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gen_lowpassgen_lowpassGenLowpassgen_lowpassGenLowpassGenLowpass (Operator)


gen_lowpassgen_lowpassGenLowpassgen_lowpassGenLowpassGenLowpass — Generate an ideal lowpass filter.


gen_lowpass( : ImageLowpass : Frequency, Norm, Mode, Width, Height : )

Herror gen_lowpass(Hobject* ImageLowpass, double Frequency, const char* Norm, const char* Mode, const Hlong Width, const Hlong Height)

Herror T_gen_lowpass(Hobject* ImageLowpass, const Htuple Frequency, const Htuple Norm, const Htuple Mode, const Htuple Width, const Htuple Height)

Herror gen_lowpass(Hobject* ImageLowpass, const HTuple& Frequency, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

HImage HImage::GenLowpass(const HTuple& Frequency, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

void GenLowpass(HObject* ImageLowpass, const HTuple& Frequency, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

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

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

void HOperatorSetX.GenLowpass(
[out] IHUntypedObjectX*ImageLowpass, [in] VARIANT Frequency, [in] VARIANT Norm, [in] VARIANT Mode, [in] VARIANT Width, [in] VARIANT Height)

void HImageX.GenLowpass(
[in] double Frequency, [in] BSTR Norm, [in] BSTR Mode, [in] Hlong Width, [in] Hlong Height)

static void HOperatorSet.GenLowpass(out HObject imageLowpass, HTuple frequency, HTuple norm, HTuple mode, HTuple width, HTuple height)

void HImage.GenLowpass(double frequency, string norm, string mode, int width, int height)


gen_lowpassgen_lowpassGenLowpassgen_lowpassGenLowpassGenLowpass generates an ideal lowpass filter in the frequency domain. The parameter FrequencyFrequencyFrequencyFrequencyFrequencyfrequency determines the cutoff frequency of the filter as a fraction of the maximum (horizontal and vertical) frequency that can be represented in an image of size WidthWidthWidthWidthWidthwidth x HeightHeightHeightHeightHeightheight, i.e., FrequencyFrequencyFrequencyFrequencyFrequencyfrequency should lie between 0 and 1. To achieve a maximum overall efficiency of the filtering operation, the parameter NormNormNormNormNormnorm can be used to specify the normalization factor of the filter. If fft_genericfft_genericFftGenericfft_genericFftGenericFftGeneric and NormNormNormNormNormnorm = 'n'"n""n""n""n""n" is used the normalization in the FFT can be avoided. ModeModeModeModeModemode 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_genericFftGenericfft_genericFftGenericFftGeneric is used, 'dc_edge'"dc_edge""dc_edge""dc_edge""dc_edge""dc_edge" can be used to gain efficiency. If fft_imagefft_imageFftImagefft_imageFftImageFftImage and fft_image_invfft_image_invFftImageInvfft_image_invFftImageInvFftImageInv are used for filtering, NormNormNormNormNormnorm = 'none'"none""none""none""none""none" and ModeModeModeModeModemode = 'dc_center'"dc_center""dc_center""dc_center""dc_center""dc_center" must be used. If rft_genericrft_genericRftGenericrft_genericRftGenericRftGeneric is used, ModeModeModeModeModemode = 'rft'"rft""rft""rft""rft""rft" must be used. The resulting image has an inner part with the value set to the normalization factor, and an outer part with the value 0.



ImageLowpassImageLowpassImageLowpassImageLowpassImageLowpassimageLowpass (output_object)  image objectHImageHImageHImageHImageXHobject * (real)

Lowpass filter in the frequency domain.

FrequencyFrequencyFrequencyFrequencyFrequencyfrequency (input_control)  real HTupleHTupleHTupleVARIANTHtuple (real) (double) (double) (double) (double) (double)

Cutoff frequency.

Default value: 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

NormNormNormNormNormnorm (input_control)  string HTupleHTupleHTupleVARIANTHtuple (string) (string) (HString) (char*) (BSTR) (char*)

Normalizing factor of the filter.

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

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

ModeModeModeModeModemode (input_control)  string HTupleHTupleHTupleVARIANTHtuple (string) (string) (HString) (char*) (BSTR) (char*)

Location of the DC term in the frequency domain.

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

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

WidthWidthWidthWidthWidthwidth (input_control)  integer HTupleHTupleHTupleVARIANTHtuple (integer) (int / long) (Hlong) (Hlong) (Hlong) (Hlong)

Width of the image (filter).

Default value: 512

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

HeightHeightHeightHeightHeightheight (input_control)  integer HTupleHTupleHTupleVARIANTHtuple (integer) (int / long) (Hlong) (Hlong) (Hlong) (Hlong)

Height of the image (filter).

Default value: 512

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

Example (HDevelop)

* Filtering with maximum efficiency with fft_generic.


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

Possible Successors


See also

gen_highpassgen_highpassGenHighpassgen_highpassGenHighpassGenHighpass, gen_bandpassgen_bandpassGenBandpassgen_bandpassGenBandpassGenBandpass, gen_bandfiltergen_bandfilterGenBandfiltergen_bandfilterGenBandfilterGenBandfilter, gen_gauss_filtergen_gauss_filterGenGaussFiltergen_gauss_filterGenGaussFilterGenGaussFilter, gen_mean_filtergen_mean_filterGenMeanFiltergen_mean_filterGenMeanFilterGenMeanFilter, gen_derivative_filtergen_derivative_filterGenDerivativeFiltergen_derivative_filterGenDerivativeFilterGenDerivativeFilter



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