imageTransforms_test.cpp

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/** \file imageTransforms_test.cpp
 */
#include "../../catch2/catch.hpp"
 
#include <vector>
#include <Eigen/Dense>
 
#define MX_NO_ERROR_REPORTS
 
#include "../../../include/math/func/gaussian.hpp"
 
#include "../../../include/improc/imageUtils.hpp"
#include "../../../include/improc/eigenCube.hpp"
 
#include "../../../include/improc/imageTransforms.hpp"
 
namespace
{
double imageMSE( const mx::improc::eigenImage<double> &a, const mx::improc::eigenImage<double> &b )
{
    return ( a - b ).square().mean();
}
} // namespace
 
/** Scenario: Verify direction and accuracy of various image shifts
 *
 * Tests image shifts by fractional pixels.
 *
 * \anchor tests_improc_imageTransforms_imageShift
 */
SCENARIO( "Verify direction and accuracy of various image shifts", "[improc::imageTransforms]" )
{
    GIVEN( "a Gaussian image" )
    {
        WHEN( "shifting" )
        {
            mx::improc::eigenImage<double> im, shift, ref;
 
            im.resize( 256, 256 );
            shift.resize( im.rows(), im.cols() );
            ref.resize( im.rows(), im.cols() );
 
            // Use sigma = 8 to get a well oversampled image, making shifts more accurate
            mx::math::func::gaussian2D<double>( im.data(), im.rows(), im.cols(), 0., 1.0, 127.5, 127.5, 8 );
 
            mx::improc::imageShift( shift, im, -0.5, -0.5, mx::improc::cubicConvolTransform<double>() );
            mx::math::func::gaussian2D<double>( ref.data(), ref.rows(), ref.cols(), 0., 1.0, 127.0, 127.0, 8 );
            REQUIRE_THAT( imageMSE( shift, ref ), Catch::Matchers::WithinAbs( 0.0, 1e-5 ) );
 
            mx::improc::imageShift( shift, im, +0.5, +0.5, mx::improc::cubicConvolTransform<double>() );
            mx::math::func::gaussian2D<double>( ref.data(), ref.rows(), ref.cols(), 0., 1.0, 128.0, 128.0, 8 );
            REQUIRE_THAT( imageMSE( shift, ref ), Catch::Matchers::WithinAbs( 0.0, 1e-5 ) );
 
            mx::improc::imageShift( shift, im, +1.0, +1.0, mx::improc::cubicConvolTransform<double>() );
            mx::math::func::gaussian2D<double>( ref.data(), ref.rows(), ref.cols(), 0., 1.0, 128.5, 128.5, 8 );
            REQUIRE_THAT( imageMSE( shift, ref ), Catch::Matchers::WithinAbs( 0.0, 1e-5 ) );
 
            mx::improc::imageShift( shift, im, +0.5, -0.5, mx::improc::cubicConvolTransform<double>() );
            mx::math::func::gaussian2D<double>( ref.data(), ref.rows(), ref.cols(), 0., 1.0, 128.0, 127.0, 8 );
            REQUIRE_THAT( imageMSE( shift, ref ), Catch::Matchers::WithinAbs( 0.0, 1e-5 ) );
 
            mx::improc::imageShift( shift, im, -0.3, +0.7, mx::improc::cubicConvolTransform<double>() );
            mx::math::func::gaussian2D<double>( ref.data(), ref.rows(), ref.cols(), 0., 1.0, 127.2, 128.2, 8 );
            REQUIRE_THAT( imageMSE( shift, ref ), Catch::Matchers::WithinAbs( 0.0, 1e-5 ) );
 
            mx::improc::imageShift( shift, im, 1.3, -0.7, mx::improc::cubicConvolTransform<double>() );
            mx::math::func::gaussian2D<double>( ref.data(), ref.rows(), ref.cols(), 0., 1.0, 128.8, 126.8, 8 );
            REQUIRE_THAT( imageMSE( shift, ref ), Catch::Matchers::WithinAbs( 0.0, 1e-5 ) );
        }
    }
}