IPP Software Navigation Tools IPP Links Communication Pan-STARRS Links

Ignore:
Timestamp:
Oct 29, 2004, 12:01:49 PM (22 years ago)
Author:
eugene
Message:

updated PSDC numbers

File:
1 edited

Legend:

Unmodified
Added
Removed
  • trunk/doc/design/ippSRS.tex

    r2192 r2241  
    1  %%% $Id: ippSRS.tex,v 1.11 2004-10-22 04:43:35 eugene Exp $
     1 %%% $Id: ippSRS.tex,v 1.12 2004-10-29 22:00:08 eugene Exp $
    22\documentclass[panstarrs,spec]{panstarrs}
    33
     
    66\subtitle{Software Requirements Specification}
    77\shorttitle{IPP SRS}
    8 \author{Eugene Magnier, Paul A. Price, Josh Hoblitt}
     8\author{Eugene A. Magnier, Paul A. Price, Josh Hoblitt}
    99\audience{Pan-STARRS PMO}
    1010\group{Pan-STARRS Algorithm Group}
     
    3434\RevisionsStart
    3535% version     Date         Description
    36 DR.01 & 2003.01.01 & First draft  \\ \hline
    37 DR.02 & 2003.03.10 & Second draft \\ \hline
    38 DR.03 & 2003.04.13 & Most paragraphs fleshed out \\ \hline
    39 DR.04 & 2003.04.27 & Basic text frozen for internal review \\ \hline
    40 DR.05 & 2003.05.24 & Incorporating comments from internal review \\ \hline
     36DR.01 & 2004.01.01 & First draft  \\ \hline
     37DR.02 & 2004.03.10 & Second draft \\ \hline
     38DR.03 & 2004.04.13 & Most paragraphs fleshed out \\ \hline
     39DR.04 & 2004.04.27 & Basic text frozen for internal review \\ \hline
     40DR.05 & 2004.05.24 & Incorporating comments from internal review \\ \hline
     41DR.06 & 2004.08.06 & Revisions in prep of SRR \\ \hline
     42DR.06 & 2004.10.22 & Revisions based on SRR \\ \hline
    4143\RevisionsEnd
    4244
     
    580582\subsubsection{Image Server}
    581583
    582 %% IPP Image Server T & F
    583 
    584 Image Server tasks and functions:
    585 
    586 \begin{itemize}
    587 
    588 \item The IPP Image Server stores images on a distributed collection
    589   of computer disks.  Individual instances of a file are only required
    590   to be stored on a single machine (striping across computers is not a
    591   requirement).
    592 
    593 \item The IPP Image Server attempts to store an image on a specific
    594   machine if requested by the user.
    595 
    596 \item If such a request cannot be honored (ie, the machine is down),
    597   the IPP Image Server selects an appropriate machine and notifies the
    598   requesting agent of the new location.
    599 
    600 \item The IPP Image Server stores multiple copies of each image upon
    601   request, the number of copies specified independently for each file
    602   by the user.
    603 
    604 \item The IPP Image Server maintains a record of all image copies
    605   currently available in the repository.  This record includes at
    606   least the image name, location (which machine), the image size, and
    607   the state of the image (available, locked,
    608   deleted).
    609 
    610 \item The IPP Image Server locks images in the repository on request.
    611   Both read (shared) and write (exclusive) locks are provided.  A read
    612   lock prevents write access to the file; a write lock prevents both
    613   read and write access.  Access prevention may be advisory rather
    614   than rigorously enforced.
    615 
    616 \item The IPP Image Server return the image location (the computer or
    617   computers on which it resides) upon request.
    618 
    619 \item The IPP Image Server provides a specified image upon request.
    620 
    621 \item The IPP Image Server deletes images in the repository on
    622   request.
    623 \end{itemize}
    624 
    625584%% IPP Image Server Requirements
    626585
    627 IPP Image Server requirements:
     586IPP Image Server has the following requirements:
    628587
    629588\begin{enumerate}
     
    697656\end{center}
    698657\end{table}
    699 
    700 %% IPP AP DB T & F
    701 
    702 The purpose of the AP Database is:
    703 \begin{itemize}
    704 \item to enable the photometric calibration of images
    705 \item to enable the astrometric calibration of images
    706 \item to enable the construction of flat-field correction frames
    707 \item to enable the construction of a photometric calibration catalog
    708 \item to enable the construction of an astrometric calibration catalog
    709 \item to monitor the system photometry calibration parameters
    710 \item to monitor the system astrometry calibration parameters
    711 \item to perform the identification of single-occurance transients
    712 \end{itemize}
    713 
    714 The tasks and functions of the AP Database include:
    715 
    716 \begin{itemize}
    717 \item The AP Database accepts and stores individual detections and
    718   collections of detections along with information about the image
    719   which provided the detections.
    720 
    721 \item Detections are saved as one of several detection classes (P2,
    722   P4$\Sigma$, P4$\Delta$, SS) and the AP Database stores the
    723   appropriate parameters, listed in Table~\ref{APdetections}, for each
    724   class.
    725 
    726 \item The AP Database identifies the image which provided the
    727   detection, or in the case of external references, an identifier
    728   specific to the reference source.
    729 
    730 \item The AP Database groups detections into objects on the basis of
    731   positional coincidence and measures average parameters of those
    732   objects.
    733 
    734 \item The AP Database stores parallax and proper motion parameters for
    735   a subset of the average objects.
    736 
    737 \item The AP Database stores image and filter calibration information
    738   necessary to convert between instrumental magnitudes and calibrated
    739   magnitudes in standard systems.
    740 
    741 \item The AP Database performs at least the follow queries, with
    742   constraints on the output based on at least time ranges, magnitude
    743   limits, error limits:
    744 
    745  \begin{itemize}
    746  \item given $(RA,DEC)$ and a Radius, return all objects and/or
    747  detections in the region.
    748 
    749  \item given $(RA,DEC)_0$ to $(RA,DEC)_1$, return all objects and/or
    750    detections in the region.
    751 
    752  \item given $(RA,DEC)$, return closest object.
    753 
    754  \item given object ID, return all detections.
    755 
    756  \item given detection, return source image data.
    757 
    758  \item given detection, return object.
    759 
    760  \item given $(RA,DEC)$, return all images overlapping coordinate.
    761 
    762  \item given $(RA,DEC)$ and a Radius, return all images overlapping region.
    763 
    764  \item given $(RA,DEC)_0$ to $(RA,DEC)_1$, return all images overlapping region.
    765 
    766  \item given detection instrumental magnitude, return derived
    767    magnitudes based on calibration information.
    768 
    769  \item given a collection of detections in a filter, determine the
    770    object average magnitude in that filter.
    771 
    772  \item given a collection of objects and detections, determine the
    773    individual image zero-points.
    774 
    775  \item given a region, return all possible combinations of the object
    776    or detection magnitudes $(M_1 - M_2)$.
    777 
    778  \item given a list of $(RA,DEC)$ entries, return all nearest objects.
    779 
    780  \item given a filter, telescope, or detector, return all calibration
    781    terms and history.
    782 
    783  \item given a detection, return all non-detections from images which
    784    overlapped the detection coordinates.
    785  \end{itemize}
    786 
    787 \item The AP Database shall accept detection IDs of moving objects and
    788   label the detections with the identified object.
    789 \end{itemize}
    790658
    791659%% IPP AP DB Requirements
     
    834702\end{table}
    835703
    836 %% Metadata DB T & F
    837 
    838 The Metadata Database tasks and functions:
    839 
    840 \begin{itemize}
    841 \item The Metadata Database stores the classes of data listed in
    842   Table~\ref{metadata}.  Thus, the Metadata Database stores and serves
    843   metadata for all raw images, for processed images, for the
    844   calibration images (both raw and master), for the extracted object
    845   lists.  Metadata describing the environmental conditions at the
    846   telescope is also stored and provided as needed. 
    847 
    848 \item The Metadata Database responds to simple queries which return
    849   the data in the categories listed in Table~\ref{metadata} based on
    850   the primary data key and with basic constraints of time ranges and
    851   other simple conditional constraints.
    852 
    853 \item The Metadata database stores the configuration information with
    854   restricted access so that only specific people may change the
    855   information (eg, science parameters available to the science team;
    856   software configuration parameters available to the system
    857   maintainers).
    858 \end{itemize}
    859 
    860704%% Metadata DB Requirements
    861705
     
    883727\subsubsection{Controller}
    884728
    885 %% IPP Controller T & F
    886 
    887  IPP Controller tasks and functions:
    888 
    889 \begin{itemize}
    890 
    891 \item On startup, the IPP Controller attempts to establish
    892   communication with all of its computers and set their state to be
    893   {\tt alive} or {\tt dead} based on the success of the
    894   connection.
    895 
    896 \item The IPP Controller detects computers which crash or stop
    897   responding and set their state to {\tt dead}.
    898 
    899 \item The IPP Controller attempts to re-establish communication with
    900   {\tt dead} computers.
    901 
    902 \item The IPP Controller accepts tasks from external users and
    903   systems, which may specify a desired CPU (node) and priority in
    904   addition to the task command.
    905 
    906 \item The IPP Controller attempts to run pending tasks on the desired
    907   node, if available (not {\tt dead} or {\tt off}).
    908 
    909 \item If the node is unavailable, the IPP Controller attempts to run
    910   the task on another node.
    911 
    912 \item If the node is available, the IPP Controller attempts to run a
    913   given task only if no higher-priority tasks are available and no
    914   task is currently being executed.
    915 
    916 \item The IPP Controller monitors the output from the task and writes
    917   it to an associated log destination.
    918 
    919 \item The IPP Controller monitors the execution status of each task
    920   currently executing on a node and performs the following actions:
    921 
    922   \begin{itemize}
    923   \item identify the task as successful if it has a valid exit status.
    924   \item identify the task as unsuccessful if it has an error exit status.
    925   \item identify the task as unattempted if the computer crashed.
    926   \end{itemize}
    927 
    928 \item The IPP Controller accepts and performs the following external
    929   commands:
    930   \begin{itemize}
    931   \item add a task to the pending task list.
    932   \item delete a specific task from the pending task list.
    933   \item return the current status of a specific task.
    934   \item return a list of all pending and non-pending tasks.
    935   \item set a specified computer state to {\tt off} or {\tt dead}.
    936   \item restrict a specified CPU to a class of tasks.
    937   \item halt execution of a specified task.
    938   \item set the IPP Controller state to {\tt finish}, {\tt abort}, or {\tt stop}.
    939   \end{itemize}
    940 \end{itemize}
    941 
    942729%% IPP Controller Requirements
    943730
     
    963750
    964751\subsubsection{Scheduler}
    965 
    966 %% IPP Scheduler T & F
    967 
    968 The IPP Scheduler tasks and functions:
    969 
    970 \begin{itemize}
    971 \item The IPP Scheduler sends the analysis tasks which it initiates to
    972   the IPP Controller.
    973 
    974 \item All analysis tasks sent by the IPP Scheduler include a complete
    975   UNIX command with necessary arguments, the priority of the task, and
    976   optionally the desired processing node.
    977 
    978 \item When the IPP Scheduler is placed in the {\em paused state}, it
    979   only initiates User-requested tasks.
    980 
    981 \item When the IPP Scheduler is placed in the {\em interactive state},
    982   it initiates User-requested tasks as well as data transfer tasks.
    983 
    984 \item When the IPP Scheduler is placed in the {\em automatic state},
    985   it initiates the most appropriate task based on the inputs and
    986   dependency rules.
    987 
    988 \item The IPP Scheduler sends the exit status of the analysis tasks to
    989   the appropriate destination as defined by the task dependency table.
    990 \end{itemize}
    991752
    992753%% IPP Scheduler Requirements
     
    1078839\subsubsection{Phase 1 : image processing preparation}
    1079840
    1080 Phase 1 is the image processing preparation stage.  The analysis is
    1081 performed on a complete FPA.  At the end of this analysis, the FPA is
    1082 ready to be analysed in detail in Phase 2.  The Phase 1 tasks and
    1083 functions are:
    1084 
    1085 \begin{itemize}
    1086 
    1087 \item Extract FPA guide stars to determine astrometry across the full FPA
    1088 
    1089 \item If no guide stars are available, phase 1 must measure the pixel
    1090   coordinates of known bright stars expected in the field from the
    1091   image data.
    1092 
    1093 \item The total number of stars and size of the bright-star
    1094   acquisition box shall be a user-configurable parameter in the range
    1095   20 - 250.
    1096 
    1097 \item Calculate the Image cell / Sky cell overlaps for each image.
    1098   Sky cells which do not have sufficient science image overlap $< 5\%$
    1099   are excluded from the overlap table.
    1100 
    1101 \end{itemize}
    1102 
    1103 The Phase 1 requirements are:
     841The Phase 1 analysis stage is performed on each science exposure (each
     842complete FPA image) to calculate basic astrometric data needed by the
     843later stages.  The Phase 1 requirements are:
    1104844
    1105845\begin{enumerate}
     
    1123863%% Phase 2
    1124864\subsubsection{Phase 2 : image reduction}
    1125 
     865 
    1126866Phase 2 is the detrend stage, in which each detector is separately
    1127867processed to remove instrumental signatures.  The result of Phase 2 is
     
    1129869collection of objects detected in the image and characterized in a
    1130870rudimentary way (star / non-stellar), and a measurement of the PSF
    1131 across the detector. 
    1132 
    1133 The tasks and functions of Phase 2 are as follows:
    1134 
    1135 \begin{itemize}
    1136 
    1137 \item Convolve the flat-field and high-spatial-frequency fringe images
    1138   with the OT kernel.
    1139 
    1140 \item Mask ghosts of bright stars which introduce residual feature
    1141   more significant than 1\% of the background.
    1142 
    1143 \item Bias subtract the image.
    1144 
    1145 \item Correct each chip independently for non-linearity.
    1146 
    1147 \item Flat-field correct the image.
    1148 
    1149 \item Subtract a fit to the detector-dependent fringing pattern.
    1150 
    1151 \item Subtract a fit to the low-spatial frequency sky background.
    1152 
    1153 \item Identify `cosmic rays' on the basis of morphology.
    1154 
    1155 \item Perform (positive) object detection on the processed images,
    1156   down to a user-configured threshold, likely to be $\sim 20\sigma$.
    1157   The detection threshold may optionally be a function of the average
    1158   background flux or the local noise level.
    1159 
    1160 \item Measure the following object parameters:
    1161 
    1162   \begin{itemize}
    1163   \item object centroid and position errors.
    1164   \item an extended object position ($x_g, y_g$).
    1165   \item instrumental PSF magnitude and error.
    1166   \item local background level and error.
    1167   \item second moments ($\sigma_{\rm min}, \sigma_{maj}$) of the object
    1168     and their covariance matrix.
    1169   \end{itemize}
    1170 
    1171 \item Perform minimal object classification to distinguish objects
    1172   which are consistent with a single PSF, objects which are
    1173   inconsistently large, objects which are inconsistently small, and
    1174   objects which are saturated.
    1175 
    1176 \item Match the detected objects with known astrometric reference
    1177   objects, including proper-motion compensation.
    1178 
    1179 \item Fit the reference and detected object coordinates to determine
    1180   astrometric parameters for the individual OTAs, including
    1181   polynomials of the coordinates up to 3rd order (user-specified
    1182   parameter).  The Cell astrometric parameters are not allowed to vary
    1183   in the fit, which uses outlier rejection to determine a robust
    1184   solution.
    1185 
    1186 \item Extract subrasters (`postage stamps') surrounding a
    1187   user-specified list of coordinates from the flattened
    1188   images, to be saved in the IPP Image Server.
    1189 
    1190 \item measure the PSF variation as a function of detector position.
    1191 
    1192 \end{itemize}
    1193  
    1194 The Phase 2 requirements are:
     871across the detector.  The Phase 2 requirements are:
    1195872
    1196873\begin{enumerate}
     
    1238915reference catalogs to determine improved photometric and astrometric
    1239916calibrations for the FPA as a whole, and to improve the measurement of
    1240 the PSF and sky variations across the field.  The Phase 3 tasks and
    1241 functions are as follows:
    1242 
    1243 \begin{itemize}
    1244 
    1245 \item Phase 3 uses the objects detected in Phase 2, matched with a
    1246   user-specified reference photometry catalog, to determine the image
    1247   photometric zero point and zero-point variations across the field.
    1248 
    1249 \item If zero-point variations are significant ($> 0.01$ mag
    1250   peak-to-peak), the zero-point variations are modeled with a
    1251   polynomial correction of order 3 or less.
    1252 
    1253 \item The photometric nature of the FPA image is categorized on the
    1254   basis of the zero-point consistency, the transparency compared with
    1255   recent long-term measurements in the filter, and the external
    1256   indicators of photometricity.
    1257 
    1258 \item Phase 3 uses the objects detected in Phase 2, matched with an
    1259   appropriate astrometric reference catalog, to improve the distortion
    1260   model used for the image.  The resulting astrometric accuracy is
    1261   consistent across the field to 30 mas, and is limited by the
    1262   astrometric reference catalog, (eg, 100 - 250 mas for
    1263   USNO-B1.0).
    1264 
    1265 \item The Phase 3 analysis modifies the background correction of Phase
    1266   2 based on the full-field statistics to achieve an accuracy of 1\%
    1267   of the background.
    1268 
    1269 \end{itemize}
    1270 
    1271 The Phase 3 requirements are:
     917the PSF and sky variations across the field.  The Phase 3 requirements
     918are:
    1272919
    1273920\begin{enumerate}
     
    1310957Phase 4 is the image combination stage, in which multiple images of
    1311958the same portion of the sky are merged and confronted with the static
    1312 sky image.  The Phase 4 tasks and functions are as follows:
    1313 
    1314 \begin{itemize}
    1315 
    1316 \item The Phase 4 analysis determines the corresponding set of image
    1317   pixels for a given sky cell.
    1318 
    1319 \item These pixels are extracted from the input images, using the
    1320   astrometric information for each OTA and Cell to determine the exact
    1321   overlaps.
    1322 
    1323 \item The Phase 4 analysis skips any sky cells with fewer than 5\% of
    1324   their pixels overlapping the input images.
    1325 
    1326 \item Pixels which have been extracted from the input images are
    1327   geometrically warped to match the corresponding pixels in the sky
    1328   image.  This transformation is based on the measured astrometric
    1329   solution for the input images relative to the reference catalog used
    1330   to generate the static sky image.  The warping may use a
    1331   locally-linear astrometric solution to speed the processing.
    1332  
    1333 \item Phase 4 determines the appropriate photometry scaling factors
    1334   needed to combine the images photometrically.
    1335 
    1336 \item When multiple images are combined, the group of input pixels
    1337   which contribute to an output pixel are examined and pixels from the
    1338   group of images which are inconsistent with the ensemble (by an
    1339   amount defined by the user-configurable parameters) are identified
    1340   and flagged, though this outlier rejection shall be performed
    1341   optionally.
    1342 
    1343 \item The resulting collection of pixels is used to construct a single
    1344   output image, cleaned of the outliers.
    1345 
    1346 \item The cleaned, combined image is PSF matched with the static sky
    1347   image.
    1348 
    1349 \item The static sky image is subtracted from the stacked, cleaned
    1350   image, resulting in the difference image (P4$\Delta$ image)
    1351 
    1352 \item The Phase 4 analysis performs object detection on the difference
    1353   images.  All objects in the difference image above a user-configured
    1354   signficance threshold are detected, including both positive and
    1355   negative flux objects.  The detection threshold may optionally be a
    1356   function of the average background flux or the local noise
    1357   level.  The likely significance threshold is $\sim 3\sigma$.
    1358 
    1359 \item P4$\Delta$ objects have the following object parameters
    1360   measured:
    1361   \begin{itemize}
    1362   \item object centroid and position errors.
    1363   \item instrumental PSF magnitude and error.
    1364   \item local background level and error.
    1365   \item streak L, $\phi$, $\sigma_L$, $\sigma_\phi$.
    1366   \item second moments ($\sigma_{\rm min}, \sigma_{maj}$) and their covariance matrix.
    1367   \end{itemize}
    1368 
    1369 \item Minimal object classification is performed to distinguish
    1370   objects which are consistent with a single PSF, objects which are
    1371   inconsistent, and objects which are saturated.
    1372 
    1373 \item The pixels belonging to variable sources are masked in the
    1374   input image.
    1375 
    1376 \item A new, cleaned image is constructed from the masked input images
    1377   (P4$\Sigma$ image)
    1378 
    1379 \item Object detection is performed on the cleaned, summed image to a
    1380   user-configured significance threshold ($\sim 7\sigma$).  Only
    1381   positive flux object are considered.  The detection threshold may
    1382   optionally be a function of the average background flux or the local
    1383   noise level.
    1384 
    1385 \item P4$\Sigma$ objects have the following object parameters
    1386   measured:
    1387   \begin{itemize}
    1388   \item object centroid and position errors.
    1389   \item an extended object position ($x_g, y_g$).
    1390   \item instrumental PSF magnitude and error.
    1391   \item local background level and error.
    1392   \item second moments ($\sigma_{\rm min}, \sigma_{maj}$) and their
    1393     covariance matrix.
    1394   \item the Petrosian radius, magnitude, axis ratio, and angle.
    1395   \item the S\'ersic radius, magnitude, axis ratio, angle, and parameter $\nu$.
    1396   \end{itemize}
    1397 
    1398 \item Minimal object classification is performed to distinguish
    1399   objects which are consistent with a single PSF, objects which are
    1400   inconsistent, and objects which are saturated.
    1401 
    1402 \item Before the image is added to the static sky, it must pass Q/A
    1403   tests:
    1404   \begin{itemize}
    1405   \item the measured photometry scatter for the image must be less
    1406       than \tbr{1\%}.
    1407 
    1408   \item the measured astrometry scatter for the image must be less
    1409   than \tbr{30 mas}.
    1410   \end{itemize}
    1411 
    1412 \item The final, cleaned input image is added to the static sky so
    1413   that an incrementally-deeper static sky image may be
    1414   made.
    1415 \end{itemize}
    1416 
    1417 The Phase 4 requirements are:
     959sky image.  The Phase 4 requirements are:
    1418960
    1419961\begin{enumerate}
     
    1433975  time. \VER{TEST}{TLR:17}
    1434976
    1435 \item completeness?
    1436 
    1437 \item contamination?
     977\item \tbd{completeness}
     978
     979\item \tbd{contamination}
    1438980
    1439981\end{enumerate}
     
    14581000\end{enumerate}
    14591001
    1460 \subsubsection{Bias Image Creation}
    1461 
    1462 The Bias calibration stage constructs a master bias image from a
    1463 collection of raw bias images.  The tasks and functions include:
     1002The calibrations consist of the following types of data:
    14641003
    14651004\begin{itemize}
    1466 
    1467 \item The Bias calibration stage corrects the input images based on
    1468   the overscan region, determined from either the header or from
    1469   metadata.
    1470 
    1471 \item The Bias calibration stage combines the input images using the
    1472   statistic specified by the user, selected from one of the following:
    1473   sample mean, median, and mode, robust mean, median, and mode, and
    1474   the clipped mean and median.
    1475 
    1476 \item The Bias calibration stage construct residual images, in which
    1477   the master bias is applied to the input images.
    1478 
    1479 \item Outlier residual images, those for which the residual bias and
    1480   variance in the bias image are excessive, are excluded from the
    1481   input image stack and the bias image reconstructed.
     1005\item Mask
     1006\item Bias
     1007\item Dark
     1008\item Flat-field
     1009\item Fringe Pattern
     1010\item Low-spatial-frequency sky model
     1011\item Flat-field correction image
     1012\item Non-linearity correction
     1013\item Telescope astrometry model
     1014\item Zero-point corrections
    14821015\end{itemize}
    1483 
    1484 \subsubsection{Dark Image Creation}
    1485 
    1486 The Dark calibration stage shall construct a master dark image from a
    1487   collection of raw dark images.  The tasks and functions include:
    1488 
    1489 \begin{itemize}
    1490 
    1491 \item The Dark calibration stage raises an error if the input images
    1492   have exposure times which deviate by more than 2\%.
    1493 
    1494 \item The Dark calibration stage corrects the input dark images for
    1495   the bias.
    1496 
    1497 \item The Dark calibration stage combines the input images using the
    1498   statistic specified by the user, selected from one of the following:
    1499   sample mean, median, and mode, robust mean, median, and mode, and
    1500   the clipped mean and median.
    1501 
    1502 \item The Dark calibration stage constructs residual images, in which
    1503   the master dark is applied to the input images.
    1504 
    1505 \item Outlier residual images, those for which the residual level and
    1506   variance are excessive, are excluded from the input image stack and
    1507   the dark image reconstructed.
    1508 \end{itemize}
    1509 
    1510 \subsubsection{Flat-field Image Creation}
    1511 
    1512 The Flat-field calibration stage constructs a master flat-field image
    1513 from a collection of raw flat-field images.  The tasks and functions
    1514 include:
    1515 
    1516 \begin{itemize}
    1517 
    1518 \item The Flat-field calibration stage accepts a group of images from
    1519   one of the following flat-field sources: dome, twilight,
    1520   night-sky.
    1521 
    1522 \item The flat-field calibration stage raises an error if the
    1523   input images in a single stack used more than one of the above
    1524   flat-field sources or multiple filters.
    1525 
    1526 \item The Flat-field calibration stage corrects the input flat-field
    1527   images for the bias and dark.
    1528 
    1529 \item The Flat-field calibration stage combines the input images using
    1530   the statistic specified by the user, selected from one of the
    1531   following: sample mean, median, and mode, robust mean, median, and
    1532   mode, and the clipped mean and median.
    1533 
    1534 \item The Flat-field calibration stage constructs residual images, in
    1535   which the master flat-field is applied to the input images.
    1536 
    1537 \item Outlier residual images, those for which the residual level and
    1538   variance are excessive ($> 0.1$\%, or 1.02 times the Poisson limit
    1539   of the flat-field image), are excluded from the input image stack
    1540   and the flat-field image reconstructed.
    1541 \end{itemize}
    1542 
    1543 \subsubsection{Mask Image Creation}
    1544 
    1545 The Mask calibration stage constructs a bad-pixel mask from a stack of
    1546 raw flat-field images and a master flat-field image.  The tasks and
    1547 functions include:
    1548 
    1549 \begin{itemize}
    1550 
    1551 \item The Mask calibration stage masks the pixels which are
    1552   inconsistent in the input flats by more than 1\%, given sufficient
    1553   signal-to-noise in the input flats.
    1554 
    1555 \item The Mask calibration stage mask the pixels which are
    1556   consistently low or high in the input flats by more than a factor of
    1557   3 beyond the typical pixel.
    1558 
    1559 \item The Mask calibration stage masks the pixels identified in a
    1560   table of bad pixels generated externally to the calibration stage.
    1561 
    1562 \item The Mask calibration stage uses multiple bit values to identify
    1563   the different types of masked pixels.
    1564 
    1565 \item The Mask calibration stage raises an error if the input images
    1566   generate too many bad pixels in the mask.
    1567 \end{itemize}
    1568 
    1569 \subsubsection{Fringe-frame Creation}
    1570 
    1571 The Fringe-frame Creation calibration stage constructs a master fringe
    1572 frame from a stack of raw night-time sky images or from a stack of
    1573 dome fringe frames.  The tasks and functions include:
    1574 
    1575 \begin{itemize}
    1576 
    1577 \item The Fringe-frame Creation calibration stage raises an error if
    1578   the input stack consists is images generated with more than one type
    1579   of fringe source or with multiple filters.
    1580 
    1581 \item The Fringe-frame Creation calibration stage flattens the input
    1582   images to remove the pixel-to-pixel sensitivity variations of the
    1583   detector.
    1584 
    1585 \item The Fringe-frame Creation calibration stage measures the fringe
    1586   amplitude on the input fringe images.
    1587 
    1588 \item The Fringe-frame Creation calibration stage scales the input
    1589   fringe images based on the fringe amplitude.
    1590 
    1591 \item The Fringe-frame Creation calibration stage combines the scaled
    1592   input images using the statistic specified by the user, selected
    1593   from one of the following: sample mean, median, and mode, robust
    1594   mean, median, and mode, and the clipped mean and median.
    1595 
    1596 \item The Fringe-frame Creation calibration stage constructs residual
    1597   images, in which the master fringe image is applied to the input
    1598   images, along with all necessary preceding calibration images.
    1599 
    1600 \item The Fringe-frame Creation calibration stage measures the
    1601   residual fringe amplitude on the residual images.
    1602 \end{itemize}
    1603 
    1604 \subsubsection{Low-spatial-frequency Sky Models}
    1605 
    1606 The Sky Model calibration stage constructs a sky model image set from
    1607 a stack of raw night-time sky images.
    1608 
    1609 \subsubsection{Flat-field correction Frame Creation}
    1610 
    1611 The Flat-field correction calibration stage constructs a flat-field
    1612 correction image from dithered observations of a stellar field.  The
    1613 tasks and functions include:
    1614 
    1615 \begin{itemize}
    1616 
    1617 \item The Flat-field correction calibration stage constructs a
    1618   flat-field correction image from dithered observations of a stellar
    1619   field.
    1620 
    1621 \item The Flat-field correction calibration stage constructs a
    1622   flat-field correction image for each filter and camera
    1623   independently.
    1624 
    1625 \item The Flat-field correction calibration stage constructs a
    1626   correction image which makes the photometry of multiple observations
    1627   of the same stellar source consistent at different locations in the
    1628   focal plane.
    1629 
    1630 \item The Flat-field correction calibration stage constructs corrected
    1631   flat-field images using the measured correction.
    1632 
    1633 \item The Flat-field correction calibration stage determines the
    1634   consistency of the corrected flat-field images using the dithered
    1635   stellar field observations flattened with the corrected flat-field
    1636   image.
    1637 \end{itemize}
    1638 
    1639 \subsubsection{Non-linearity correction}
    1640 
    1641 The Non-linear correction calibration stage constructs a correction
    1642 model for low-level non-linearity effects in the detector.  The tasks
    1643 and functions include:
    1644 
    1645 \begin{itemize}
    1646 
    1647 \item The Non-linear correction calibration stage constructs a
    1648   non-linear correction from a collection of images of a constant
    1649   source with varying exposure times.
    1650 
    1651 \item The Non-linear correction calibration stage construct a
    1652   non-linear correction which linearizes the detector fluxes
    1653   $<0.5\%$.
    1654 
    1655 \item The Non-linear correction calibration stage determines the
    1656   saturation regime, in which the non-linear correction is no longer
    1657   consistent to $<0.5\%$.
    1658 \end{itemize}
    1659 
    1660 \subsubsection{Telescope Astrometry Parameters}
    1661 
    1662 \begin{itemize}
    1663 \item The IPP Calibration system constructs static models of the
    1664   telescope astrometry parameters (e.g., distortion, detector warps)
    1665   once per week.
    1666 
    1667 \item The IPP Calibration system constructs static models of the
    1668   telescope astrometry parameters (e.g., distortion, detector warps)
    1669   with an accuracy to produce astrometry consistent to 30
    1670   milliarcsec.
    1671 
    1672 \item The IPP Calibration system monitors changes in the telescope
    1673   astrometry parameters and issue a warning if the parameters change
    1674   by more than 2\%.
    1675 \end{itemize}
    1676 
    1677 \subsubsection{Zero-Point Monitoring}
    1678 
    1679 The IPP Calibration system determines telescope filter and camera
    1680 zero-points on a nightly basis with an accuracy sufficient to
    1681 determine photometry in the native filter systems to 5 millimags.
    16821016
    16831017\subsection{Modules}
     
    17941128
    17951129\item IPP Controller - Analysis Tasks.  The IPP Controller shall
    1796 initiate the Analysis Tasks and monitor their output and exit
     1130 initiate the Analysis Tasks and monitor their output and exit
    17971131status.\TASK
    17981132
     
    18351169
    18361170The report, `The Pan-STARRS Image Processing Pipeline Computational
    1837 Challange' (PSDC-4xx-xx) discusses the assumptions and measurements
     1171Challenge' (PSDC-400-006) discusses the assumptions and measurements
    18381172made to determine the IPP computing requirements, for both the PS-1
    18391173configuration and the PS-4 configuration, under multiple assumptions
Note: See TracChangeset for help on using the changeset viewer.