VIMOS DRS Reference Manual 2.9.3
|
Functions | |
VimosBool | VmAstroComputeCD (VimosTableArray *calTables, const VimosImage *refImage) |
Fit a CD matrix (pointing and rotation) | |
VimosBool | VmAstroComputeCO (VimosImage *calImage, float tolrad, float sigClip, VimosTable *stmcTable, unsigned int tflag, double tdevmax) |
Fit a CO matrix (scale and distortions) | |
VimosTable * | resetAstroTable (int count, char *filterName) |
Build Astrometric Table. | |
VimosTable * | resetStarMatchTable (int count, int naxis1, int naxis2) |
Build StarMatchTable Table. | |
VimosTable * | shiftStarMatch (VimosTable **starMatchTable) |
Build StarMatchTable Table. | |
int | calcres (VimosTable *o_star, VimosTable *a_star, int imatch[], int nmatch, double *rms) |
Compute the RMS error of the CCD <-> Sky transformation. |
The module provides the utility functions to determine the correct astrometry (CD and CO matrices) for a VIMOS image.
int calcres | ( | VimosTable * | o_star, |
VimosTable * | a_star, | ||
int | imatch[], | ||
int | nmatch, | ||
double * | rms | ||
) |
Compute the RMS error of the CCD <-> Sky transformation.
wcs | wcs structure |
o_star | star table |
a_star | astrometric table |
imatch | table of matching indexes |
nmatch | number of matches |
rms | pointer to the returned array |
Compute the RMS error of the CCD <-> Sky transformation.
VimosTable* resetAstroTable | ( | int | count, |
char * | filterName | ||
) |
Build Astrometric Table.
count | N. of entries |
filterName | Image filter |
Build up an astrometric Table (empty) of count*count rows for filter FilterName (used by VmImComputeCO)
VimosTable* resetStarMatchTable | ( | int | count, |
int | naxis1, | ||
int | naxis2 | ||
) |
Build StarMatchTable Table.
count | N. of entries |
Build up an StarTable Table of count*count rows Fill it up with an equally spaced grid of count*count points (used by VmImComputeCO)
VimosTable* shiftStarMatch | ( | VimosTable ** | starMatchTable | ) |
Build StarMatchTable Table.
**starMatchTable | Array of 4 StarMatchTables (1 per quadrant) |
put together the 4 tables, different for each quadrant we must change the image coordinates, and then change the CRPIX1 and 2 values to 0,0
for positive X quads (quad 1 and 4) it is: new X = oldX-crpix1-0.5 for neg. X quads (2 and 3) new X = -crpix1+oldX+0.5 for pos. Y quads (1 and 2) new Y = oldY-crpix2-0.5 for neg. Y quads (3 and 4) new Y = -crpix2+oldY+0.5
VimosBool VmAstroComputeCD | ( | VimosTableArray * | calTables, |
const VimosImage * | refImage | ||
) |
Fit a CD matrix (pointing and rotation)
VM_TRUE
or VM_FALSE
calTables | Set of star match tables from different quadrants. |
refImage | Reference image. |
The function merges the star match tables from the input set set into a single star match table having the origin of the coordinate system a pixel (0, 0) (given by the CRPIXi keywords). The new CD matrix is computed fitting pixels versus right ascension and declination.
The reference image refImage is used to obtain the image size in pixels of the images from which the input star match tables were created. It is assumed that all images have the same size.
The headers of each star match table in the input set is updated with the computed CD matrix.
VimosBool VmAstroComputeCO | ( | VimosImage * | calImage, |
float | tolrad, | ||
float | sigClip, | ||
VimosTable * | stmcTable, | ||
unsigned int | tflag, | ||
double | tdevmax | ||
) |
Fit a CO matrix (scale and distortions)
calImage | The image for which CO has to be computed |
tolrad | Search radius. |
sigClip | Threshold for sigma clipping (?) |
stmcTable | Star match table. |
tflag | Flag to enable/disable temperature checks |
tdevmax | Tolerance in C for beam temperature |
VM_TRUE
or VM_FALSE
The function reads the CD matrix from the image calImage, or, if the a star match table was given, i.e. stmcTable is different from NULL
, it is taken from stmcTable.
An artificial star table with a grid of 10 times 10 points is created and the CCD to sky coordinate transformation is applied to them, computing right ascension and declination. The right ascension and declination are used to build an astrometric table, and from both tables, star table and astrometric table, a star match table is created and the CO matrix is fitted. The result is an image calImage having a CO matrix which comprises wcs and CcdToSky.
For details on the temperature check see the documentation for computeVirtualPixels