Compute the fast Fourier transform of an image.
::fft_image calculates the Fourier transform of the input image (Image), i.e., it transforms the image into the frequency domain. The algorithm used is the fast Fourier transform. This corresponds to the call
fft_generic(Image,ImageFFT,'to_freq',1,'n','dc_center':)
The result image is of type 'complex'.
The filtering is always done on the entire image, i.e., the region of the image is ignored. The images must be quadratic and the width and height must be a power of 2.
|
Image (input_object) |
image(-array) -> Hobject: HImage(Array) ( byte / real ) |
| Input image. | |
|
ImageFFT (output_object) |
image(-array) -> Hobject * : HImage(Array) ( complex ) |
| Fourier-transformed image. | |
fft_image(Image,&FFT); gen_gabor(&Filter,1.4,0.4,1.0,1.5,512); convol_gabor(FFT,Filter,&Gabor,&Hilbert); fft_image_inv(Gabor,&GaborInv); fft_image_inv(Hilbert,&HilbertInv); energy_gabor(GaborInv,HilbertInv,&Energy);
::fft_image returns H_MSG_TRUE if the input image is of correct type and its width and height are a power of 2. If the input is empty the behaviour can be set via ::set_system('no_object_result',<Result>). If necessary, an exception handling is raised.
::convol_fft, ::convol_gabor, ::convert_image_type, ::power_byte, ::power_real, ::power_ln, ::phase_deg, ::phase_rad
Image filters
