Return the power spectrum of a complex image.

power_ln computes the power spectrum from the real and imaginary parts of a Fourier-transformed image (see fft_image), i.e., the modulus of the frequencies. Additionally, the natural logarithm is applied to the result. The result image is of type 'real'. The following formula is used:

  ln(sqrt(real part**2 + imaginary part**2)) .

read_image(&Image,"monkey");
disp_image(Image,WindowHandle);
fft_image(Image,&FFT);
power_ln(FFT,&Power);
disp_image(Power,WindowHandle);

power_ln returns 2 (H_MSG_TRUE) if the image is of correct type. If the input is empty the behaviour can be set via set_system(::'no_object_result',<Result>:). If necessary, an exception handling is raised.

power_ln is reentrant and automatically parallelized (on tuple level, domain level).

fft_image, fft_generic, convol_fft, convol_gabor

disp_image, convert_image_type, scale_image

abs_image, convert_image_type, power_real, power_byte

fft_image, fft_generic

Image filters