gen_gauss_filtergen_gauss_filterGenGaussFilterGenGaussFiltergen_gauss_filter (Operator)
Name
gen_gauss_filtergen_gauss_filterGenGaussFilterGenGaussFiltergen_gauss_filter — Generate a Gaussian filter in the frequency domain.
Signature
Herror gen_gauss_filter(Hobject* ImageGauss, double Sigma1, double Sigma2, double Phi, const char* Norm, const char* Mode, const Hlong Width, const Hlong Height)
Herror T_gen_gauss_filter(Hobject* ImageGauss, const Htuple Sigma1, const Htuple Sigma2, const Htuple Phi, const Htuple Norm, const Htuple Mode, const Htuple Width, const Htuple Height)
void GenGaussFilter(HObject* ImageGauss, const HTuple& Sigma1, const HTuple& Sigma2, const HTuple& Phi, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)
void HImage::GenGaussFilter(double Sigma1, double Sigma2, double Phi, const HString& Norm, const HString& Mode, Hlong Width, Hlong Height)
void HImage::GenGaussFilter(double Sigma1, double Sigma2, double Phi, const char* Norm, const char* Mode, Hlong Width, Hlong Height)
void HImage::GenGaussFilter(double Sigma1, double Sigma2, double Phi, const wchar_t* Norm, const wchar_t* Mode, Hlong Width, Hlong Height)
(
Windows only)
static void HOperatorSet.GenGaussFilter(out HObject imageGauss, HTuple sigma1, HTuple sigma2, HTuple phi, HTuple norm, HTuple mode, HTuple width, HTuple height)
void HImage.GenGaussFilter(double sigma1, double sigma2, double phi, string norm, string mode, int width, int height)
Description
gen_gauss_filtergen_gauss_filterGenGaussFilterGenGaussFiltergen_gauss_filter generates a (possibly anisotropic) Gaussian
filter in the frequency domain. The standard deviations (i.e., the
amount of smoothing) of the Gaussian in the spatial domain are
determined by Sigma1Sigma1Sigma1sigma1sigma_1 and Sigma2Sigma2Sigma2sigma2sigma_2. Sigma1Sigma1Sigma1sigma1sigma_1
is the standard deviation in the principal direction of the filter
in the spatial domain determined by the angle PhiPhiPhiphiphi. 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
ImageGaussImageGaussImageGaussimageGaussimage_gauss (output_object) image → objectHImageHObjectHObjectHobject * (real)
Gaussian filter as image in the frequency domain.
Sigma1Sigma1Sigma1sigma1sigma_1 (input_control) real → HTuplefloatHTupleHtuple (real) (double) (double) (double)
Standard deviation of the Gaussian in the
principal direction of the filter in the
spatial domain.
Default:
1.0
Suggested values:
0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0
Restriction:
Sigma1 >= 0
Sigma2Sigma2Sigma2sigma2sigma_2 (input_control) real → HTuplefloatHTupleHtuple (real) (double) (double) (double)
Standard deviation of the Gaussian perpendicular
to the principal direction of the filter in the
spatial domain.
Default:
1.0
Suggested values:
0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0
Restriction:
Sigma2 >= 0
PhiPhiPhiphiphi (input_control) angle.rad → HTuplefloatHTupleHtuple (real) (double) (double) (double)
Principal direction of the filter in the
spatial domain.
Default:
0.0
Suggested values:
0.0, 0.523599, 0.785398, 1.047198, 1.570796, 2.094395, 2.356194, 2.617994, 3.141593
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
Example (HDevelop)
* Generate a smoothed derivative filter.
gen_gauss_filter (ImageGauss, Sigma, Sigma, 0, 'n', 'dc_edge', 512, 512)
convert_image_type (ImageGauss, ImageGaussComplex, 'complex')
gen_derivative_filter (ImageDerivX, 'x', 1, 'none', 'dc_edge', 512, 512)
mult_image (ImageGaussComplex, ImageDerivX, ImageDerivXGauss, 1, 0)
* Filter an image with the smoothed derivative filter.
fft_generic (Image, ImageFFT, 'to_freq', -1, 'none', 'dc_edge', 'complex')
convol_fft (ImageFFT, ImageDerivXGauss, Filtered)
fft_generic (Filtered, ImageX, 'from_freq', 1, 'none', 'dc_edge', 'real')
Result
gen_gauss_filtergen_gauss_filterGenGaussFilterGenGaussFiltergen_gauss_filter 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
See also
fft_image_invfft_image_invFftImageInvFftImageInvfft_image_inv,
gen_mean_filtergen_mean_filterGenMeanFilterGenMeanFiltergen_mean_filter,
gen_derivative_filtergen_derivative_filterGenDerivativeFilterGenDerivativeFiltergen_derivative_filter,
gen_lowpassgen_lowpassGenLowpassGenLowpassgen_lowpass,
gen_bandpassgen_bandpassGenBandpassGenBandpassgen_bandpass,
gen_bandfiltergen_bandfilterGenBandfilterGenBandfiltergen_bandfilter,
gen_highpassgen_highpassGenHighpassGenHighpassgen_highpass
Module
Foundation