convol_fftconvol_fftConvolFftConvolFftconvol_fft（算子）

名称

convol_fftconvol_fftConvolFftConvolFftconvol_fft — 在频域中使用滤波器对图像进行卷积。

签名

convol_fft(ImageFFT, ImageFilter : ImageConvol : : )

描述

As part of calculating the convolution of an image with a filter image, convol_fftconvol_fftConvolFftConvolFftConvolFftconvol_fft multiplies the Fourier transform of an image ImageFFTImageFFTImageFFTImageFFTimageFFTimage_fft with the Fourier transform of a second image ImageFilterImageFilterImageFilterImageFilterimageFilterimage_filter, which serves as the filter.

According to the convolution theorem, the non-normalized convolution of two images in pixel space can be obtained in three steps:

Transforming the images into frequency space using a Fourier transform (see, e.g., fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic).
Multiplying one transformed image with the transformed filter image (pixel-wise).
Transforming the result back into pixel space using an inverse Fourier transform (see, e.g., fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic).

算子 convol_fftconvol_fftConvolFftConvolFftConvolFftconvol_fft is used to perform the second step, i.e., ImageFFTImageFFTImageFFTImageFFTimageFFTimage_fft is pixel-wise multiplied with ImageFilterImageFilterImageFilterImageFilterimageFilterimage_filter。

注意

The filtering is always done on the entire image, i.e., the domain of the image is ignored.

执行信息

多线程类型：可重入（与非独占算子并行运行）。
多线程作用域：全局（可从任何线程调用）。
在元组级别上自动并行化。
在通道级别上自动并行化。

参数

ImageFFTImageFFTImageFFTImageFFTimageFFTimage_fft (输入对象) (multichannel-)image(-array) → object (complex)

Complex input image.

ImageFilterImageFilterImageFilterImageFilterimageFilterimage_filter (输入对象) (multichannel-)image → object (real / complex)

Filter in frequency domain.

ImageConvolImageConvolImageConvolImageConvolimageConvolimage_convol (输出对象) image(-array) → object (complex)

Result in the frequency domain.

示例（HDevelop）

gen_highpass(Highpass,0.2,'n','dc_edge',Width,Height)
fft_generic(Image,ImageFFT,'to_freq',-1,'none','dc_edge','complex')
convol_fft(ImageFFT,Highpass,ImageConvol)
fft_generic(ImageConvol,ImageResult,'from_freq',1,'none','dc_edge','byte')

结果

convol_fftconvol_fftConvolFftConvolFftConvolFftconvol_fft 在所有参数正确时返回 2 ( H_MSG_TRUE )。当输入为空时，可设置行为通过算子 set_system(::'no_object_result',<Result>:)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>)。如有必要，则抛出异常。

可能的前趋

fft_imagefft_imageFftImageFftImageFftImagefft_image, fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic, rft_genericrft_genericRftGenericRftGenericRftGenericrft_generic, gen_highpassgen_highpassGenHighpassGenHighpassGenHighpassgen_highpass, gen_lowpassgen_lowpassGenLowpassGenLowpassGenLowpassgen_lowpass, gen_bandpassgen_bandpassGenBandpassGenBandpassGenBandpassgen_bandpass, gen_bandfiltergen_bandfilterGenBandfilterGenBandfilterGenBandfiltergen_bandfilter

可能的后继

power_bytepower_bytePowerBytePowerBytePowerBytepower_byte, power_realpower_realPowerRealPowerRealPowerRealpower_real, power_lnpower_lnPowerLnPowerLnPowerLnpower_ln, fft_image_invfft_image_invFftImageInvFftImageInvFftImageInvfft_image_inv, fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic, rft_genericrft_genericRftGenericRftGenericRftGenericrft_generic

替代

convol_gaborconvol_gaborConvolGaborConvolGaborConvolGaborconvol_gabor

另见

gen_gaborgen_gaborGenGaborGenGaborGenGaborgen_gabor, gen_highpassgen_highpassGenHighpassGenHighpassGenHighpassgen_highpass, gen_lowpassgen_lowpassGenLowpassGenLowpassGenLowpassgen_lowpass, gen_bandpassgen_bandpassGenBandpassGenBandpassGenBandpassgen_bandpass, convol_gaborconvol_gaborConvolGaborConvolGaborConvolGaborconvol_gabor, fft_image_invfft_image_invFftImageInvFftImageInvFftImageInvfft_image_inv

模块

基础

算子