Index: trunk/doc/design/ippSRS.tex
===================================================================
--- trunk/doc/design/ippSRS.tex	(revision 2192)
+++ trunk/doc/design/ippSRS.tex	(revision 2241)
@@ -1,3 +1,3 @@
- %%% $Id: ippSRS.tex,v 1.11 2004-10-22 04:43:35 eugene Exp $
+ %%% $Id: ippSRS.tex,v 1.12 2004-10-29 22:00:08 eugene Exp $
 \documentclass[panstarrs,spec]{panstarrs}
 
@@ -6,5 +6,5 @@
 \subtitle{Software Requirements Specification}
 \shorttitle{IPP SRS}
-\author{Eugene Magnier, Paul A. Price, Josh Hoblitt}
+\author{Eugene A. Magnier, Paul A. Price, Josh Hoblitt}
 \audience{Pan-STARRS PMO}
 \group{Pan-STARRS Algorithm Group}
@@ -34,9 +34,11 @@
 \RevisionsStart
 % version     Date         Description
-DR.01 & 2003.01.01 & First draft  \\ \hline
-DR.02 & 2003.03.10 & Second draft \\ \hline
-DR.03 & 2003.04.13 & Most paragraphs fleshed out \\ \hline
-DR.04 & 2003.04.27 & Basic text frozen for internal review \\ \hline
-DR.05 & 2003.05.24 & Incorporating comments from internal review \\ \hline
+DR.01 & 2004.01.01 & First draft  \\ \hline
+DR.02 & 2004.03.10 & Second draft \\ \hline
+DR.03 & 2004.04.13 & Most paragraphs fleshed out \\ \hline
+DR.04 & 2004.04.27 & Basic text frozen for internal review \\ \hline
+DR.05 & 2004.05.24 & Incorporating comments from internal review \\ \hline
+DR.06 & 2004.08.06 & Revisions in prep of SRR \\ \hline
+DR.06 & 2004.10.22 & Revisions based on SRR \\ \hline
 \RevisionsEnd
 
@@ -580,50 +582,7 @@
 \subsubsection{Image Server}
 
-%% IPP Image Server T & F
-
-Image Server tasks and functions:
-
-\begin{itemize}
-
-\item The IPP Image Server stores images on a distributed collection
-  of computer disks.  Individual instances of a file are only required
-  to be stored on a single machine (striping across computers is not a
-  requirement).
-
-\item The IPP Image Server attempts to store an image on a specific
-  machine if requested by the user.
-
-\item If such a request cannot be honored (ie, the machine is down),
-  the IPP Image Server selects an appropriate machine and notifies the
-  requesting agent of the new location.
-
-\item The IPP Image Server stores multiple copies of each image upon
-  request, the number of copies specified independently for each file
-  by the user.
-
-\item The IPP Image Server maintains a record of all image copies
-  currently available in the repository.  This record includes at
-  least the image name, location (which machine), the image size, and
-  the state of the image (available, locked,
-  deleted).
-
-\item The IPP Image Server locks images in the repository on request.
-  Both read (shared) and write (exclusive) locks are provided.  A read
-  lock prevents write access to the file; a write lock prevents both
-  read and write access.  Access prevention may be advisory rather
-  than rigorously enforced.
-
-\item The IPP Image Server return the image location (the computer or
-  computers on which it resides) upon request.
-
-\item The IPP Image Server provides a specified image upon request.
-
-\item The IPP Image Server deletes images in the repository on
-  request.
-\end{itemize}
-
 %% IPP Image Server Requirements
 
-IPP Image Server requirements:
+IPP Image Server has the following requirements:
 
 \begin{enumerate}
@@ -697,95 +656,4 @@
 \end{center}
 \end{table}
-
-%% IPP AP DB T & F
-
-The purpose of the AP Database is:
-\begin{itemize}
-\item to enable the photometric calibration of images
-\item to enable the astrometric calibration of images
-\item to enable the construction of flat-field correction frames
-\item to enable the construction of a photometric calibration catalog
-\item to enable the construction of an astrometric calibration catalog
-\item to monitor the system photometry calibration parameters
-\item to monitor the system astrometry calibration parameters
-\item to perform the identification of single-occurance transients
-\end{itemize}
-
-The tasks and functions of the AP Database include:
-
-\begin{itemize}
-\item The AP Database accepts and stores individual detections and
-  collections of detections along with information about the image
-  which provided the detections.
-
-\item Detections are saved as one of several detection classes (P2,
-  P4$\Sigma$, P4$\Delta$, SS) and the AP Database stores the
-  appropriate parameters, listed in Table~\ref{APdetections}, for each
-  class.
-
-\item The AP Database identifies the image which provided the
-  detection, or in the case of external references, an identifier
-  specific to the reference source.
-
-\item The AP Database groups detections into objects on the basis of
-  positional coincidence and measures average parameters of those
-  objects.
-
-\item The AP Database stores parallax and proper motion parameters for
-  a subset of the average objects.
-
-\item The AP Database stores image and filter calibration information
-  necessary to convert between instrumental magnitudes and calibrated
-  magnitudes in standard systems.
-
-\item The AP Database performs at least the follow queries, with
-  constraints on the output based on at least time ranges, magnitude
-  limits, error limits:
-
- \begin{itemize}
- \item given $(RA,DEC)$ and a Radius, return all objects and/or
- detections in the region.
-
- \item given $(RA,DEC)_0$ to $(RA,DEC)_1$, return all objects and/or
-   detections in the region.
-
- \item given $(RA,DEC)$, return closest object.
-
- \item given object ID, return all detections.
-
- \item given detection, return source image data.
-
- \item given detection, return object.
-
- \item given $(RA,DEC)$, return all images overlapping coordinate.
-
- \item given $(RA,DEC)$ and a Radius, return all images overlapping region.
-
- \item given $(RA,DEC)_0$ to $(RA,DEC)_1$, return all images overlapping region.
-
- \item given detection instrumental magnitude, return derived
-   magnitudes based on calibration information.
-
- \item given a collection of detections in a filter, determine the
-   object average magnitude in that filter.
-
- \item given a collection of objects and detections, determine the
-   individual image zero-points.
-
- \item given a region, return all possible combinations of the object
-   or detection magnitudes $(M_1 - M_2)$.
-
- \item given a list of $(RA,DEC)$ entries, return all nearest objects.
-
- \item given a filter, telescope, or detector, return all calibration
-   terms and history.
-
- \item given a detection, return all non-detections from images which
-   overlapped the detection coordinates.
- \end{itemize}
-
-\item The AP Database shall accept detection IDs of moving objects and
-  label the detections with the identified object.
-\end{itemize}
 
 %% IPP AP DB Requirements
@@ -834,28 +702,4 @@
 \end{table}
 
-%% Metadata DB T & F
-
-The Metadata Database tasks and functions:
-
-\begin{itemize}
-\item The Metadata Database stores the classes of data listed in
-  Table~\ref{metadata}.  Thus, the Metadata Database stores and serves
-  metadata for all raw images, for processed images, for the
-  calibration images (both raw and master), for the extracted object
-  lists.  Metadata describing the environmental conditions at the
-  telescope is also stored and provided as needed.  
-
-\item The Metadata Database responds to simple queries which return
-  the data in the categories listed in Table~\ref{metadata} based on
-  the primary data key and with basic constraints of time ranges and
-  other simple conditional constraints.
-
-\item The Metadata database stores the configuration information with
-  restricted access so that only specific people may change the
-  information (eg, science parameters available to the science team;
-  software configuration parameters available to the system
-  maintainers).
-\end{itemize}
-
 %% Metadata DB Requirements
 
@@ -883,61 +727,4 @@
 \subsubsection{Controller}
 
-%% IPP Controller T & F
-
- IPP Controller tasks and functions:
-
-\begin{itemize}
-
-\item On startup, the IPP Controller attempts to establish
-  communication with all of its computers and set their state to be
-  {\tt alive} or {\tt dead} based on the success of the
-  connection.
-
-\item The IPP Controller detects computers which crash or stop
-  responding and set their state to {\tt dead}.
-
-\item The IPP Controller attempts to re-establish communication with
-  {\tt dead} computers.
-
-\item The IPP Controller accepts tasks from external users and
-  systems, which may specify a desired CPU (node) and priority in
-  addition to the task command.
-
-\item The IPP Controller attempts to run pending tasks on the desired
-  node, if available (not {\tt dead} or {\tt off}).
-
-\item If the node is unavailable, the IPP Controller attempts to run
-  the task on another node.
-
-\item If the node is available, the IPP Controller attempts to run a
-  given task only if no higher-priority tasks are available and no
-  task is currently being executed.
-
-\item The IPP Controller monitors the output from the task and writes
-  it to an associated log destination.
-
-\item The IPP Controller monitors the execution status of each task
-  currently executing on a node and performs the following actions:
-
-  \begin{itemize}
-  \item identify the task as successful if it has a valid exit status.
-  \item identify the task as unsuccessful if it has an error exit status.
-  \item identify the task as unattempted if the computer crashed.
-  \end{itemize}
-
-\item The IPP Controller accepts and performs the following external
-  commands:
-  \begin{itemize}
-  \item add a task to the pending task list.
-  \item delete a specific task from the pending task list.
-  \item return the current status of a specific task.
-  \item return a list of all pending and non-pending tasks.
-  \item set a specified computer state to {\tt off} or {\tt dead}.
-  \item restrict a specified CPU to a class of tasks.
-  \item halt execution of a specified task.
-  \item set the IPP Controller state to {\tt finish}, {\tt abort}, or {\tt stop}.
-  \end{itemize}
-\end{itemize}
-
 %% IPP Controller Requirements
 
@@ -963,30 +750,4 @@
 
 \subsubsection{Scheduler}
-
-%% IPP Scheduler T & F
-
-The IPP Scheduler tasks and functions:
-
-\begin{itemize}
-\item The IPP Scheduler sends the analysis tasks which it initiates to
-  the IPP Controller.
-
-\item All analysis tasks sent by the IPP Scheduler include a complete
-  UNIX command with necessary arguments, the priority of the task, and
-  optionally the desired processing node.
-
-\item When the IPP Scheduler is placed in the {\em paused state}, it
-  only initiates User-requested tasks.
-
-\item When the IPP Scheduler is placed in the {\em interactive state},
-  it initiates User-requested tasks as well as data transfer tasks.
-
-\item When the IPP Scheduler is placed in the {\em automatic state},
-  it initiates the most appropriate task based on the inputs and
-  dependency rules.
-
-\item The IPP Scheduler sends the exit status of the analysis tasks to
-  the appropriate destination as defined by the task dependency table.
-\end{itemize}
 
 %% IPP Scheduler Requirements
@@ -1078,28 +839,7 @@
 \subsubsection{Phase 1 : image processing preparation}
 
-Phase 1 is the image processing preparation stage.  The analysis is
-performed on a complete FPA.  At the end of this analysis, the FPA is
-ready to be analysed in detail in Phase 2.  The Phase 1 tasks and
-functions are:
-
-\begin{itemize}
-
-\item Extract FPA guide stars to determine astrometry across the full FPA
-
-\item If no guide stars are available, phase 1 must measure the pixel
-  coordinates of known bright stars expected in the field from the
-  image data.
-
-\item The total number of stars and size of the bright-star
-  acquisition box shall be a user-configurable parameter in the range
-  20 - 250.
-
-\item Calculate the Image cell / Sky cell overlaps for each image.
-  Sky cells which do not have sufficient science image overlap $< 5\%$
-  are excluded from the overlap table.
-
-\end{itemize}
-
-The Phase 1 requirements are:
+The Phase 1 analysis stage is performed on each science exposure (each
+complete FPA image) to calculate basic astrometric data needed by the
+later stages.  The Phase 1 requirements are:
 
 \begin{enumerate}
@@ -1123,5 +863,5 @@
 %% Phase 2
 \subsubsection{Phase 2 : image reduction}
-
+  
 Phase 2 is the detrend stage, in which each detector is separately
 processed to remove instrumental signatures.  The result of Phase 2 is
@@ -1129,68 +869,5 @@
 collection of objects detected in the image and characterized in a
 rudimentary way (star / non-stellar), and a measurement of the PSF
-across the detector.  
-
-The tasks and functions of Phase 2 are as follows:
-
-\begin{itemize}
-
-\item Convolve the flat-field and high-spatial-frequency fringe images
-  with the OT kernel.
-
-\item Mask ghosts of bright stars which introduce residual feature
-  more significant than 1\% of the background.
-
-\item Bias subtract the image.
-
-\item Correct each chip independently for non-linearity.
-
-\item Flat-field correct the image.
-
-\item Subtract a fit to the detector-dependent fringing pattern.
-
-\item Subtract a fit to the low-spatial frequency sky background.
-
-\item Identify `cosmic rays' on the basis of morphology.
-
-\item Perform (positive) object detection on the processed images,
-  down to a user-configured threshold, likely to be $\sim 20\sigma$.
-  The detection threshold may optionally be a function of the average
-  background flux or the local noise level.
-
-\item Measure the following object parameters:
-
-  \begin{itemize}
-  \item object centroid and position errors.
-  \item an extended object position ($x_g, y_g$).
-  \item instrumental PSF magnitude and error.
-  \item local background level and error.
-  \item second moments ($\sigma_{\rm min}, \sigma_{maj}$) of the object
-    and their covariance matrix.
-  \end{itemize}
-
-\item Perform minimal object classification to distinguish objects
-  which are consistent with a single PSF, objects which are
-  inconsistently large, objects which are inconsistently small, and
-  objects which are saturated.
-
-\item Match the detected objects with known astrometric reference
-  objects, including proper-motion compensation.
-
-\item Fit the reference and detected object coordinates to determine
-  astrometric parameters for the individual OTAs, including
-  polynomials of the coordinates up to 3rd order (user-specified
-  parameter).  The Cell astrometric parameters are not allowed to vary
-  in the fit, which uses outlier rejection to determine a robust
-  solution. 
-
-\item Extract subrasters (`postage stamps') surrounding a
-  user-specified list of coordinates from the flattened
-  images, to be saved in the IPP Image Server.
-
-\item measure the PSF variation as a function of detector position.
-
-\end{itemize}
-  
-The Phase 2 requirements are:
+across the detector.  The Phase 2 requirements are:
 
 \begin{enumerate}
@@ -1238,36 +915,6 @@
 reference catalogs to determine improved photometric and astrometric
 calibrations for the FPA as a whole, and to improve the measurement of
-the PSF and sky variations across the field.  The Phase 3 tasks and
-functions are as follows:
-
-\begin{itemize}
-
-\item Phase 3 uses the objects detected in Phase 2, matched with a
-  user-specified reference photometry catalog, to determine the image
-  photometric zero point and zero-point variations across the field.
-
-\item If zero-point variations are significant ($> 0.01$ mag
-  peak-to-peak), the zero-point variations are modeled with a
-  polynomial correction of order 3 or less.
-
-\item The photometric nature of the FPA image is categorized on the
-  basis of the zero-point consistency, the transparency compared with
-  recent long-term measurements in the filter, and the external
-  indicators of photometricity.
-
-\item Phase 3 uses the objects detected in Phase 2, matched with an
-  appropriate astrometric reference catalog, to improve the distortion
-  model used for the image.  The resulting astrometric accuracy is
-  consistent across the field to 30 mas, and is limited by the
-  astrometric reference catalog, (eg, 100 - 250 mas for
-  USNO-B1.0).
-
-\item The Phase 3 analysis modifies the background correction of Phase
-  2 based on the full-field statistics to achieve an accuracy of 1\%
-  of the background.
-
-\end{itemize}
-
-The Phase 3 requirements are:
+the PSF and sky variations across the field.  The Phase 3 requirements
+are:
 
 \begin{enumerate}
@@ -1310,110 +957,5 @@
 Phase 4 is the image combination stage, in which multiple images of
 the same portion of the sky are merged and confronted with the static
-sky image.  The Phase 4 tasks and functions are as follows:
-
-\begin{itemize}
-
-\item The Phase 4 analysis determines the corresponding set of image
-  pixels for a given sky cell.
-
-\item These pixels are extracted from the input images, using the
-  astrometric information for each OTA and Cell to determine the exact
-  overlaps.
-
-\item The Phase 4 analysis skips any sky cells with fewer than 5\% of
-  their pixels overlapping the input images.
-
-\item Pixels which have been extracted from the input images are
-  geometrically warped to match the corresponding pixels in the sky
-  image.  This transformation is based on the measured astrometric
-  solution for the input images relative to the reference catalog used
-  to generate the static sky image.  The warping may use a
-  locally-linear astrometric solution to speed the processing.
-  
-\item Phase 4 determines the appropriate photometry scaling factors
-  needed to combine the images photometrically.
-
-\item When multiple images are combined, the group of input pixels
-  which contribute to an output pixel are examined and pixels from the
-  group of images which are inconsistent with the ensemble (by an
-  amount defined by the user-configurable parameters) are identified
-  and flagged, though this outlier rejection shall be performed
-  optionally.
-
-\item The resulting collection of pixels is used to construct a single
-  output image, cleaned of the outliers.
-
-\item The cleaned, combined image is PSF matched with the static sky
-  image.
-
-\item The static sky image is subtracted from the stacked, cleaned
-  image, resulting in the difference image (P4$\Delta$ image)
-
-\item The Phase 4 analysis performs object detection on the difference
-  images.  All objects in the difference image above a user-configured
-  signficance threshold are detected, including both positive and
-  negative flux objects.  The detection threshold may optionally be a
-  function of the average background flux or the local noise
-  level.  The likely significance threshold is $\sim 3\sigma$.
-
-\item P4$\Delta$ objects have the following object parameters
-  measured:
-  \begin{itemize}
-  \item object centroid and position errors.
-  \item instrumental PSF magnitude and error.
-  \item local background level and error.
-  \item streak L, $\phi$, $\sigma_L$, $\sigma_\phi$.
-  \item second moments ($\sigma_{\rm min}, \sigma_{maj}$) and their covariance matrix.
-  \end{itemize}
-
-\item Minimal object classification is performed to distinguish
-  objects which are consistent with a single PSF, objects which are
-  inconsistent, and objects which are saturated.
-
-\item The pixels belonging to variable sources are masked in the
-  input image.
-
-\item A new, cleaned image is constructed from the masked input images
-  (P4$\Sigma$ image)
-
-\item Object detection is performed on the cleaned, summed image to a
-  user-configured significance threshold ($\sim 7\sigma$).  Only
-  positive flux object are considered.  The detection threshold may
-  optionally be a function of the average background flux or the local
-  noise level.
-
-\item P4$\Sigma$ objects have the following object parameters
-  measured:
-  \begin{itemize}
-  \item object centroid and position errors.
-  \item an extended object position ($x_g, y_g$).
-  \item instrumental PSF magnitude and error.
-  \item local background level and error.
-  \item second moments ($\sigma_{\rm min}, \sigma_{maj}$) and their
-    covariance matrix.
-  \item the Petrosian radius, magnitude, axis ratio, and angle.
-  \item the S\'ersic radius, magnitude, axis ratio, angle, and parameter $\nu$.
-  \end{itemize}
-
-\item Minimal object classification is performed to distinguish
-  objects which are consistent with a single PSF, objects which are
-  inconsistent, and objects which are saturated.
-
-\item Before the image is added to the static sky, it must pass Q/A
-  tests:
-  \begin{itemize}
-  \item the measured photometry scatter for the image must be less
-      than \tbr{1\%}.
-
-  \item the measured astrometry scatter for the image must be less
-  than \tbr{30 mas}.
-  \end{itemize}
-
-\item The final, cleaned input image is added to the static sky so
-  that an incrementally-deeper static sky image may be
-  made.
-\end{itemize}
-
-The Phase 4 requirements are:
+sky image.  The Phase 4 requirements are:
 
 \begin{enumerate}
@@ -1433,7 +975,7 @@
   time. \VER{TEST}{TLR:17}
 
-\item completeness?
-
-\item contamination?
+\item \tbd{completeness}
+
+\item \tbd{contamination}
 
 \end{enumerate}
@@ -1458,226 +1000,18 @@
 \end{enumerate}
 
-\subsubsection{Bias Image Creation}
-
-The Bias calibration stage constructs a master bias image from a
-collection of raw bias images.  The tasks and functions include:
+The calibrations consist of the following types of data:
 
 \begin{itemize}
-
-\item The Bias calibration stage corrects the input images based on
-  the overscan region, determined from either the header or from
-  metadata.
-
-\item The Bias calibration stage combines the input images using the
-  statistic specified by the user, selected from one of the following:
-  sample mean, median, and mode, robust mean, median, and mode, and
-  the clipped mean and median.
-
-\item The Bias calibration stage construct residual images, in which
-  the master bias is applied to the input images.
-
-\item Outlier residual images, those for which the residual bias and
-  variance in the bias image are excessive, are excluded from the
-  input image stack and the bias image reconstructed.
+\item Mask
+\item Bias 
+\item Dark
+\item Flat-field
+\item Fringe Pattern
+\item Low-spatial-frequency sky model 
+\item Flat-field correction image
+\item Non-linearity correction
+\item Telescope astrometry model
+\item Zero-point corrections
 \end{itemize}
-
-\subsubsection{Dark Image Creation}
-
-The Dark calibration stage shall construct a master dark image from a
-  collection of raw dark images.  The tasks and functions include:
-
-\begin{itemize}
-
-\item The Dark calibration stage raises an error if the input images
-  have exposure times which deviate by more than 2\%.
-
-\item The Dark calibration stage corrects the input dark images for
-  the bias.
-
-\item The Dark calibration stage combines the input images using the
-  statistic specified by the user, selected from one of the following:
-  sample mean, median, and mode, robust mean, median, and mode, and
-  the clipped mean and median.
-
-\item The Dark calibration stage constructs residual images, in which
-  the master dark is applied to the input images.
-
-\item Outlier residual images, those for which the residual level and
-  variance are excessive, are excluded from the input image stack and
-  the dark image reconstructed.
-\end{itemize}
-
-\subsubsection{Flat-field Image Creation}
-
-The Flat-field calibration stage constructs a master flat-field image
-from a collection of raw flat-field images.  The tasks and functions
-include:
-
-\begin{itemize}
-
-\item The Flat-field calibration stage accepts a group of images from
-  one of the following flat-field sources: dome, twilight,
-  night-sky.
-
-\item The flat-field calibration stage raises an error if the
-  input images in a single stack used more than one of the above
-  flat-field sources or multiple filters.
-
-\item The Flat-field calibration stage corrects the input flat-field
-  images for the bias and dark.
-
-\item The Flat-field calibration stage combines the input images using
-  the statistic specified by the user, selected from one of the
-  following: sample mean, median, and mode, robust mean, median, and
-  mode, and the clipped mean and median.
-
-\item The Flat-field calibration stage constructs residual images, in
-  which the master flat-field is applied to the input images.
-
-\item Outlier residual images, those for which the residual level and
-  variance are excessive ($> 0.1$\%, or 1.02 times the Poisson limit
-  of the flat-field image), are excluded from the input image stack
-  and the flat-field image reconstructed.
-\end{itemize}
-
-\subsubsection{Mask Image Creation}
-
-The Mask calibration stage constructs a bad-pixel mask from a stack of
-raw flat-field images and a master flat-field image.  The tasks and
-functions include:
-
-\begin{itemize}
-
-\item The Mask calibration stage masks the pixels which are
-  inconsistent in the input flats by more than 1\%, given sufficient
-  signal-to-noise in the input flats.
-
-\item The Mask calibration stage mask the pixels which are
-  consistently low or high in the input flats by more than a factor of
-  3 beyond the typical pixel.
-
-\item The Mask calibration stage masks the pixels identified in a
-  table of bad pixels generated externally to the calibration stage.
-
-\item The Mask calibration stage uses multiple bit values to identify
-  the different types of masked pixels.
-
-\item The Mask calibration stage raises an error if the input images
-  generate too many bad pixels in the mask.
-\end{itemize}
-
-\subsubsection{Fringe-frame Creation}
-
-The Fringe-frame Creation calibration stage constructs a master fringe
-frame from a stack of raw night-time sky images or from a stack of
-dome fringe frames.  The tasks and functions include:
-
-\begin{itemize}
-
-\item The Fringe-frame Creation calibration stage raises an error if
-  the input stack consists is images generated with more than one type
-  of fringe source or with multiple filters.
-
-\item The Fringe-frame Creation calibration stage flattens the input
-  images to remove the pixel-to-pixel sensitivity variations of the
-  detector.
-
-\item The Fringe-frame Creation calibration stage measures the fringe
-  amplitude on the input fringe images.
-
-\item The Fringe-frame Creation calibration stage scales the input
-  fringe images based on the fringe amplitude.
-
-\item The Fringe-frame Creation calibration stage combines the scaled
-  input images using the statistic specified by the user, selected
-  from one of the following: sample mean, median, and mode, robust
-  mean, median, and mode, and the clipped mean and median.
-
-\item The Fringe-frame Creation calibration stage constructs residual
-  images, in which the master fringe image is applied to the input
-  images, along with all necessary preceding calibration images.
-
-\item The Fringe-frame Creation calibration stage measures the
-  residual fringe amplitude on the residual images.
-\end{itemize}
-
-\subsubsection{Low-spatial-frequency Sky Models}
-
-The Sky Model calibration stage constructs a sky model image set from
-a stack of raw night-time sky images.
-
-\subsubsection{Flat-field correction Frame Creation}
-
-The Flat-field correction calibration stage constructs a flat-field
-correction image from dithered observations of a stellar field.  The
-tasks and functions include:
-
-\begin{itemize}
-
-\item The Flat-field correction calibration stage constructs a
-  flat-field correction image from dithered observations of a stellar
-  field.
-
-\item The Flat-field correction calibration stage constructs a
-  flat-field correction image for each filter and camera
-  independently.
-
-\item The Flat-field correction calibration stage constructs a
-  correction image which makes the photometry of multiple observations
-  of the same stellar source consistent at different locations in the
-  focal plane.
-
-\item The Flat-field correction calibration stage constructs corrected
-  flat-field images using the measured correction.
-
-\item The Flat-field correction calibration stage determines the
-  consistency of the corrected flat-field images using the dithered
-  stellar field observations flattened with the corrected flat-field
-  image.
-\end{itemize}
-
-\subsubsection{Non-linearity correction}
-
-The Non-linear correction calibration stage constructs a correction
-model for low-level non-linearity effects in the detector.  The tasks
-and functions include:
-
-\begin{itemize}
-
-\item The Non-linear correction calibration stage constructs a
-  non-linear correction from a collection of images of a constant
-  source with varying exposure times.
-
-\item The Non-linear correction calibration stage construct a
-  non-linear correction which linearizes the detector fluxes
-  $<0.5\%$.
-
-\item The Non-linear correction calibration stage determines the
-  saturation regime, in which the non-linear correction is no longer
-  consistent to $<0.5\%$.
-\end{itemize}
-
-\subsubsection{Telescope Astrometry Parameters}
-
-\begin{itemize}
-\item The IPP Calibration system constructs static models of the
-  telescope astrometry parameters (e.g., distortion, detector warps)
-  once per week.
-
-\item The IPP Calibration system constructs static models of the
-  telescope astrometry parameters (e.g., distortion, detector warps)
-  with an accuracy to produce astrometry consistent to 30
-  milliarcsec.
-
-\item The IPP Calibration system monitors changes in the telescope
-  astrometry parameters and issue a warning if the parameters change
-  by more than 2\%.
-\end{itemize}
-
-\subsubsection{Zero-Point Monitoring}
-
-The IPP Calibration system determines telescope filter and camera
-zero-points on a nightly basis with an accuracy sufficient to
-determine photometry in the native filter systems to 5 millimags.
 
 \subsection{Modules}
@@ -1794,5 +1128,5 @@
 
 \item IPP Controller - Analysis Tasks.  The IPP Controller shall
-initiate the Analysis Tasks and monitor their output and exit
+ initiate the Analysis Tasks and monitor their output and exit
 status.\TASK
 
@@ -1835,5 +1169,5 @@
 
 The report, `The Pan-STARRS Image Processing Pipeline Computational
-Challange' (PSDC-4xx-xx) discusses the assumptions and measurements
+Challenge' (PSDC-400-006) discusses the assumptions and measurements
 made to determine the IPP computing requirements, for both the PS-1
 configuration and the PS-4 configuration, under multiple assumptions
