correlation_fftcorrelation_fftCorrelationFftCorrelationFftcorrelation_fft（算子）

名称

correlation_fftcorrelation_fftCorrelationFftCorrelationFftcorrelation_fft — 在频域内将一个图像与另一个图像的复共轭相乘。

签名

描述

As part of calculating the correlation between two images, correlation_fftcorrelation_fftCorrelationFftCorrelationFftCorrelationFftcorrelation_fft multiplies the Fourier transform of the first image ImageFFT1ImageFFT1ImageFFT1ImageFFT1imageFFT1image_fft1 with the complex conjugate of the Fourier-transformed second image ImageFFT2ImageFFT2ImageFFT2ImageFFT2imageFFT2image_fft2。

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

1. Transforming the images into frequency space using a Fourier transform (see, e.g., fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic).

2. Multiplying one transformed image with the complex conjugate of the other transformed image (pixel-wise).

3. Transforming the result back into pixel space using an inverse Fourier transform (see, e.g., fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic).

算子 correlation_fftcorrelation_fftCorrelationFftCorrelationFftCorrelationFftcorrelation_fft is used to perform the second step, i.e., ImageFFT1ImageFFT1ImageFFT1ImageFFT1imageFFT1image_fft1 is pixel-wise multiplied with the complex conjugate of ImageFFT2ImageFFT2ImageFFT2ImageFFT2imageFFT2image_fft2。

It should be noted that in order to achieve a correct scaling of the correlation in the spatial domain, the operators fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic or rft_genericrft_genericRftGenericRftGenericRftGenericrft_generic with NormNormNormNormnormnorm = 'none'"none""none""none""none""none" must be used for the forward transform (step 1) and fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic or rft_genericrft_genericRftGenericRftGenericRftGenericrft_generic with NormNormNormNormnormnorm = 'n'"n""n""n""n""n" for the reverse transform (step 3). If ImageFFT1ImageFFT1ImageFFT1ImageFFT1imageFFT1image_fft1 and ImageFFT2ImageFFT2ImageFFT2ImageFFT2imageFFT2image_fft2 contain the same number of images, the corresponding images are multiplied pairwise. Otherwise, ImageFFT2ImageFFT2ImageFFT2ImageFFT2imageFFT2image_fft2 must contain only one single image. In this case, the multiplication is performed for each image of ImageFFT1ImageFFT1ImageFFT1ImageFFT1imageFFT1image_fft1 with ImageFFT2ImageFFT2ImageFFT2ImageFFT2imageFFT2image_fft2。

注意

The filtering is always performed 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

示例（HDevelop）

* Compute the auto-correlation of an image.
get_image_size(Image,Width,Height)
rft_generic(Image,ImageFFT,'to_freq','none','complex',Width)
correlation_fft(ImageFFT,ImageFFT,Correlation)
rft_generic(Correlation,AutoCorrelation,'from_freq','n','real',Width)

结果

correlation_fftcorrelation_fftCorrelationFftCorrelationFftCorrelationFftcorrelation_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_genericfft_genericFftGenericFftGenericFftGenericfft_generic, fft_imagefft_imageFftImageFftImageFftImagefft_image, rft_genericrft_genericRftGenericRftGenericRftGenericrft_generic

可能的后继

fft_genericfft_genericFftGenericFftGenericFftGenericfft_generic, fft_image_invfft_image_invFftImageInvFftImageInvFftImageInvfft_image_inv, rft_genericrft_genericRftGenericRftGenericRftGenericrft_generic

替代

phase_correlation_fftphase_correlation_fftPhaseCorrelationFftPhaseCorrelationFftPhaseCorrelationFftphase_correlation_fft

模块

基础