Operator Reference

HALCON Operator Reference / Filters / FFT

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ClassesClasses | | Operators

power_lnpower_lnPowerLnPowerLnpower_ln (Operator)

power_lnpower_lnPowerLnPowerLnpower_ln — Return the power spectrum of a complex image.

Signature

power_ln(Image : ImageResult : : )

Herror power_ln(const Hobject Image, Hobject* ImageResult)

Herror T_power_ln(const Hobject Image, Hobject* ImageResult)

void PowerLn(const HObject& Image, HObject* ImageResult)

HImage HImage::PowerLn() const

static void HOperatorSet.PowerLn(HObject image, out HObject imageResult)

HImage HImage.PowerLn()

def power_ln(image: HObject) -> HObject

Description

power_lnpower_lnPowerLnPowerLnpower_ln computes the power spectrum from the real and imaginary parts of a Fourier-transformed image (see fft_imagefft_imageFftImageFftImagefft_image), i.e., the modulus of the frequencies. Additionally, the natural logarithm is applied to the result. The result image is of type real. The following formula is used:

Execution Information

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Automatically parallelized on tuple level.
• Automatically parallelized on channel level.
• Automatically parallelized on domain level.

Parameters

ImageImageImageimageimage (input_object)  (multichannel-)image(-array) → objectHImageHObjectHObjectHobject (complex)

Input image in frequency domain.

ImageResultImageResultImageResultimageResultimage_result (output_object)  image(-array) → objectHImageHObjectHObjectHobject * (real)

Power spectrum of the input image.

Example (C)

read_image(&Image,"monkey");
disp_image(Image,WindowHandle);
fft_image(Image,&FFT);
power_ln(FFT,&Power);
disp_image(Power,WindowHandle);

Result

power_lnpower_lnPowerLnPowerLnpower_ln returns 2 ( H_MSG_TRUE) if the image is of correct type. If the input is empty the behavior can be set via set_system(::'no_object_result',<Result>:)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

fft_imagefft_imageFftImageFftImagefft_image, fft_genericfft_genericFftGenericFftGenericfft_generic, rft_genericrft_genericRftGenericRftGenericrft_generic, convol_fftconvol_fftConvolFftConvolFftconvol_fft, convol_gaborconvol_gaborConvolGaborConvolGaborconvol_gabor

Possible Successors

disp_imagedisp_imageDispImageDispImagedisp_image, convert_image_typeconvert_image_typeConvertImageTypeConvertImageTypeconvert_image_type, scale_imagescale_imageScaleImageScaleImagescale_image

Alternatives

abs_imageabs_imageAbsImageAbsImageabs_image, convert_image_typeconvert_image_typeConvertImageTypeConvertImageTypeconvert_image_type, power_realpower_realPowerRealPowerRealpower_real, power_bytepower_bytePowerBytePowerBytepower_byte

See also

fft_imagefft_imageFftImageFftImagefft_image, fft_genericfft_genericFftGenericFftGenericfft_generic, rft_genericrft_genericRftGenericRftGenericrft_generic

Module

Foundation

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ClassesClasses | | Operators