Unverified Commit be2a14d6 authored by Oleg Alexandrov's avatar Oleg Alexandrov Committed by GitHub
Browse files

Fix for 0.5 pixel shift in the SAR model (#370) 

* Bugfix for a 0.5 pixel offset in the SAR model

* Fix tests too

* Beautify the test

* Remove extra code from the test
parent c214d460

src/UsgsAstroSarSensorModel.cpp

+3 −3
Original line number Diff line number Diff line
@@ -374,7 +374,7 @@ csm::ImageCoord UsgsAstroSarSensorModel::groundToImage( 
        groundPt, time, slantRangeValue, groundTolerance);



    double line = (time - m_startingEphemerisTime) / m_exposureDuration + 0.5;

    double sample = groundRange / m_scaledPixelWidth;

    double sample = groundRange / m_scaledPixelWidth + 0.5;

    return csm::ImageCoord(line, sample);

  } catch (std::exception& error) {

    std::string message = "Could not calculate groundToImage, with error [";
@@ -504,7 +504,7 @@ csm::EcefCoord UsgsAstroSarSensorModel::imageToGround( 
              imagePt.line, height, desiredPrecision);

  double time =

      m_startingEphemerisTime + (imagePt.line - 0.5) * m_exposureDuration;

  double groundRange = imagePt.samp * m_scaledPixelWidth;

  double groundRange = (imagePt.samp - 0.5) * m_scaledPixelWidth;

  std::vector<double> coeffs = getRangeCoefficients(time);

  double slantRange = groundRangeToSlantRange(groundRange, coeffs);
@@ -640,7 +640,7 @@ csm::EcefLocus UsgsAstroSarSensorModel::imageToProximateImagingLocus( 
  // Compute the slant range

  double time =

      m_startingEphemerisTime + (imagePt.line - 0.5) * m_exposureDuration;

  double groundRange = imagePt.samp * m_scaledPixelWidth;

  double groundRange = (imagePt.samp - 0.5) * m_scaledPixelWidth;

  std::vector<double> coeffs = getRangeCoefficients(time);

  double slantRange = groundRangeToSlantRange(groundRange, coeffs);

tests/SarTests.cpp

+4 −5
Original line number Diff line number Diff line
@@ -43,14 +43,13 @@ TEST_F(SarSensorModel, State) { 
TEST_F(SarSensorModel, Center) {

  csm::ImageCoord imagePt(500.0, 500.0);

  csm::EcefCoord groundPt = sensorModel->imageToGround(imagePt, 0.0);

  EXPECT_NEAR(groundPt.x, 1737387.8590770673, 1e-3);

  EXPECT_NEAR(groundPt.y, -5303.280537826621, 1e-3);

  EXPECT_NEAR(groundPt.x, 1737387.8671710272, 1e-3);

  EXPECT_NEAR(groundPt.y, -5300.6282306119301, 1e-3);

  EXPECT_NEAR(groundPt.z, -3749.9796183814506, 1e-3);

}



TEST_F(SarSensorModel, GroundToImage) {

  csm::EcefCoord groundPt(1737387.8590770673, -5303.280537826621,

                          -3749.9796183814506);

  csm::EcefCoord groundPt(1737387.8671710272, -5300.6282306119301, -3749.9796358514604);

  csm::ImageCoord imagePt = sensorModel->groundToImage(groundPt, 0.001);

  EXPECT_NEAR(imagePt.line, 500.0, 1e-3);

  EXPECT_NEAR(imagePt.samp, 500.0, 1e-3);
@@ -100,7 +99,7 @@ TEST_F(SarSensorModel, imageToProximateImagingLocus) { 
      0.001,

      &precision,

      &warnings);

  EXPECT_NEAR(locus.point.x, 1737388.1260092105, 1e-2);

  EXPECT_NEAR(locus.point.x, 1737388.1411342232, 1e-2);

  EXPECT_NEAR(locus.point.y, -5403.0102509726485, 1e-2);

  EXPECT_NEAR(locus.point.z, -3749.9801945280433, 1e-2);

  EXPECT_NEAR(locus.direction.x, 0.002701478402694769, 1e-5);