Name
gen_lowpassgen_lowpassGenLowpassgen_lowpassGenLowpassGenLowpass — Generate an ideal lowpass filter.
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)
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)
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.
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Processed without parallelization.
Lowpass filter in the frequency domain.
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
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"
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"
Width of the image (filter).
Default value: 512
List of values: 128, 160, 192, 256, 320, 384, 512, 640, 768, 1024, 2048, 4096, 8192
Height of the image (filter).
Default value: 512
List of values: 120, 128, 144, 240, 256, 288, 480, 512, 576, 1024, 2048, 4096, 8192
* Filtering with maximum efficiency with fft_generic.
gen_lowpass(Lowpass,0.2,'n','dc_edge',Width,Height)
fft_generic(Image,ImageFFT,'to_freq',-1,'none','dc_edge','complex')
convol_fft(ImageFFT,Lowpass,ImageConvol)
fft_generic(ImageConvol,ImageResult,'from_freq',1,'none','dc_edge','byte')
gen_lowpassgen_lowpassGenLowpassgen_lowpassGenLowpassGenLowpass returns 2 (H_MSG_TRUE) if all parameters are correct.
If necessary, an exception is raised.
convol_fftconvol_fftConvolFftconvol_fftConvolFftConvolFft
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
Foundation