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
energy = channel1 ^2 + channel2 ^2 .
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.
1st channel of input image (usually: Gabor image).
2nd channel of input image (usually: Hilbert image).
Image containing the local energy.
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);
energy_gabor 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.
gen_gabor, convol_gabor, fft_image_inv