ComplexFftInverse

Computes the Fast Fourier inverse Transform of an image.

Access to parameter description

For an introduction: see section Frequency Domain.

This algorithm computes the inverse FFT of an image. The result is two floating point images, respectively the real and imaginary parts of the complex inverse Fourier Transform.

Remarks

A classical operation is to first filter the spectrum of an image (especially to suppress high frequencies usually associated with noise), and then reconstruct the input image using ComplexFftInverse with the filtered spectrum and unchanged phase as input images.
Images are centered in the upper left corner. The ComplexCenteredFft algorithm can be used to directly get a centered FFT.

See also

Function Syntax

This function returns a ComplexFftInverseOutput structure containing outputRealImage and outputImaginaryImage.

// Output structure of the complexFftInverse function.
struct ComplexFftInverseOutput
{
    /// The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
    std::shared_ptr< iolink::ImageView > outputRealImage;
    /// The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
    std::shared_ptr< iolink::ImageView > outputImaginaryImage;
};

// Function prototype
ComplexFftInverseOutput
complexFftInverse( std::shared_ptr< iolink::ImageView > inputRealImage,
                   std::shared_ptr< iolink::ImageView > inputImaginaryImage,
                   std::shared_ptr< iolink::ImageView > outputRealImage = nullptr,
                   std::shared_ptr< iolink::ImageView > outputImaginaryImage = nullptr );

This function returns a tuple containing output_real_image and output_imaginary_image.

// Function prototype.
complex_fft_inverse(input_real_image: idt.ImageType,
                    input_imaginary_image: idt.ImageType,
                    output_real_image: idt.ImageType = None,
                    output_imaginary_image: idt.ImageType = None) -> Tuple[idt.ImageType, idt.ImageType]

This function returns a ComplexFftInverseOutput structure containing outputRealImage and outputImaginaryImage.

/// Output structure of the ComplexFftInverse function.
public struct ComplexFftInverseOutput
{
    /// 
    /// The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
    /// 
    public IOLink.ImageView outputRealImage;
    /// 
    /// The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
    /// 
    public IOLink.ImageView outputImaginaryImage;
};

// Function prototype.
public static ComplexFftInverseOutput
ComplexFftInverse( IOLink.ImageView inputRealImage,
                   IOLink.ImageView inputImaginaryImage,
                   IOLink.ImageView outputRealImage = null,
                   IOLink.ImageView outputImaginaryImage = null );

Class Syntax

// Command constructor.
ComplexFftInverse();

/// Gets the inputRealImage parameter.
/// The real part input image. It must be a floating point image.
std::shared_ptr< iolink::ImageView > inputRealImage() const;
/// Sets the inputRealImage parameter.
/// The real part input image. It must be a floating point image.
void setInputRealImage( std::shared_ptr< iolink::ImageView > inputRealImage );

/// Gets the inputImaginaryImage parameter.
/// The imaginary part input image. This image must have same dimensions and data type as the real input image.
std::shared_ptr< iolink::ImageView > inputImaginaryImage() const;
/// Sets the inputImaginaryImage parameter.
/// The imaginary part input image. This image must have same dimensions and data type as the real input image.
void setInputImaginaryImage( std::shared_ptr< iolink::ImageView > inputImaginaryImage );

/// Gets the outputRealImage parameter.
/// The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
std::shared_ptr< iolink::ImageView > outputRealImage() const;
/// Sets the outputRealImage parameter.
/// The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
void setOutputRealImage( std::shared_ptr< iolink::ImageView > outputRealImage );

/// Gets the outputImaginaryImage parameter.
/// The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
std::shared_ptr< iolink::ImageView > outputImaginaryImage() const;
/// Sets the outputImaginaryImage parameter.
/// The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.
void setOutputImaginaryImage( std::shared_ptr< iolink::ImageView > outputImaginaryImage );


// Method to launch the command.
void execute();

# Property of the inputRealImage parameter.
ComplexFftInverse.input_real_image
# Property of the inputImaginaryImage parameter.
ComplexFftInverse.input_imaginary_image
# Property of the outputRealImage parameter.
ComplexFftInverse.output_real_image
# Property of the outputImaginaryImage parameter.
ComplexFftInverse.output_imaginary_image

// Method to launch the command.
execute()

// Command constructor.
ComplexFftInverse()

// Property of the inputRealImage parameter.
ComplexFftInverse.inputRealImage
// Property of the inputImaginaryImage parameter.
ComplexFftInverse.inputImaginaryImage
// Property of the outputRealImage parameter.
ComplexFftInverse.outputRealImage
// Property of the outputImaginaryImage parameter.
ComplexFftInverse.outputImaginaryImage

// Method to launch the command.
Execute()

Parameters

	Description	Type	Supported Values	Default Value
inputRealImage	The real part input image. It must be a floating point image.	Image	Grayscale or Multispectral	nullptr
inputImaginaryImage	The imaginary part input image. This image must have same dimensions and data type as the real input image.	Image	Grayscale or Multispectral	nullptr
outputRealImage	The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.	Image		nullptr
outputImaginaryImage	The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.	Image		nullptr

	Description	Type	Supported Values	Default Value
input_real_image	The real part input image. It must be a floating point image.	image	Grayscale or Multispectral	None
input_imaginary_image	The imaginary part input image. This image must have same dimensions and data type as the real input image.	image	Grayscale or Multispectral	None
output_real_image	The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.	image		None
output_imaginary_image	The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.	image		None

	Description	Type	Supported Values	Default Value
inputRealImage	The real part input image. It must be a floating point image.	Image	Grayscale or Multispectral	null
inputImaginaryImage	The imaginary part input image. This image must have same dimensions and data type as the real input image.	Image	Grayscale or Multispectral	null
outputRealImage	The output real part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.	Image		null
outputImaginaryImage	The output imaginary part image. Its dimensions are forced to the same values as the input. Its data type is forced to floating point.	Image		null

Object Examples

auto polystyrene_float = readVipImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene_float.vip" );

ComplexFftInverse complexFftInverseAlgo;
complexFftInverseAlgo.setInputRealImage( polystyrene_float );
complexFftInverseAlgo.setInputImaginaryImage( polystyrene_float );
complexFftInverseAlgo.execute();

std::cout << "outputRealImage:" << complexFftInverseAlgo.outputRealImage()->toString();
std::cout << "outputImaginaryImage:" << complexFftInverseAlgo.outputImaginaryImage()->toString();

polystyrene_float = imagedev.read_vip_image(imagedev_data.get_image_path("polystyrene_float.vip"))

complex_fft_inverse_algo = imagedev.ComplexFftInverse()
complex_fft_inverse_algo.input_real_image = polystyrene_float
complex_fft_inverse_algo.input_imaginary_image = polystyrene_float
complex_fft_inverse_algo.execute()

print("output_real_image:", str(complex_fft_inverse_algo.output_real_image))
print("output_imaginary_image:", str(complex_fft_inverse_algo.output_imaginary_image))

ImageView polystyrene_float = Data.ReadVipImage( @"Data/images/polystyrene_float.vip" );

ComplexFftInverse complexFftInverseAlgo = new ComplexFftInverse
{
    inputRealImage = polystyrene_float,
    inputImaginaryImage = polystyrene_float
};
complexFftInverseAlgo.Execute();

Console.WriteLine( "outputRealImage:" + complexFftInverseAlgo.outputRealImage.ToString() );
Console.WriteLine( "outputImaginaryImage:" + complexFftInverseAlgo.outputImaginaryImage.ToString() );

Function Examples

auto polystyrene_float = readVipImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene_float.vip" );

auto result = complexFftInverse( polystyrene_float, polystyrene_float );

std::cout << "outputRealImage:" << result.outputRealImage->toString();
std::cout << "outputImaginaryImage:" << result.outputImaginaryImage->toString();

polystyrene_float = imagedev.read_vip_image(imagedev_data.get_image_path("polystyrene_float.vip"))

result_output_real_image, result_output_imaginary_image = imagedev.complex_fft_inverse(polystyrene_float, polystyrene_float)

print("output_real_image:", str(result_output_real_image))
print("output_imaginary_image:", str(result_output_imaginary_image))

ImageView polystyrene_float = Data.ReadVipImage( @"Data/images/polystyrene_float.vip" );

Processing.ComplexFftInverseOutput result = Processing.ComplexFftInverse( polystyrene_float, polystyrene_float );

Console.WriteLine( "outputRealImage:" + result.outputRealImage.ToString() );
Console.WriteLine( "outputImaginaryImage:" + result.outputImaginaryImage.ToString() );