gen_bandfiltergen_bandfilterGenBandfilterGenBandfilter (Operator)


gen_bandfiltergen_bandfilterGenBandfilterGenBandfilter — Generate an ideal band filter.


gen_bandfilter( : ImageFilter : MinFrequency, MaxFrequency, Norm, Mode, Width, Height : )

Herror gen_bandfilter(Hobject* ImageFilter, double MinFrequency, double MaxFrequency, const char* Norm, const char* Mode, const Hlong Width, const Hlong Height)

Herror T_gen_bandfilter(Hobject* ImageFilter, const Htuple MinFrequency, const Htuple MaxFrequency, const Htuple Norm, const Htuple Mode, const Htuple Width, const Htuple Height)

void GenBandfilter(HObject* ImageFilter, const HTuple& MinFrequency, const HTuple& MaxFrequency, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

void HImage::GenBandfilter(double MinFrequency, double MaxFrequency, const HString& Norm, const HString& Mode, Hlong Width, Hlong Height)

void HImage::GenBandfilter(double MinFrequency, double MaxFrequency, const char* Norm, const char* Mode, Hlong Width, Hlong Height)

void HImage::GenBandfilter(double MinFrequency, double MaxFrequency, const wchar_t* Norm, const wchar_t* Mode, Hlong Width, Hlong Height)   (Windows only)

static void HOperatorSet.GenBandfilter(out HObject imageFilter, HTuple minFrequency, HTuple maxFrequency, HTuple norm, HTuple mode, HTuple width, HTuple height)

void HImage.GenBandfilter(double minFrequency, double maxFrequency, string norm, string mode, int width, int height)


gen_bandfiltergen_bandfilterGenBandfilterGenBandfilterGenBandfilter generates an ideal band filter in the frequency domain. The parameters MinFrequencyMinFrequencyMinFrequencyMinFrequencyminFrequency and MaxFrequencyMaxFrequencyMaxFrequencyMaxFrequencymaxFrequency determine the cutoff frequencies of the filter as a fraction of the maximum (horizontal and vertical) frequency that can be represented in an image of size WidthWidthWidthWidthwidth x HeightHeightHeightHeightheight, i.e., MinFrequencyMinFrequencyMinFrequencyMinFrequencyminFrequency and MaxFrequencyMaxFrequencyMaxFrequencyMaxFrequencymaxFrequency should lie between 0 and 1. 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_genericFftGenericFftGenericFftGeneric 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_genericFftGenericFftGenericFftGeneric is used, 'dc_edge'"dc_edge""dc_edge""dc_edge""dc_edge" can be used to gain efficiency. If fft_imagefft_imageFftImageFftImageFftImage and fft_image_invfft_image_invFftImageInvFftImageInvFftImageInv 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_genericRftGenericRftGenericRftGeneric is used, ModeModeModeModemode = 'rft'"rft""rft""rft""rft" must be used. The resulting image contains an annulus with the value 0, and a value determined by the normalization outside of this annulus.

Execution Information


ImageFilterImageFilterImageFilterImageFilterimageFilter (output_object)  image objectHImageHImageHobject * (real)

Band filter in the frequency domain.

MinFrequencyMinFrequencyMinFrequencyMinFrequencyminFrequency (input_control)  real HTupleHTupleHtuple (real) (double) (double) (double)

Minimum 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: MinFrequency >= 0

MaxFrequencyMaxFrequencyMaxFrequencyMaxFrequencymaxFrequency (input_control)  real HTupleHTupleHtuple (real) (double) (double) (double)

Maximum frequency.

Default value: 0.2

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: MaxFrequency >= 0 && MaxFrequency >= MinFrequency

NormNormNormNormnorm (input_control)  string HTupleHTupleHtuple (string) (string) (HString) (char*)

Normalizing factor of the filter.

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

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

ModeModeModeModemode (input_control)  string HTupleHTupleHtuple (string) (string) (HString) (char*)

Location of the DC term in the frequency domain.

Default value: '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 HTupleHTupleHtuple (integer) (int / long) (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

HeightHeightHeightHeightheight (input_control)  integer HTupleHTupleHtuple (integer) (int / long) (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_bandfiltergen_bandfilterGenBandfilterGenBandfilterGenBandfilter returns 2 (H_MSG_TRUE) if all parameters are correct. If necessary, an exception is raised.

Possible Successors



gen_circlegen_circleGenCircleGenCircleGenCircle, paint_regionpaint_regionPaintRegionPaintRegionPaintRegion

See also

gen_highpassgen_highpassGenHighpassGenHighpassGenHighpass, gen_lowpassgen_lowpassGenLowpassGenLowpassGenLowpass, gen_bandpassgen_bandpassGenBandpassGenBandpassGenBandpass, gen_gauss_filtergen_gauss_filterGenGaussFilterGenGaussFilterGenGaussFilter, gen_mean_filtergen_mean_filterGenMeanFilterGenMeanFilterGenMeanFilter, gen_derivative_filtergen_derivative_filterGenDerivativeFilterGenDerivativeFilterGenDerivativeFilter