LineScanCameraSkyMap.cpp

 
/* SPDX-License-Identifier: CC0-1.0 */
 
#include "LineScanCameraSkyMap.h"
#include "CameraFocalPlaneMap.h"
#include "CameraDistortionMap.h"
#include "iTime.h"
#include "LineScanCameraDetectorMap.h"
 
namespace Isis {
  bool LineScanCameraSkyMap::SetSky(const double ra, const double dec) {
    // Get beginning bounding time and offset for iterative loop
    p_camera->Sensor::setTime(p_camera->Spice::cacheStartTime());
    p_camera->Sensor::SetRightAscensionDeclination(ra, dec);
 
    double lookC[3];
    p_camera->Sensor::LookDirection(lookC);
    double ux = p_camera->FocalLength() * lookC[0] / lookC[2];
    double uy = p_camera->FocalLength() * lookC[1] / lookC[2];
 
    CameraDistortionMap *distortionMap = p_camera->DistortionMap();
    if(!distortionMap->SetUndistortedFocalPlane(ux, uy)) return false;
    double dx = distortionMap->FocalPlaneX();
    double dy = distortionMap->FocalPlaneY();
 
    CameraFocalPlaneMap *focalMap = p_camera->FocalPlaneMap();
    if(!focalMap->SetFocalPlane(dx, dy)) return false;
    double startOffset = focalMap->DetectorLineOffset() -
                         focalMap->DetectorLine();
 
    // Get ending bounding time and offset for iterative loop
    p_camera->Sensor::setTime(p_camera->Spice::cacheEndTime());
    p_camera->Sensor::SetRightAscensionDeclination(ra, dec);
 
    p_camera->Sensor::LookDirection(lookC);
    ux = p_camera->FocalLength() * lookC[0] / lookC[2];
    uy = p_camera->FocalLength() * lookC[1] / lookC[2];
 
    if(!distortionMap->SetUndistortedFocalPlane(ux, uy)) return false;
    dx = distortionMap->FocalPlaneX();
    dy = distortionMap->FocalPlaneY();
 
    if(!focalMap->SetFocalPlane(dx, dy)) return false;
    double endOffset = focalMap->DetectorLineOffset() -
                       focalMap->DetectorLine();
 
    // Make sure we are in the image
    if((startOffset < 0.0) && (endOffset < 0.0)) return false;
    if((startOffset > 0.0) && (endOffset > 0.0)) return false;
 
    // Get everything ordered for iteration
    double fl, fh, xl, xh;
    if(startOffset < endOffset) {
      fl = startOffset;
      fh = endOffset;
      xl = p_camera->Spice::cacheStartTime().Et();
      xh = p_camera->Spice::cacheEndTime().Et();
    }
    else {
      fl = endOffset;
      fh = startOffset;
      xl = p_camera->Spice::cacheEndTime().Et();
      xh = p_camera->Spice::cacheStartTime().Et();
    }
 
    // Iterate to find the time at which the instrument imaged the ground point
    LineScanCameraDetectorMap *detectorMap =
      (LineScanCameraDetectorMap *) p_camera->DetectorMap();
    double timeTol = detectorMap->LineRate() / 10.0;
    for(int j = 0; j < 30; j++) {
      double etGuess = xl + (xh - xl) * fl / (fl - fh);
      p_camera->Sensor::setTime(etGuess);
      p_camera->Sensor::SetRightAscensionDeclination(ra, dec);
      p_camera->Sensor::LookDirection(lookC);
      ux = p_camera->FocalLength() * lookC[0] / lookC[2];
      uy = p_camera->FocalLength() * lookC[1] / lookC[2];
 
      if(!distortionMap->SetUndistortedFocalPlane(ux, uy)) return false;
      dx = distortionMap->FocalPlaneX();
      dy = distortionMap->FocalPlaneY();
 
      if(!focalMap->SetFocalPlane(dx, dy)) return false;
      double f = focalMap->DetectorLineOffset() -
                 focalMap->DetectorLine();
 
      double delTime;
      if(f < 0.0) {
        delTime = xl - etGuess;
        xl = etGuess;
        fl = f;
      }
      else {
        delTime = xh - etGuess;
        xh = etGuess;
        fh = f;
      }
 
      // See if we converged on the point so set up the undistorted
      // focal plane values and return
      if(fabs(delTime) < timeTol || f == 0.0) {
        p_focalPlaneX = ux;
        p_focalPlaneY = uy;
        return true;
      }
    }
    return false;
  }
}