phase_correlation_fft — Compute the phase correlation of two images in the frequency domain.
phase_correlation_fft calculates the phase correlation of the Fourier-transformed input images in the frequency domain. The phase correlation is calculated by multiplying ImageFFT1 with the complex conjugate of ImageFFT2 and dividing by the absolute value of this product. It should be noted that in order to achieve a correct scaling of the phase correlation in the spatial domain, the operators fft_generic or rft_generic with Norm = 'none' must be used for the forward transform and fft_generic or rft_generic with Norm = 'n' for the reverse transform. If ImageFFT1 and ImageFFT2 contain the same number of images, the corresponding images are phase-correlated pairwise. Otherwise, ImageFFT2 must contain only one single image. In this case, the phase correlation is performed for each image of ImageFFT1 with ImageFFT2 .
The filtering is always performed on the entire image, i.e., the domain of the image is ignored.
Fourier-transformed input image 1.
Fourier-transformed input image 2.
Number of elements: ImageFFT2 == ImageFFT1 || ImageFFT2 == 1
Phase correlation of the input images in the frequency domain.
* Compute the phase correlation of two images. get_image_size(Image1,Width,Height) rft_generic(Image1,ImageFFT1,'to_freq','none','complex',Width) rft_generic(Image2,ImageFFT2,'to_freq','none','complex',Width) phase_correlation_fft(ImageFFT1,ImageFFT2,PhaseCorrelationFFT) rft_generic(PhaseCorrelationFFT,PhaseCorrelation,'from_freq','n', \ 'real',Width) * Determine the translation between the two images. local_max_sub_pix (PhaseCorrelation, 'facet', 1, 0.02, Row, Column)
phase_correlation_fft returns 2 (H_MSG_TRUE) if all parameters are correct. If the input is empty the behavior can be set via set_system(::'no_object_result',<Result>:). If necessary, an exception is raised.
fft_generic, fft_image, rft_generic
fft_generic, fft_image_inv, rft_generic
C. D. Kuglin, D. C. Hines: “The Phase Correlation Image Alignment Method”; IEEE International Conference on Cybernetics and Society; pp. 163-165; 1975.