artifacts {accelerometry} | R Documentation |
Corrects abnormally high count values in accelerometer data by replacing such values with the average of neighboring count values. Returns integer vector despite the average calculation often producing a decimal; this follows the convention used in the NCI's SAS programs (http://riskfactor.cancer.gov/tools/nhanes_pam).
artifacts(counts, thresh, counts_classify = NULL)
counts |
Integer vector with accelerometer count values. |
thresh |
Integer value specifying the smallest count value that should be considered an artifact. |
counts_classify |
Integer vector with accelerometer count values to base artifact classification on, but not to adjust. Mainly included for triaxial data, where you might want to define artifacts based on vertical-axis counts but then actually adjust the triaxial sum or vector magnitude counts. |
Integer vector equivalent to counts
except where artifacts
were adjusted.
National Cancer Institute. Risk factor monitoring and methods: SAS programs for analyzing NHANES 2003-2004 accelerometer data. Available at: http://riskfactor.cancer.gov/tools/nhanes_pam. Accessed Aug. 19, 2018.
# Load accelerometer data for first 5 participants in NHANES 2003-2004
data(unidata)
# Get data from ID number 21007
counts.part3 <- unidata[unidata[, "seqn"] == 21007, "paxinten"]
# Replace counts > 10,000 with average of neighboring values
counts.part3.corrected <- artifacts(counts = counts.part3, thresh = 10000)