energy_gaborenergy_gaborEnergyGaborenergy_gaborEnergyGaborEnergyGabor (Operator)

Name

energy_gaborenergy_gaborEnergyGaborenergy_gaborEnergyGaborEnergyGabor — Calculate the energy of a two-channel image.

Signature

energy_gabor(ImageGabor, ImageHilbert : Energy : : )

energy_gaborenergy_gaborEnergyGaborenergy_gaborEnergyGaborEnergyGabor calculates the local contrast (EnergyEnergyEnergyEnergyEnergyenergy) 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_gaborconvol_gaborConvolGaborconvol_gaborConvolGaborConvolGabor). In this case, the first channel of the image passed to energy_gaborenergy_gaborEnergyGaborenergy_gaborEnergyGaborEnergyGabor is the Gabor-filtered image, transformed back into the spatial domain (see fft_image_invfft_image_invFftImageInvfft_image_invFftImageInvFftImageInv), 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.

Parallelization

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.

Parameters

ImageGaborImageGaborImageGaborImageGaborImageGaborimageGabor (input_object) (multichannel-)image(-array) → object (byte / real)

1st channel of input image (usually: Gabor image).

ImageHilbertImageHilbertImageHilbertImageHilbertImageHilbertimageHilbert (input_object) (multichannel-)image(-array) → object (byte / real)

2nd channel of input image (usually: Hilbert image).

EnergyEnergyEnergyEnergyEnergyenergy (output_object) image(-array) → object (real)

Image containing the local energy.

Example (C)

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);

Result

energy_gaborenergy_gaborEnergyGaborenergy_gaborEnergyGaborEnergyGabor 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>:)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

gen_gaborgen_gaborGenGaborgen_gaborGenGaborGenGabor, convol_gaborconvol_gaborConvolGaborconvol_gaborConvolGaborConvolGabor, fft_image_invfft_image_invFftImageInvfft_image_invFftImageInvFftImageInv

Module

Foundation

Operators