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gen_std_bandpassGenStdBandpassGenStdBandpassgen_std_bandpassgen_std_bandpass🔗

Short description🔗

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

Signature🔗

gen_std_bandpass( out image ImageFilter, real Frequency, real Sigma, string Type, string Norm, string Mode, integer Width, integer 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 )static void HOperatorSet.GenStdBandpass( out HObject imageFilter, HTuple frequency, HTuple sigma, HTuple type, HTuple norm, HTuple mode, HTuple width, HTuple height )def gen_std_bandpass( frequency: float, sigma: float, type: str, norm: str, mode: str, width: int, height: int ) -> HObject

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 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)

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

Description🔗

gen_std_bandpassGenStdBandpass generates a rotationally invariant bandpass filter with the response being determined by the parameters Frequencyfrequencyfrequency and Sigmasigmasigma: Frequencyfrequencyfrequency determines the location of the maximum response with respect to the DC term, while Sigmasigmasigma determines the width of the frequency band that passes the filter. Frequencyfrequencyfrequency and Sigmasigmasigma are specified as a fraction of the maximum (horizontal and vertical) frequency that can be represented in an image of size Widthwidthwidth x Heightheightheight. Frequencyfrequencyfrequency should lie between 0 and 1. For Typetypetype = 'gauss'"gauss", a Gaussian response is generated with Sigmasigmasigma being the standard deviation. For Typetypetype = 'sin'"sin", a sine function is generated with the maximum at Frequencyfrequencyfrequency and the extent Sigmasigmasigma. To achieve a maximum overall efficiency of the filtering operation, the parameter Normnormnorm can be used to specify the normalization factor of the filter. If fft_genericFftGeneric and Normnormnorm \(=\) 'n'"n" is used the normalization in the FFT can be avoided. Modemodemode 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_genericFftGeneric is used, 'dc_edge'"dc_edge" can be used to gain efficiency. If fft_imageFftImage and fft_image_invFftImageInv are used for filtering, Normnormnorm \(=\) 'none'"none" and Modemodemode \(=\) 'dc_center'"dc_center" must be used. If rft_genericRftGeneric is used, Modemodemode \(=\) 'rft'"rft" must be used.

Execution information🔗

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🔗

ImageFilterimageFilterimage_filter (output_object) image → object (real)HObject (real)HImage (real)HObject (real)Hobject * (real)

Bandpass filter as image in the frequency domain.

Frequencyfrequencyfrequency (input_control) real → (real)HTuple (double)HTuple (double)floatHtuple (double)

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

Default: 0.10.1
Suggested values: 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.00.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0
Restriction: Frequency >= 0

Sigmasigmasigma (input_control) real → (real)HTuple (double)HTuple (double)floatHtuple (double)

Bandwidth of the filter (standard deviation).

Default: 0.010.01
Suggested values: 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 1.00.002, 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

Typetypetype (input_control) string → (string)HTuple (HString)HTuple (string)strHtuple (char*)

Filter type.

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

Normnormnorm (input_control) string → (string)HTuple (HString)HTuple (string)strHtuple (char*)

Normalizing factor of the filter.

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

Modemodemode (input_control) string → (string)HTuple (HString)HTuple (string)strHtuple (char*)

Location of the DC term in the frequency domain.

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

Widthwidthwidth (input_control) integer → (integer)HTuple (Hlong)HTuple (int / long)intHtuple (Hlong)

Width of the image (filter).

Default: 512512
Suggested values: 128, 160, 192, 256, 320, 384, 512, 640, 768, 1024, 2048, 4096, 8192128, 160, 192, 256, 320, 384, 512, 640, 768, 1024, 2048, 4096, 8192

Heightheightheight (input_control) integer → (integer)HTuple (Hlong)HTuple (int / long)intHtuple (Hlong)

Height of the image (filter).

Default: 512512
Suggested values: 120, 128, 144, 240, 256, 288, 480, 512, 576, 1024, 2048, 4096, 8192120, 128, 144, 240, 256, 288, 480, 512, 576, 1024, 2048, 4096, 8192

Result🔗

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

Combinations with other operators🔗

Combinations

Possible predecessors

fft_imageFftImage, fft_genericFftGeneric, rft_genericRftGeneric

Possible successors

convol_fftConvolFft

Alternatives

gen_sin_bandpassGenSinBandpass

See also

fft_image_invFftImageInv, gen_gauss_filterGenGaussFilter, gen_mean_filterGenMeanFilter, gen_derivative_filterGenDerivativeFilter, gen_bandpassGenBandpass, gen_bandfilterGenBandfilter, gen_highpassGenHighpass, gen_lowpassGenLowpass

Module🔗

Foundation