endstop1

Compute the single 2D EndStop Wavelet in frequency plane

Syntax

[out] = endstop1(kx,ky,k_0,sigma)

Description

This function computes the single 2D EndStop wavelet in frequency plane. This wavelet is by the derivation according to y of the Morlet wavelet of main frequency vector (k0,0).

  PSIHAT (kx,ky) = 
     (i*ky) * exp( - sigma^2 * ( (kx-k_0).^2 + ky.^2 ) / 2)

where PSIHAT is the Fourier transform of PSI.

This wavelet depends of two parameters: k_0 and sigma. This function is used by the cwt2d routine which computes continuous wavelet transform in 2D.

Input Data

kx,ky

[REAL MATRICES]: The frequency plane. Use meshgrid to create it.

sigma

[REAL SCALAR]: The wavelet spread factor.

epsilon

[REAL SCALAR]: The wavelet anisotropy factor.

Output Data

out

[REAL MATRIX]: The wavelet in frequency plane.

Example(s)

>> step = 2*pi/128;
>> [kx,ky] = meshgrid( -pi : step : (pi-step) );
>> wav = endstop1(kx,ky,6,1,1);
>> yashow(wav);

References

[1] Sushil Kumar BHATTACHARJEE, "A Computational Approach to Image Retrieval", PhD Thesis, EPFL, Lausanne, 1999.

See Also

cwt2d cwt2d_yashow endstop2 meshgrid samcwt2d samcwt2d_yashow sarcwt2d

Location

continuous/2d/wave_defs/endstop1.m