Regarding point data imaging in GPR

[arnab-pal]

I have used 35 MHz frequency antennae in GPR. These antennae give point data, and the interval was fixed as 20 cm. Please help in making the final section of GPR in RGPR. As the section produced from readgpr shows discontinuity to make it continuous, I have tried to interpolatete the trace, but still I am unable to get satisfactory results.

[emanuelhuber]

Hello @arnab-pal

I am not sure if I understand your problem. You can send some figures or the data you want to interpolate. I will try to find a solution.
Best
Emanuel

[arnab-pal]

001.zip
I have attached one file where I am facing the problem. Please have a look. If you have any queries regarding the data, you can definitely ask for clarification.

Arnab

[arnab-pal]

Please check the data and help me to resolve the problem.

[emanuelhuber]

Hello @arnab-pal

I will try to allocate time for your issue next week.
Best,

Emanuel

[emanuelhuber]

Hello @arnab-pal

I checked your data. You have 99 traces (A-scan) and many of them are completely identical. That is why you have these sharp transitions between you bloc of identical traces.

plot(x, type = "wiggles", wsize = 0.5)

I would first try to understand the data (why do you have so many identical traces) before starting to do anything.

If you still want a kind of interpolation, you have to first extract the central traces of the bloc of identical traces and then interpolate them. Here below is an example.
I hope it helps.

Best,
Emanuel

if(!require("devtools")) install.packages("devtools")
devtools::install_github("emanuelhuber/RGPR")
library(RGPR)

x <- readGPR("001.DZT", Vmax = FALSE)  # Vmax = FALSE: return bit values

plot(x)

# group the identical traces together
v <- as.data.frame(t(x@data[10:11, ])) # I take 2 rows to build a data.frame
v[,2] <- 1:ncol(x)                     # trace number
grp <- by(v, v[,1], function(x) x)     # group the identical traces together
i <- sort(sapply(grp, function(x)      # for each group compute the index 
  round(mean(x[,2]))))                 # of the central trace

# plot only the central traces in wiggle mode (to see the traces)
plot(x[, i], type = "wiggles", wsize = 0.2)

# interpolate the central traces to traces regularly spaced (here all 1 cm)
x2 <- regInterpPos(x[, i], type = "cosine", dx= 0.01)
plot(x2)
 

Below the results of the interpolation: