energy_gabor — Calculate the energy of a two-channel image.
energy_gabor calculates the local contrast
(Energy) of the two input images. The energy of the
resulting image is then defined as
Often the calculation of the energy is preceded by the convolution
of an image with a Gabor filter and the Hilbert transform of the
Gabor filter (see convol_gabor). In this case, the
first channel of the image passed to energy_gabor is the
Gabor-filtered image, transformed back into the spatial domain (see
fft_image_inv), and the second channel the result of the
convolution with the Hilbert transform, also transformed back into
the spatial domain. The local energy is a measure for the local
contrast of structures (e.g., edges and lines) in the image.
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Automatically parallelized on tuple level.
- Automatically parallelized on channel level.
- Automatically parallelized on domain level.
ImageGabor (input_object) (multichannel-)image(-array) → object (byte / real)
1st channel of input image (usually: Gabor image).
ImageHilbert (input_object) (multichannel-)image(-array) → object (byte / real)
2nd channel of input image (usually: Hilbert image).
Energy (output_object) image(-array) → object (real)
Image containing the local energy.
energy_gabor returns 2 (H_MSG_TRUE) if all parameters are correct.
If the input is empty the behavior can be set via
necessary, an exception is raised.