energy__ ( ImageGabor, ImageHilbert : Energy : : )

Calculate the energy of a two-channel image.

energy__ calculates the local contrast (Energy) of the two input images. The energy of the resulting image is then defined as berechnet den lokalen Kontrast 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__ is the Gabor-filtered image, transformed back into the spatial domain (see fft_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.


Parameters

ImageGabor (input_object)
image(-array) -> object : byte / real
1st channel of input image (usually: Gabor image).

ImageHilbert (input_object)
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.


Example
fft__(Image,&FFT);
gen_gabor(&Filter,1.4,0.4,1.0,1.5,512);
convol_gabor__(FFT,Filter,&Gabor,&Hilbert);
fft_inv__(Gabor,&GaborInv);
fft_inv__(Hilbert,&HilbertInv);
energy__(GaborInv,HilbertInv,&Energy);

Result

energy__ returns TRUE if all parameters are correct. If the input is empty the behaviour can be set via set_system(::'no_object_result',<Result>:). If necessary, an exception is raised.


Possible Predecessors

gen_gabor, convol_gabor__, fft_inv__



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