/usr/include/astrometry/tweak2.h is in libastrometry-dev 0.73+dfsg-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | /*
# This file is part of the Astrometry.net suite.
# Licensed under a 3-clause BSD style license - see LICENSE
*/
#ifndef TWEAK_2_H
#define TWEAK_2_H
#include "astrometry/sip.h"
/**
Given an initial WCS solution, compute SIP polynomial distortions
using an annealing-like strategy. That is, it finds matches between
image and reference catalog by searching within a radius, and that
radius is small near a region of confidence, and grows as you move
away. That makes it possible to pick up more distant matches, but
they are downweighted in the fit. The annealing process reduces the
slope of the growth of the matching radius with respect to the
distance from the region of confidence.
In Astrometry.net, the confidence region is the center of the quad
that matched.
fieldxy: source positions, x0,y0,x1,y1,...
Nfield: number of source positions
fieldjitter: standard deviation of field sources, in pixels;
(FIXME: this should be per-source!)
W, H: size of the image.
indexradec: reference star positions, in degrees, ra0,dec0,ra1,dec1,...
Nindex: number of reference stars
indexjitter: standard deviation of reference sources, in arcsec.
(FIXME: this should be per-source)
quadcenter: the center of the quad that matched, in pixels.
quadR2: the radius-squared, in pixels, of the quad that matched.
distractors: how often you find unexpected test stars; we've always kept this fixed at 0.25
logodds_bail: totally uninteresting; shouldn't really be here. Set to, say, -100.
sip_order: polynomial distortion order you want. 1=linear works.
startwcs: initial WCS solution. See util/sip.h : sip_wrap_tan() if you have a tan_t rather than a sip_t.
destwcs: where to put the solution; NULL to allocate a new sip_t.
newtheta: "theta" maps field stars to reference stars in the final matching that we produce. Set this non-NULL to pull it out.
newodds: this tells the confidence in the matches. Use verify_logodds_to_weight() to turn these into a weight in [0,1].
crpix: if you want to keep the reference point fixed, set this to a (2-element) array of the image reference position.
*/
sip_t* tweak2(const double* fieldxy, int Nfield,
double fieldjitter,
int W, int H,
const double* indexradec, int Nindex,
double indexjitter,
const double* quadcenter, double quadR2,
double distractors,
double logodds_bail,
int sip_order,
int sip_invorder,
const sip_t* startwcs,
sip_t* destwcs,
int** newtheta, double** newodds,
double* crpix,
double* p_logodds,
int* p_besti,
int* testperm, int startorder);
#endif
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