beamUnspreadAdp {oce} | R Documentation |
Compensate ADP signal strength for spherical spreading.
beamUnspreadAdp(x, count2db = c(0.45, 0.45, 0.45, 0.45), asMatrix = FALSE, debug = getOption("oceDebug"))
x |
An |
count2db |
a set of coefficients, one per beam, to convert from beam echo intensity to decibels. |
asMatrix |
a boolean that indicates whether to return a numeric matrix, as opposed to returning an updated object (in which the matrix is cast to a raw value). |
debug |
an integer specifying whether debugging information is
to be printed during the processing. This is a general parameter that
is used by many |
First, beam echo intensity is converted from counts to decibels, by
multiplying by count2db
. Then, the signal decrease owing to
spherical spreading is compensated for by adding the term
20*log10(r), where r is the distance from the
sensor head to the water from which scattering is occuring. r is
given by x[["distance"]]
.
An object of class
"adp"
.
Dan Kelley
The coefficient to convert to decibels is a personal communication. The logarithmic term is explained in textbooks on acoustics, optics, etc.
Other things related to adp
data: [[,adp-method
,
[[<-,adp-method
, adp-class
,
adpEnsembleAverage
, adp
,
as.adp
, beamName
,
beamToXyzAdp
, beamToXyzAdv
,
beamToXyz
, binmapAdp
,
enuToOtherAdp
, enuToOther
,
plot,adp-method
, read.ad2cp
,
read.adp.nortek
,
read.adp.rdi
,
read.adp.sontek.serial
,
read.adp.sontek
, read.adp
,
read.aquadoppHR
,
read.aquadoppProfiler
,
read.aquadopp
,
subset,adp-method
,
summary,adp-method
, toEnuAdp
,
toEnu
, velocityStatistics
,
xyzToEnuAdp
, xyzToEnu
library(oce) data(adp) plot(adp, which=5) # beam 1 echo intensity adp.att <- beamUnspreadAdp(adp) plot(adp.att, which=5) # beam 1 echo intensity ## Profiles par(mar=c(4, 4, 1, 1)) a <- adp[["a", "numeric"]] # second arg yields matrix return value distance <- adp[["distance"]] plot(apply(a,2,mean), distance, type='l', xlim=c(0,256)) lines(apply(a,2,median), distance, type='l',col='red') legend("topright",lwd=1,col=c("black","red"),legend=c("original","attenuated")) ## Image plot(adp.att, which="amplitude",col=oce.colorsJet(100))