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gen_derivative_filtergen_derivative_filterGenDerivativeFiltergen_derivative_filterGenDerivativeFilterGenDerivativeFilter (Operator)

Name

gen_derivative_filtergen_derivative_filterGenDerivativeFiltergen_derivative_filterGenDerivativeFilterGenDerivativeFilter — Generate a derivative filter in the frequency domain.

Signature

gen_derivative_filter( : ImageDerivative : Derivative, Exponent, Norm, Mode, Width, Height : )

Herror gen_derivative_filter(Hobject* ImageDerivative, const char* Derivative, const Hlong Exponent, const char* Norm, const char* Mode, const Hlong Width, const Hlong Height)

Herror T_gen_derivative_filter(Hobject* ImageDerivative, const Htuple Derivative, const Htuple Exponent, const Htuple Norm, const Htuple Mode, const Htuple Width, const Htuple Height)

Herror gen_derivative_filter(Hobject* ImageDerivative, const HTuple& Derivative, const HTuple& Exponent, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

HImage HImage::GenDerivativeFilter(const HTuple& Derivative, const HTuple& Exponent, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

void GenDerivativeFilter(HObject* ImageDerivative, const HTuple& Derivative, const HTuple& Exponent, const HTuple& Norm, const HTuple& Mode, const HTuple& Width, const HTuple& Height)

void HImage::GenDerivativeFilter(const HString& Derivative, Hlong Exponent, const HString& Norm, const HString& Mode, Hlong Width, Hlong Height)

void HImage::GenDerivativeFilter(const char* Derivative, Hlong Exponent, const char* Norm, const char* Mode, Hlong Width, Hlong Height)

void HOperatorSetX.GenDerivativeFilter(
[out] IHUntypedObjectX*ImageDerivative, [in] VARIANT Derivative, [in] VARIANT Exponent, [in] VARIANT Norm, [in] VARIANT Mode, [in] VARIANT Width, [in] VARIANT Height)

void HImageX.GenDerivativeFilter(
[in] BSTR Derivative, [in] Hlong Exponent, [in] BSTR Norm, [in] BSTR Mode, [in] Hlong Width, [in] Hlong Height)

static void HOperatorSet.GenDerivativeFilter(out HObject imageDerivative, HTuple derivative, HTuple exponent, HTuple norm, HTuple mode, HTuple width, HTuple height)

void HImage.GenDerivativeFilter(string derivative, int exponent, string norm, string mode, int width, int height)

Description

gen_derivative_filtergen_derivative_filterGenDerivativeFiltergen_derivative_filterGenDerivativeFilterGenDerivativeFilter generates a derivative filter in the frequency domain. The derivative to be computed is determined by DerivativeDerivativeDerivativeDerivativeDerivativederivative. ExponentExponentExponentExponentExponentexponent specifies the exponent used in the reverse transform. It must be set to the same value that is used in fft_genericfft_genericFftGenericfft_genericFftGenericFftGeneric. If fft_image_invfft_image_invFftImageInvfft_image_invFftImageInvFftImageInv is used in the reverse transform, ExponentExponentExponentExponentExponentexponent = 1 must be used. However, since the derivative image typically contains negative values, fft_genericfft_genericFftGenericfft_genericFftGenericFftGeneric should always be used for the reverse transform. 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.

Parallelization

Parameters

ImageDerivativeImageDerivativeImageDerivativeImageDerivativeImageDerivativeimageDerivative (output_object)  image objectHImageHImageHImageHImageXHobject * (complex)

Derivative filter as image in the frequency domain.

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

Derivative to be computed.

Default value: 'x' "x" "x" "x" "x" "x"

Suggested values: 'x'"x""x""x""x""x", 'y'"y""y""y""y""y", 'xx'"xx""xx""xx""xx""xx", 'xy'"xy""xy""xy""xy""xy", 'yy'"yy""yy""yy""yy""yy", 'xxx'"xxx""xxx""xxx""xxx""xxx", 'xxy'"xxy""xxy""xxy""xxy""xxy", 'xyy'"xyy""xyy""xyy""xyy""xyy", 'yyy'"yyy""yyy""yyy""yyy""yyy"

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

Exponent used in the reverse transform.

Default value: 1

Suggested values: -1, 1

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)

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

Possible Predecessors

fft_imagefft_imageFftImagefft_imageFftImageFftImage, fft_genericfft_genericFftGenericfft_genericFftGenericFftGeneric, rft_genericrft_genericRftGenericrft_genericRftGenericRftGeneric

Possible Successors

convol_fftconvol_fftConvolFftconvol_fftConvolFftConvolFft

See also

fft_image_invfft_image_invFftImageInvfft_image_invFftImageInvFftImageInv, gen_gauss_filtergen_gauss_filterGenGaussFiltergen_gauss_filterGenGaussFilterGenGaussFilter, gen_mean_filtergen_mean_filterGenMeanFiltergen_mean_filterGenMeanFilterGenMeanFilter, gen_lowpassgen_lowpassGenLowpassgen_lowpassGenLowpassGenLowpass, gen_bandpassgen_bandpassGenBandpassgen_bandpassGenBandpassGenBandpass, gen_bandfiltergen_bandfilterGenBandfiltergen_bandfilterGenBandfilterGenBandfilter, gen_highpassgen_highpassGenHighpassgen_highpassGenHighpassGenHighpass

Module

Foundation


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