dcshift: Direct-Current shift removal

In emanuelhuber/RGPR: Ground-penetrating radar (GPR) data visualisation, processing and delineation

Direct-Current shift removal

Description

The direct-current offset (DC-shift) is estimated and removed from every trace individually. For a given trace, the DC-shift is estimated by a user supplied function applied on few trace samples, normally the samples before time-zero (e.g., the average of the samples before time-zero). Then, the DC-shift is substracted from the trace.

Usage

## S4 method for signature 'GPR'
dcshift(x, u = NULL, FUN = mean, ..., track = TRUE)

Arguments

x	[GPR class] An object of the class GPR.
u	[integer] Index of the trace samples used to evaluate for every trace the DC-shift. If u = NULL, the function takes for each trace 90% of the samples before time-zero (the number of samples can vary from trace to trace).
FUN	[function] A function to apply on the u trace samples (default is mean; alternatively, median could be of interest because it is more robust but slower to compute).
...	[ANY] Further arguments to be passed to FUN.

Details

The direct-current offset (or DC-shift) is a constant bias over time that slightly shifts the signal amplitude. The DC-shift is best observed on the trace samples recorded before the signal was emitted.

Modified slots

• data: DC-shift removed (data dimensions unchanged).

• proc: updated with function name and arguments.

Value

[GPR class] An object of the class GPR.

Examples

data("frenkeLine00")
x <- frenkeLine00
x1 <- dcshift(x, u = 1:100, FUN = median)
plot(x - x1)
x2 <- dcshift(x)
plot(x - x2)

emanuelhuber/RGPR documentation built on March 18, 2024, 8 p.m.