time" argument to provide the start time explicitly. `start_time` Optional. Use this to define the start time of the experiment. You can use this argument if the data does not contain a time column.

Value

Returns a `data.table` with four columns:

Time

The start time of the measurement

x

the number of counts for X axis

y

the number of counts for Y axis

z

the number of counts for Z axis

sampleXYZ raw accelerometer data for testing `counts()` function.
sampleCounts counts calculated by a`ctivityCounts` and ActiLife
 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ```# for tha sampleXYZ dataset, sampling frequency is 100 Hz counts(data = sampleXYZ, hertz = 100) # when start time is given explicitly study_start_time <- "2017-08-22 12:30:10" counts(data = sampleXYZ, hertz = 100 , start_time = study_start_time) # the data has a time column, which is the first column counts(data = sampleXYZ, hertz = 100 , time_column = 1) # explicitly specify the X, Y and Z axis columns. counts(data = sampleXYZ, hertz = 100 , x_axis = 2,y_axis = 3, z_axis = 4) ```