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/* CamLens.c 20 Feb 2008 TKS
implementaton of CamLens class
*/
/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "sphereAlign.h"
#include <stdlib.h>
#include <memory.h>
#include <math.h>
/* radius <=> angle functions for lens projections
R is noramlized image radius
K is an adjustable parameter
A is angle in radians
NOTE no error checks, pass only reasonable values!
|A| |R|
rect <Pi/2 any
fish any <= K
mirr any <= 2
ster <Pi any
*/
static double r2a_rect( double R, double K ){
return atan( R );
}
static double a2r_rect( double A, double K ){
return tan( A );
}
static double r2a_fish( double R, double K ){
return K * asin( R / K );
}
static double a2r_fish( double A, double K ){
return K * sin( A / K );
}
static double r2a_mirr( double R, double K ){
return asin( 0.5 * R );
}
static double a2r_mirr( double A, double K ){
return sin( 0.5 * A );
}
static double r2a_ster( double R, double K ){
return 2 * atan( R );
}
static double a2r_ster( double A, double K ){
return tan(0.5 * A);
}
// create empty
pCamLens CamLens_new0()
{
pCamLens p = (pCamLens) malloc(sizeof(CamLens));
if( p ) memset(p, 0, sizeof(CamLens));
return p;
}
/* initialize with minimal info
fmt is a PT format code
fails if fmt is not a "camera" projection
hfov is the angle corresponding to wid
flmm should be 0 for an ideal projection, >0 for a real lens
other assumptions see CamLens_setProjection()
*/
pCamLens CamLens_new1( int wid, int hgt, int fmt, double hfov, double flmm )
{
pCamLens p;
double R, x, y;
if( fmt < _rectilinear || fmt > _stereographic ) return 0;
p = CamLens_new0();
p->FLmm = flmm;
if( CamLens_setProjection( p, fmt )){
p->widpix = wid;
p->hgtpix = hgt;
p->FLmm = flmm;
// focal lengths in pixels
R = CamLens_RofA( p, DEG2RAD( 0.5 * hfov ) );
p->hFLpix = p->vFLpix = 0.5 * p->widpix / R;
// projection center
p->hCpix = 0.5 * wid;
p->vCpix = 0.5 * hgt;
// default crop radius circumscribes raster
x = y = 0;
p->Rcrop = CamLens_getR( p, x, y );
// reference radius inscribed in raster
if( p->hFLpix * p->vCpix > p->vFLpix * p->hCpix )
y = p->vCpix; // wid < hgt
else x = p->hCpix; // wid >= hgt
p->Rref = CamLens_getR( p, x, y );
}
if( p->widpix < 1 || p->hgtpix < 1
|| p->hFLpix == 0 ){
free(p);
p = 0;
}
return p;
}
/* set projection format
fmt is an image format code defined in panorama.h
returns 0 for unsupported format
1 for OK
Assumes --
ideal projection if FLmm == 0, else lens projection
equal-area fisheye lens for _equirectangular (the
ideal is equal-angle)
lens projects Y of cylindrical and equirectangular
and both axes of the elliptical formats
*/
int CamLens_setProjection( pCamLens p, int fmt )
{ // null format
p->PT_fmt = -1;
p->R2A = 0;
p->A2R = 0;
p->Klens = 0;
p->lensAxis = (p->FLmm ? 3 : 0 ); // elliptical
p->Rref = p->Rcrop = 0; // no limit
switch( fmt ){
case _rectilinear:
p->R2A = r2a_rect;
p->A2R = a2r_rect;
p->Klens = 1.0;
break;
case _panorama:
p->R2A = r2a_rect;
p->A2R = a2r_rect;
p->Klens = 1.0;
p->lensAxis &= 2; // lens Y only
break;
case _fisheye_circ:
case _fisheye_ff:
p->R2A = r2a_fish;
p->A2R = a2r_fish;
p->Klens = 2.0;
p->Rref = p->Rcrop = p->Klens;
break;
case _equirectangular:
if( p->FLmm ){
p->R2A = r2a_fish;
p->A2R = a2r_fish;
p->Klens = 2.0;
p->Rref = p->Rcrop = p->Klens;
p->lensAxis = 2; // Y only
}
break;
case _spherical_cp:
case _spherical_tp:
if( p->FLmm ){
p->R2A = r2a_fish;
p->A2R = a2r_fish;
p->Klens = 500.0;
p->Rref = p->Rcrop = p->Klens;
}
break;
case _mirror:
p->R2A = r2a_mirr;
p->A2R = a2r_mirr;
p->Klens = 1.0;
break;
case _orthographic:
p->R2A = r2a_fish;
p->A2R = a2r_fish;
p->Klens = 1.0;
p->Rref = p->Rcrop = p->Klens;
break;
case _stereographic:
p->R2A = r2a_ster;
p->A2R = a2r_ster;
p->Klens = 1.0;
break;
default:
p->lensAxis = 0;
return 0; // unsupported format
}
// OK
p->PT_fmt = fmt;
return 1; // OK
}
// initialize with full info
pCamLens CamLens_new( pCameraInfo pc, pLensInfo pl )
{
return 0; /// TBD ///
}
// normalized radius to angle in radians
double CamLens_AofR( pCamLens p, double R ){
if( p->R2A == 0 ) return R;
return (p->R2A)( R, p->Klens );
}
// angle in radians to normalized radius
double CamLens_RofA( pCamLens p, double A ){
if( p->A2R == 0 ) return A;
return (p->A2R)( A, p->Klens );
}
// get largest valid normalized radius
double CamLens_Rmax( pCamLens p ){
return p->Rcrop;
}
/* pixel coordinates to normalized radius */
double CamLens_getR( CamLens *p, double x, double y )
{
double dx = ( x - p->hCpix ) / p->hFLpix;
double dy = ( y - p->vCpix ) / p->vFLpix;
return sqrt( dx * dx + dy * dy );
}