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)) .
|
Image (input_object) |
image(-array) -> Hobject: HImage(Array) ( complex ) |
| Input image in frequency domain. | |
|
ImageResult (output_object) |
image(-array) -> Hobject * : HImage(Array) ( real ) |
| Power spectrum of the input image. | |
read_image(&Image,"affe"); disp_image(Image,WindowHandle); fft_image(Image,&FFT); power_real(FFT,&Power); disp_image(Power,WindowHandle);
::power_ln returns 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.
::fft_image, ::fft_generic, ::convol_fft, ::convol_gabor
::disp_image, ::convert_image_type, ::scale_image
::abs_image, ::convert_image_type, ::power_real, ::power_byte
Image filters
