beamUnspreadAdp.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/adp.R
\name{beamUnspreadAdp}
\alias{beamUnspreadAdp}
\title{Adjust ADP Signal for Spherical Spreading}
\usage{
beamUnspreadAdp(x, count2db = c(0.45, 0.45, 0.45, 0.45),
  asMatrix = FALSE, debug = getOption("oceDebug"))
}
\arguments{
\item{x}{An \code{adp} object, i.e. one inheriting from \code{\link{adp-class}}.}

\item{count2db}{a set of coefficients, one per beam, to convert from beam
echo intensity to decibels.}

\item{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).}

\item{debug}{an integer specifying whether debugging information is
to be printed during the processing. This is a general parameter that
is used by many \code{oce} functions. Generally, setting \code{debug=0}
turns off the printing, while higher values suggest that more information
be printed. If one function calls another, it usually reduces the value of
\code{debug} first, so that a user can often obtain deeper debugging
by specifying higher \code{debug} values.}
}
\value{
An object of \code{\link[base]{class}} \code{"adp"}.
}
\description{
Compensate ADP signal strength for spherical spreading.
}
\details{
First, beam echo intensity is converted from counts to decibels, by
multiplying by \code{count2db}.  Then, the signal decrease owing to
spherical spreading is compensated for by adding the term
\eqn{20\log10(r)}{20*log10(r)}, where \eqn{r}{r} is the distance from the
sensor head to the water from which scattering is occurring.  \eqn{r}{r} is
given by \code{x[["distance"]]}.
}
\examples{

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))

}
\references{
The coefficient to convert to decibels is a personal
communication.  The logarithmic term is explained in textbooks on acoustics,
optics, etc.
}
\seealso{
Other things related to adp data: \code{\link{[[,adp-method}},
  \code{\link{[[<-,adp-method}},
  \code{\link{ad2cpHeaderValue}}, \code{\link{adp-class}},
  \code{\link{adpEnsembleAverage}}, \code{\link{adp}},
  \code{\link{as.adp}}, \code{\link{beamName}},
  \code{\link{beamToXyzAdpAD2CP}},
  \code{\link{beamToXyzAdp}}, \code{\link{beamToXyzAdv}},
  \code{\link{beamToXyz}}, \code{\link{binmapAdp}},
  \code{\link{enuToOtherAdp}}, \code{\link{enuToOther}},
  \code{\link{handleFlags,adp-method}},
  \code{\link{is.ad2cp}}, \code{\link{plot,adp-method}},
  \code{\link{read.adp.ad2cp}},
  \code{\link{read.adp.nortek}},
  \code{\link{read.adp.rdi}},
  \code{\link{read.adp.sontek.serial}},
  \code{\link{read.adp.sontek}}, \code{\link{read.adp}},
  \code{\link{read.aquadoppHR}},
  \code{\link{read.aquadoppProfiler}},
  \code{\link{read.aquadopp}}, \code{\link{rotateAboutZ}},
  \code{\link{setFlags,adp-method}},
  \code{\link{subset,adp-method}},
  \code{\link{summary,adp-method}}, \code{\link{toEnuAdp}},
  \code{\link{toEnu}}, \code{\link{velocityStatistics}},
  \code{\link{xyzToEnuAdpAD2CP}},
  \code{\link{xyzToEnuAdp}}, \code{\link{xyzToEnu}}
}
\author{
Dan Kelley
}
\concept{things related to adp data}