\name{osteo}
\alias{osteo}
\docType{data}
\title{
  Osteocyte Lacunae Data: Replicated Three-Dimensional Point Patterns
}
\description{
  These data give the three-dimensional locations of 
  osteocyte lacunae observed in rectangular volumes of
  solid bone using a confocal microscope.

  There were four samples of bone, and ten regions were mapped
  in each bone, yielding 40 spatial point patterns.
  The data can be regarded as replicated observations of a
  three-dimensional point process, nested within bone samples.
}
\usage{data(osteo)}
\format{
  A \code{\link[spatstat]{hyperframe}} with the following columns:

  \tabular{ll}{
    \code{id} \tab character string identifier of bone sample \cr
    \code{shortid} \tab last numeral in \code{id} \cr
    \code{brick} \tab serial number (1 to 10) of sampling volume within
    this bone sample \cr
    \code{pts} \tab three dimensional point pattern (class \code{pp3}) \cr
    \code{depth} \tab the depth of the brick in microns 
  }
}
\details{
  These data are three-dimensional point patterns
  representing the positions of \emph{osteocyte lacunae}, holes
  in bone which were occupied by osteocytes (bone-building cells) during life. 
  
  Observations were made on four different skulls of Macaque monkeys
  iusing a three-dimensional microscope.
  From each skull, observations were collected in 10 separate sampling volumes.
  In all, there are 40 three-dimensional point patterns in the dataset.
  
  The data were collected in 1984
  by A. Baddeley, A. Boyde, C.V. Howard and S. Reid
  (see references) using the tandem-scanning reflected light microscope
  (TSRLM) at University College London. This was one of the first
  optical confocal microscopes available.

  Each point pattern dataset gives the \eqn{(x,y,z)} coordinates  
  (in microns) of all points visible in a
  three-dimensional rectangular box (``brick'') of dimensions
  \eqn{81 \times 100 \times d}{81 * 100 * d} microns,
  where \eqn{d} varies.
  The \eqn{z} coordinate is depth into the bone
  (depth of the focal plane of the confocal microscope); the \eqn{(x,y)}
  plane is parallel to the exterior surface of the bone;
  the relative orientation of the \eqn{x} and \eqn{y} axes is not important.
  
  The bone samples were three intact skulls and one skull
  cap, all originally identified as belonging to the macaque monkey
  \emph{Macaca fascicularis}, from the collection of the
  Department of Anatomy, University of London. Later analysis
  (Baddeley et al, 1993) suggested that the skull cap, given here as
  the first animal, was a different subspecies, and this was confirmed by
  anatomical inspection.
}
\section{Sampling Procedure}{
  The following extract from Baddeley et al (1987)
  describes the sampling procedure.

  The parietal bones of three fully articulated adult Macaque monkey
    \emph{(Macaca fascicularis)} skulls from the collection of
    University College London were used. The right parietal bone was
    examined, in each case, approximately 1 cm lateral to the sagittal
    suture and 2 cm posterior to the coronal suture. The skulls were
    mounted on plasticine on a moving stage placed beneath the TSRLM.
    Immersion oil was applied and a \eqn{\times 60}{X 60}, NA 1.0 oil immersion
    objective lens (Lomo) was focussed at 10 microns below the cranial
    surface. The TV image was produced by a Panasonic WB 1850/B camera
    on a Sony PVM 90CE TV monitor.

    A graduated rectangular counting frame
    \eqn{90 \times 110}{90 * 110} mm (representing
    \eqn{82 \times 100}{82 * 100} microns in real units)
    was marked on a Perspex overlay
    and fixed to the screen. The area of tissue seen within the frame defined
    a subfield: a guard area of 10 mm width was visible on all sides of the 
    frame. Ten subfields were examined, arranged approximately in
    a rectangular grid pattern, with at least one field width separating
    each pair of fields. The initial field position was determined randomly
    by applying a randomly-generated coordinate shift to the moving stage.
    Subsequent fields were attained 
    using the coarse controls of the microscope stage, in accordance with 
    the rectangular grid pattern.

    For each subfield, the focal plane was racked down from its initial
    10 micron depth until all visible osteocyte lacunae had been examined.
    This depth \eqn{d} was recorded. The 3-dimensional sampling volume was
    therefore a rectangular box of dimensions
    \eqn{82 \times 100 \times d}{82 * 100 * d} microns,
    called a ``brick''.
    For each visible lacuna, the fine focus racking control was adjusted until
    maximum brightness was obtained. The depth of the focal plane was then
    recorded as the $z$ coordinate of the ``centre point''  of the
    lacuna. Without moving the focal plane, the \eqn{x} and \eqn{y}
    coordinates of
    the centre of the lacunar image were read off the graduated counting frame.
    This required a subjective judgement of the position of the centre of the
    2-dimensional image. Profiles were approximately elliptical and the centre 
    was considered to be well-defined. Accuracy of 
    the recording procedure was tested by independent repetition (by the
    same operator and by different operators) and found to be reproducible
    to plus or minus 2 mm on the screen.
  
    A lacuna was counted only if its \eqn{(x, y)} coordinates lay inside
    the \eqn{90 \times 110}{90 * 110} mm counting frame.
}
\source{
  Data were collected by \adrian.
}
\references{
  Baddeley, A.J., Howard, C.V, Boyde, A. and Reid, S.A. (1987)
  Three dimensional analysis of the spatial distribution of
  particles using the tandem-scanning reflected light microscope.
  \emph{Acta Stereologica} \bold{6} (supplement II) 87--100.

  Baddeley, A.J., Moyeed, R.A., Howard, C.V. and Boyde, A. (1993)
  Analysis of a three-dimensional point pattern
  with replication.
  \emph{Applied Statistics} \bold{42} (1993) 641--668.
  
  Howard, C.V. and Reid, S. and Baddeley, A.J. and Boyde, A. (1985)
  Unbiased estimation of particle density 
  in the tandem-scanning reflected light microscope.
  \emph{Journal of Microscopy} \bold{138} 203--212.
}
\examples{
  data(osteo)
  if(require(spatstat)) {
  osteo
  if(interactive()) {
    plot(osteo$pts[[1]], main="animal 1, brick 1")
    ape1 <- osteo[osteo$shortid==4, ]
    plot(ape1, tick.marks=FALSE)
    with(osteo, intensity(pts))
    plot(with(ape1, K3est(pts)))
  }
  }
}
\keyword{datasets}
