Changeset 5377 for trunk/doc/modules/CameraImages.tex

Timestamp:

Oct 18, 2005, 5:24:11 PM (21 years ago)

Author:

eugene

Message:

cleaned up astrom / fringe additions

File:

• trunk/doc/modules/CameraImages.tex (modified) (10 diffs)

trunk/doc/modules/CameraImages.tex

@@ -724 +724 @@
 output; otherwise it shall return \code{false}.
 
-\subsection{Astrometry Fitting Support Routines}
+\subsection{Astrometry Analysis}
 
 Astrometry is performed on an astronomical image after a collection of
@@ -734 +734 @@
 of the other coordinate system.  For example, it might be necessary to
 determine the coordinates of the \code{psReadout} pixels relative to
-the \code{psCell} (rather accept the relationship defined by the
-metadata).  
+the \code{psCell} (rather than accept the relationship defined by the
+metadata).
 
 For the moment, we define two layers of astrometric analysis which
@@ -747 +747 @@
 the second case, a collection of detectors on a collection of chips
 from a mosaic camera are used to measure the position of the telescope
-boresite, the camera rotation, the impact of distortion from the
+boresight, the camera rotation, the impact of distortion from the
 telescope optics, and the chip-to-focal plane transformation resulting
-from chip placement errors or possible detector tilts or warps.  
+from chip placement errors or possible detector tilts or warps.
 
 The process of performing astrometry involves the following steps:
@@ -769 +769 @@
 possible the above analysis steps.  
 
+\subsubsection{Astrometry Objects}
+
 We define the following structure to carry the necessary information
 about each detection.  
 \begin{datatype}
 typedef struct {
-    double X, Y;
-    double L, M;
-    double P, Q;
-    double R, D;
-    double Mag;
+    psPlane pix;
+    psPlane FP;
+    psPlane TP;
+    psSphere sky;
+    double mag;
 } pmAstromObj;
 \end{datatype}
 This structure specifies the coordinate of the detection in each of
-the four necessary coordinate frames: \code{X,Y} define the position
-in the \code{psReadout} frame, \code{L,M} define the position in the
-\code{psChip} frame, \code{P,Q} define the position in the
-\code{psFPA} frame, \code{R,D} define the position on the Celestial
-Sphere.  \tbd{re-write using psPlane and psSphere?}.  In addition, a
-measurement of the brightness is given by the element \code{Mag}.
-Such a data structure should be used for both the raw and the
-reference stars.  In astrometric processing, the raw detections will
-be projected using the best available information to each of these
-coordinate frames from the \code{X,Y} coordinates, while the reference
-detections will be projected to the other frames from the \code{R,D}
-coordinates.
+the four necessary coordinate frames: \code{pix} defines the position
+in the \code{psReadout} frame, \code{FP} defines the position in the
+Focal Plane frame, \code{TP} defines the position in the Tangent Plane
+frame, \code{sky} defines the position on the Celestial Sphere.  In
+addition, a measurement of the brightness is given by the element
+\code{Mag}.  Such a data structure should be used for both the raw and
+the reference stars.  In astrometric processing, the raw detections
+will be projected using the best available information to each of
+these coordinate frames from the \code{pix} coordinates, while the
+reference detections will be projected to the other frames from the
+\code{sky} coordinates.
 
 The raw detections and the reference stars are both projected to a
-common coordinate frame for analysis.  In these modules, we
-principally use the Focal Plane for this reference frame.  After
-projection to the common frame, it is necessary to determine the match
-between corresponding objects in the two lists.  In order to match the
-raw detections to the reference stars, different methods are used
-depending on the circumstance.  
+common coordinate frame for analysis.  In these modules, we use the
+Focal Plane for this reference frame.  After projection to the common
+frame, it is necessary to determine the match between corresponding
+objects in the two lists.  In order to match the raw detections to the
+reference stars, different methods are used depending on the
+circumstance.
+
+\subsubsection{Matching Stars : Close Match}
 
 If the two sets of coordinates are expected to agree very well (ie,
 the current best-guess astrometric solution is quite close to the
-'true' astrometric solution), then it is possible to use the simplest
+`true' astrometric solution), then it is possible to use the simplest
 matching process: cross-correlation within a fixed radius.  The
 following function accepts two sets of \code{pmAstromObj} sources and
 determines the matched objects between the two lists.  The input
 sources must have been projected to the Focal Plane coordinates
-(\code{pmAstromObj.L,M}), and the supplied \code{config} entry must
+(\code{pmAstromObj.FP}), and the supplied \code{options} entry must
 contain the desired match radius (keyword:
-\code{ASTROM_MATCH_RADIUS}).  The output consists an array of
+\code{ASTROM.MATCH.RADIUS}).  The output consists an array of
 \code{pmAstromMatch} values, defined below.
 
 \begin{prototype}
-psArray *pmAstromRadiusMatch (psArray *st1, psArray *st2, pmAstromOpt *opt);
+psArray *pmAstromRadiusMatch (psArray *starlist1, psArray *starlist2, psMetadata *options);
 \end{prototype}
 
 \begin{datatype}
 typedef struct {
-    int i1;
-    int i2;
+    int idx1;
+    int idx2;
 } pmAstromMatch;
 \end{datatype}
 The \code{pmAstromMatch} structure defines the cross-correlation
 between two arrays.  An single such data item specifies that item
-number \code{pmAstromMatch.i1} in the first list corresponds to
-\code{pmAstromMatch.i2} in the second list.  
+number \code{pmAstromMatch.idx1} in the first list corresponds to
+\code{pmAstromMatch.idx2} in the second list.  
+
+\subsubsection{Matching Stars : Rough Match}
 
 If the two sets of coordinates are not known to agree well, a somewhat
@@ -857 +862 @@
 rotations.  We define the following function to apply this matching algorithm: 
 \begin{prototype}
-pmAstromGridMatchStat pmAstromGridMatch (psArray *st1, psArray *st2, psMetadata *options);
+psArray *pmAstromGridMatch (psArray *starlist1, psArray *starlist2, psMetadata *options);
 \end{prototype}
 The input sources must have been projected to the Focal Plane
-coordinates (\code{pmAstromObj.L,M}), and the supplied \code{config}
+coordinates (\code{pmAstromObj.FP}), and the supplied \code{options}
 entry must contain the following user-defined parameters:
 \begin{itemize}
-\item \code{GRID_OFFSET} : maximum allowed displacement in search
-\item \code{GRID_SCALE}  : grid bin size in focal-plane coordinate units
-\item \code{MIN_ANGLE} : minimum tested relative rotation 
-\item \code{MAX_ANGLE} : maximum tested relative rotation 
-\item \code{DEL_ANGLE} : relative rotation step size
+\item \code{GRID.OFFSET}    : maximum allowed displacement in search
+\item \code{GRID.SCALE}     : grid bin size in focal-plane coordinate units
+\item \code{GRID.MIN.ANGLE} : minimum tested relative rotation 
+\item \code{GRID.MAX.ANGLE} : maximum tested relative rotation 
+\item \code{GRID.DEL.ANGLE} : relative rotation step size
 \end{itemize}
-The output from this process is the statistics of the best-fit
-(rotation and offset grid cell).  This information is returned in the
-\code{pmAstromGridMatchStats} structure:
-\begin{datatype}
-typedef struct {
-    double angle;
-    double dL;
-    double dM;
-    double minMetric;
-    double minVar;
-    int    nMatch;
-} pmAstromGridMatchStats;
-\end{datatype}
-The elements \code{angle}, \code{dL}, \code{dM} define the best
-rotation and offset; the element \code{nMatch} indicates the number of
-matched sources which fell within the match bin; the element
-\code{minVar} defines the variance of the sources within the match
-bin; the element \code{minMetric} specifies the value of the selection
-metric for the matched bin.  Note that the metric of choice may not
-necessarily be either the simple number of sources or the varience.
-We find that a combination based on both which enhances the importance
-of having a well-populated bin with a minimal variance gives good
-results: $\mbox{metric} = \mbox{var} \times N^{-4}$.  
-
-We define two additional functions which are used in two build
-\code{pmAstromGridMatch}, but which may be useful on their own:
-
-\begin{prototype}
-pmAstromGridMatchStats pmAstromGridMatchAngle (psArray *st1, psArray *st2, psMetadata *config);
-\end{prototype}
-This function is identical to \code{pmAstromGridMatch}, but is valid
-for only a single relative rotation.  The input \code{config}
-information need not contain any of the \code{ANGLE} entries. 
-
-\begin{prototype}
-psArray *pmAstromRotateObj (psArray *old, double angle, double pCenter, double qCenter);
-\end{prototype}
-This function accepts an array of \code{pmAstromObj} objects and
-rotates them by the given \code{angle} about the given center
-coordinate \code{pCenter,qCenter} in the Focal Plane Array
-coordinates.  
+Note that the angles are defined as counter-clockwise rotations of
+starlist 1 relative to starlist 2.
+
+This function returns all matched pairs identified in the grid cell.
+It also adds to the \code{options} metadata several elements defining
+the statistics of the best-fit (rotation and offset grid cell):
+\begin{itemize}
+\item \code{GRID.FIT.ANGLE}
+\item \code{GRID.FIT.LOFF}
+\item \code{GRID.FIT.MOFF}
+\item \code{GRID.FIT.METRIC}
+\item \code{GRID.FIT.VARIANCE}
+\item \code{GRID.FIT.NMATCH}
+\end{itemize}
+The elements \code{GRID.FIT.ANGLE}, \code{GRID.FIT.LOFF},
+\code{GRID.FIT.MOFF} define the best rotation and offset; the element
+\code{GRID.FIT.NMATCH} indicates the number of matched sources which
+fell within the match bin; the element \code{GRID.FIT.VAR} defines the
+variance of the sources within the match bin; the element
+\code{GRID.FIT.METRIC} specifies the value of the selection metric for
+the matched bin.  Note that the metric of choice may not necessarily
+be either the simple number of sources or the varience.  We find that
+a combination based on both which enhances the importance of having a
+well-populated bin with a minimal variance gives good results:
+$\mbox{metric} = \mbox{var} \times N^{-4}$.  
 
 The result of a \code{pmAstromGridMatch} may be used to modify the
@@ -920 +909 @@
 two adjustments are made using the function:
 \begin{prototype}
-pmAstromApplyGridMatch (pmFPA *fpa, pmAstromGridMatchStats stats);
+bool pmAstromApplyGridMatch (pmFPA *fpa, pmAstromGridMatchStats stats);
 \end{prototype}
 This function modifies the supplied \code{pmFPA} entry as described
 above.
+
+We define two additional functions which are used in two build
+\code{pmAstromGridMatch}, but which may be useful on their own:
+
+\begin{prototype}
+psArray *pmAstromGridMatchAngle (psArray *starlist1, psArray *starlist2, psMetadata *options);
+\end{prototype}
+This function is identical to \code{pmAstromGridMatch}, but is valid
+for only a single relative rotation.  The input \code{config}
+information need not contain any of the \code{GRID.*.ANGLE} entries
+(they will be ignored).
+
+\begin{prototype}
+psArray *pmAstromRotateObj (psArray *old, double angle, double pCenter, double qCenter);
+\end{prototype}
+This function accepts an array of \code{pmAstromObj} objects and
+rotates them by the given \code{angle} about the given center
+coordinate \code{pCenter,qCenter} in the Focal Plane Array
+coordinates.  
+
+\subsubsection{Astrometry Fitting Routines}
 
 The result of a \code{pmAstromRadiusMatch} operation is a list of
@@ -937 +947 @@
 fitting uses clipping to exclude outliers, likely representing poor
 matches.  The \code{config} element must contain the information
-\code{ASTROM_NSIGMA} (specifying the number of sigma used in the
-clipping) and \code{ASTROM_NCLIP} (specifying the number of clipping
+\code{ASTROM.NSIGMA} (specifying the number of sigma used in the
+clipping) and \code{ASTROM.NCLIP} (specifying the number of clipping
 iterations must be performed).  The \code{config} element must also
 specify the order of the polynomial fit (keyword:
-\code{ASTROM_ORDER}).  The result of this fit is a set of
+\code{ASTROM.ORDER}).  The result of this fit is a set of
 modifications of the components of the \code{pmFPA.toTangentPlane}
 transformation, and the modifications of the reference coordinate of
@@ -961 +971 @@
 systems.  The fitting uses clipping to exclude outliers, likely
 representing poor matches.  The \code{config} element must contain the
-information \code{ASTROM_NSIGMA} (specifying the number of sigma used
-in the clipping) and \code{ASTROM_NCLIP} (specifying the number of
+information \code{ASTROM.NSIGMA} (specifying the number of sigma used
+in the clipping) and \code{ASTROM.NCLIP} (specifying the number of
 clipping iterations must be performed).  The \code{config} element
 must also specify the order of the polynomial fit (keyword:
-\code{ASTROM_ORDER}).  The result of this fit is a set of
+\code{ASTROM.ORDER}).  The result of this fit is a set of
 modifications of the components of the \code{pmChip.toFPA}
 transformation.
@@ -980 +990 @@
 plane, for a collection of raw measurements and matched reference
 stars.  The configuration data must include the bin size over which
-the gradient is measured (keyword: \code{ASTROM_GRAD_BOX}).  The
+the gradient is measured (keyword: \code{ASTROM.GRAD.BOX}).  The
 function returns an array of \code{pmAstromGradient} structures,
 defined below.
 \begin{prototype}
-psArray pmAstromMeasureGradients (psArray *st1, psArray *st2, psArray *match, psMetadata *config);
+psArray pmAstromMeasureGradients (psArray *starlist1, psArray *starlist2, psArray *match, psMetadata *config);
 \end{prototype}
 
 The following data structure carries the information about the
 residual gradient of source positions in the tangent plane
-(\code{P,Q}) as a function of position in the focal plane
-(\code{L,M}).
+(\code{pmAstromObj.TP}) as a function of position in the focal plane
+(\code{pmAstromObj.FP}).
 \begin{datatype}
 typedef struct {
-    double L;
-    double M;
-    double dPdL;
-    double dPdM;
-    double dQdL;
-    double dQdM;
+    psPlane FP;
+    psPlane dTPdL;
+    psPlane dTPdM;
 } pmAstromGradient;
 \end{datatype}
@@ -1008 +1015 @@
 transformation of the supplied \code{pmFPA} structure.  The
 configuration variable supplies the polynomial order (keyword:
-\code{ASTROM_DISTORT_ORDER}).
+\code{ASTROM.DISTORT.ORDER}).
 \begin{prototype}
 psArray pmAstromFitDistortion (pmFPA *fpa, psArray *gradients, psMetadata *config);
 \end{prototype}
-
-\tbd{can we use the pmAstromFitMatch func above to fit the remaining
-  power in the chips?}
-