Operator Reference

HALCON Operator Reference / Filters / FFT
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gen_std_bandpassgen_std_bandpassGenStdBandpassGenStdBandpassgen_std_bandpass (Operator)

gen_std_bandpassgen_std_bandpassGenStdBandpassGenStdBandpassgen_std_bandpass — Generate a bandpass filter with Gaussian or sinusoidal shape.

Signature

gen_std_bandpass( : ImageFilter : Frequency, Sigma, Type, Norm, Mode, Width, Height : )

Herror gen_std_bandpass(Hobject* ImageFilter, double Frequency, double Sigma, const char* Type, const char* Norm, const char* Mode, const Hlong Width, const Hlong Height)

Herror T_gen_std_bandpass(Hobject* ImageFilter, const Htuple Frequency, const Htuple Sigma, const Htuple Type, const Htuple Norm, const Htuple Mode, const Htuple Width, const Htuple Height)

void GenStdBandpass(HObject* ImageFilter, const HTuple& Frequency, const HTuple& Sigma, const HTuple& Type, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

void HImage::GenStdBandpass(double Frequency, double Sigma, const HString& Type, const HString& Norm, const HString& Mode, Hlong Width, Hlong Height)

void HImage::GenStdBandpass(double Frequency, double Sigma, const char* Type, const char* Norm, const char* Mode, Hlong Width, Hlong Height)

void HImage::GenStdBandpass(double Frequency, double Sigma, const wchar_t* Type, const wchar_t* Norm, const wchar_t* Mode, Hlong Width, Hlong Height)   ( Windows only)

static void HOperatorSet.GenStdBandpass(out HObject imageFilter, HTuple frequency, HTuple sigma, HTuple type, HTuple norm, HTuple mode, HTuple width, HTuple height)

void HImage.GenStdBandpass(double frequency, double sigma, string type, string norm, string mode, int width, int height)

def gen_std_bandpass(frequency: float, sigma: float, type: str, norm: str, mode: str, width: int, height: int) -> HObject

Description

gen_std_bandpassgen_std_bandpassGenStdBandpassGenStdBandpassgen_std_bandpass generates a rotationally invariant bandpass filter with the response being determined by the parameters FrequencyFrequencyFrequencyfrequencyfrequency and SigmaSigmaSigmasigmasigma: FrequencyFrequencyFrequencyfrequencyfrequency determines the location of the maximum response with respect to the DC term, while SigmaSigmaSigmasigmasigma determines the width of the frequency band that passes the filter. FrequencyFrequencyFrequencyfrequencyfrequency and SigmaSigmaSigmasigmasigma are specified as a fraction of the maximum (horizontal and vertical) frequency that can be represented in an image of size WidthWidthWidthwidthwidth x HeightHeightHeightheightheight. FrequencyFrequencyFrequencyfrequencyfrequency should lie between 0 and 1. For TypeTypeTypetypetype = 'gauss'"gauss""gauss""gauss""gauss", a Gaussian response is generated with SigmaSigmaSigmasigmasigma being the standard deviation. For TypeTypeTypetypetype = 'sin'"sin""sin""sin""sin", a sine function is generated with the maximum at FrequencyFrequencyFrequencyfrequencyfrequency and the extent SigmaSigmaSigmasigmasigma. To achieve a maximum overall efficiency of the filtering operation, the parameter NormNormNormnormnorm can be used to specify the normalization factor of the filter. If fft_genericfft_genericFftGenericFftGenericfft_generic and NormNormNormnormnorm = 'n'"n""n""n""n" is used the normalization in the FFT can be avoided. ModeModeModemodemode can be used to determine where the DC term of the filter lies or whether the filter should be used in the real-valued FFT. If fft_genericfft_genericFftGenericFftGenericfft_generic is used, 'dc_edge'"dc_edge""dc_edge""dc_edge""dc_edge" can be used to gain efficiency. If fft_imagefft_imageFftImageFftImagefft_image and fft_image_invfft_image_invFftImageInvFftImageInvfft_image_inv are used for filtering, NormNormNormnormnorm = 'none'"none""none""none""none" and ModeModeModemodemode = 'dc_center'"dc_center""dc_center""dc_center""dc_center" must be used. If rft_genericrft_genericRftGenericRftGenericrft_generic is used, ModeModeModemodemode = 'rft'"rft""rft""rft""rft" must be used.

Execution Information

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).
  • Multithreading scope: global (may be called from any thread).
  • Processed without parallelization.

Parameters

ImageFilterImageFilterImageFilterimageFilterimage_filter (output_object)  image → objectHImageHObjectHObjectHobject * (real)

Bandpass filter as image in the frequency domain.

FrequencyFrequencyFrequencyfrequencyfrequency (input_control)  real → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Distance of the filter's maximum from the DC term.

Default: 0.1

Suggested values: 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0

Restriction: Frequency >= 0

SigmaSigmaSigmasigmasigma (input_control)  real → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Bandwidth of the filter (standard deviation).

Default: 0.01

Suggested values: 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 1.0

Restriction: Sigma >= 0

TypeTypeTypetypetype (input_control)  string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Filter type.

Default: 'sin' "sin" "sin" "sin" "sin"

List of values: 'gauss'"gauss""gauss""gauss""gauss", 'sin'"sin""sin""sin""sin"

NormNormNormnormnorm (input_control)  string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Normalizing factor of the filter.

Default: 'none' "none" "none" "none" "none"

List of values: 'n'"n""n""n""n", 'none'"none""none""none""none"

ModeModeModemodemode (input_control)  string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Location of the DC term in the frequency domain.

Default: 'dc_center' "dc_center" "dc_center" "dc_center" "dc_center"

List of values: 'dc_center'"dc_center""dc_center""dc_center""dc_center", 'dc_edge'"dc_edge""dc_edge""dc_edge""dc_edge", 'rft'"rft""rft""rft""rft"

WidthWidthWidthwidthwidth (input_control)  integer → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Width of the image (filter).

Default: 512

Suggested values: 128, 160, 192, 256, 320, 384, 512, 640, 768, 1024, 2048, 4096, 8192

HeightHeightHeightheightheight (input_control)  integer → HTupleintHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Height of the image (filter).

Default: 512

Suggested values: 120, 128, 144, 240, 256, 288, 480, 512, 576, 1024, 2048, 4096, 8192

Result

gen_std_bandpassgen_std_bandpassGenStdBandpassGenStdBandpassgen_std_bandpass returns 2 ( H_MSG_TRUE) if all parameters are correct. If necessary, an exception is raised.

Possible Predecessors

fft_imagefft_imageFftImageFftImagefft_image, fft_genericfft_genericFftGenericFftGenericfft_generic, rft_genericrft_genericRftGenericRftGenericrft_generic

Possible Successors

convol_fftconvol_fftConvolFftConvolFftconvol_fft

Alternatives

gen_sin_bandpassgen_sin_bandpassGenSinBandpassGenSinBandpassgen_sin_bandpass

See also

fft_image_invfft_image_invFftImageInvFftImageInvfft_image_inv, gen_gauss_filtergen_gauss_filterGenGaussFilterGenGaussFiltergen_gauss_filter, gen_mean_filtergen_mean_filterGenMeanFilterGenMeanFiltergen_mean_filter, gen_derivative_filtergen_derivative_filterGenDerivativeFilterGenDerivativeFiltergen_derivative_filter, gen_bandpassgen_bandpassGenBandpassGenBandpassgen_bandpass, gen_bandfiltergen_bandfilterGenBandfilterGenBandfiltergen_bandfilter, gen_highpassgen_highpassGenHighpassGenHighpassgen_highpass, gen_lowpassgen_lowpassGenLowpassGenLowpassgen_lowpass

Module

Foundation

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