Exemple #1
0
def psf(array_shape=(256, 256), dx=1., lam_over_diam=2., defocus=0., astig1=0., astig2=0., coma1=0.,
        coma2=0., trefoil1=0., trefoil2=0., spher=0., circular_pupil=True, obscuration=0.,
        nstruts=0, strut_thick=0.05, strut_angle=0.*galsim.degrees, flux=1.):
    """Return NumPy array containing circular (default) or square pupil PSF with low-order 
    aberrations.

    The PSF is centred on the array[array_shape[0] / 2, array_shape[1] / 2] pixel by default, and
    uses surface brightness rather than flux units for pixel values, matching SBProfile.

    To ensure properly Nyquist sampled output any user should set lam_over_diam >= 2. * dx.

    Ouput NumPy array is C-contiguous.

    @param array_shape     the NumPy array shape desired for the output array.
    @param dx              grid spacing of PSF in real space units
    @param lam_over_diam   lambda / telescope diameter in the physical units adopted for dx 
                           (user responsible for consistency).
    @param defocus         defocus in units of incident light wavelength.
    @param astig1          astigmatism (like e2) in units of incident light wavelength.
    @param astig2          astigmatism (like e1) in units of incident light wavelength.
    @param coma1           coma along y in units of incident light wavelength.
    @param coma2           coma along x in units of incident light wavelength.
    @param trefoil1        trefoil (one of the arrows along y) in units of incident light
                           wavelength.
    @param trefoil2        trefoil (one of the arrows along x) in units of incident light
                           wavelength.
    @param spher           spherical aberration in units of incident light wavelength.
    @param circular_pupil  adopt a circular pupil?
    @param obscuration     linear dimension of central obscuration as fraction of pupil linear
                           dimension, [0., 1.).
    @param nstruts         Number of radial support struts to add to the central obscuration
                           [default `nstruts = 0`].
    @param strut_thick     Thickness of support struts as a fraction of pupil diameter
                           [default `strut_thick = 0.05`].
    @param strut_angle     Angle made between the vertical and the strut starting closest to it,
                           defined to be positive in the counter-clockwise direction; must be a
                           galsim.Angle instance [default `strut_angle = 0. * galsim.degrees`].
    @param flux            total flux of the profile [default flux=1.].
    """
    wf = wavefront(
        array_shape=array_shape, dx=dx, lam_over_diam=lam_over_diam, defocus=defocus, astig1=astig1,
        astig2=astig2, coma1=coma1, coma2=coma2, trefoil1=trefoil1, trefoil2=trefoil2, spher=spher,
        circular_pupil=circular_pupil, obscuration=obscuration, nstruts=nstruts,
        strut_thick=strut_thick, strut_angle=strut_angle)
    ftwf = np.fft.fft2(wf)  # I think this (and the below) is quicker than np.abs(ftwf)**2
    # The roll operation below restores the c_contiguous flag, so no need for a direct action
    im = utilities.roll2d((ftwf * ftwf.conj()).real, (array_shape[0] / 2, array_shape[1] / 2)) 
    return im * (flux / (im.sum() * dx**2))
Exemple #2
0
def psf(array_shape=(256, 256), dx=1., lam_over_diam=2., defocus=0., astig1=0., astig2=0., coma1=0.,
        coma2=0., spher=0., circular_pupil=True, obscuration=0., flux=1.):
    """Return NumPy array containing circular (default) or square pupil PSF with low-order 
    aberrations.

    The PSF is centred on the array[array_shape[0] / 2, array_shape[1] / 2] pixel by default, and
    uses surface brightness rather than flux units for pixel values, matching SBProfile.

    To ensure properly Nyquist sampled output any user should set lam_over_diam >= 2. * dx.

    Ouput NumPy array is C-contiguous.

    @param array_shape     the NumPy array shape desired for the output array.
    @param dx              grid spacing of PSF in real space units
    @param lam_over_diam   lambda / telescope diameter in the physical units adopted for dx 
                           (user responsible for consistency).
    @param defocus         defocus in units of incident light wavelength.
    @param astig1          first component of astigmatism (like e1) in units of incident light
                           wavelength.
    @param astig2          second component of astigmatism (like e2) in units of incident light
                           wavelength.
    @param coma1           coma along x in units of incident light wavelength.
    @param coma2           coma along y in units of incident light wavelength.
    @param spher           spherical aberration in units of incident light wavelength.
    @param circular_pupil  adopt a circular pupil?
    @param obscuration     linear dimension of central obscuration as fraction of pupil linear
                           dimension, [0., 1.)
    @param flux            total flux of the profile [default flux=1.]
    """
    wf = wavefront(
        array_shape=array_shape, dx=dx, lam_over_diam=lam_over_diam, defocus=defocus, astig1=astig1,
        astig2=astig2, coma1=coma1, coma2=coma2, spher=spher, circular_pupil=circular_pupil, 
        obscuration=obscuration)
    ftwf = np.fft.fft2(wf)  # I think this (and the below) is quicker than np.abs(ftwf)**2
    # The roll operation below restores the c_contiguous flag, so no need for a direct action
    im = utilities.roll2d((ftwf * ftwf.conj()).real, (array_shape[0] / 2, array_shape[1] / 2)) 
    return im * (flux / (im.sum() * dx**2))
Exemple #3
0
def psf(array_shape=(256, 256),
        dx=1.,
        lam_over_diam=2.,
        defocus=0.,
        astig1=0.,
        astig2=0.,
        coma1=0.,
        coma2=0.,
        trefoil1=0.,
        trefoil2=0.,
        spher=0.,
        circular_pupil=True,
        obscuration=0.,
        flux=1.):
    """Return NumPy array containing circular (default) or square pupil PSF with low-order 
    aberrations.

    The PSF is centred on the array[array_shape[0] / 2, array_shape[1] / 2] pixel by default, and
    uses surface brightness rather than flux units for pixel values, matching SBProfile.

    To ensure properly Nyquist sampled output any user should set lam_over_diam >= 2. * dx.

    Ouput NumPy array is C-contiguous.

    @param array_shape     the NumPy array shape desired for the output array.
    @param dx              grid spacing of PSF in real space units
    @param lam_over_diam   lambda / telescope diameter in the physical units adopted for dx 
                           (user responsible for consistency).
    @param defocus         defocus in units of incident light wavelength.
    @param astig1          astigmatism (like e2) in units of incident light wavelength.
    @param astig2          astigmatism (like e1) in units of incident light wavelength.
    @param coma1           coma along y in units of incident light wavelength.
    @param coma2           coma along x in units of incident light wavelength.
    @param trefoil1        trefoil (one of the arrows along y) in units of incident light
                           wavelength.
    @param trefoil2        trefoil (one of the arrows along x) in units of incident light
                           wavelength.
    @param spher           spherical aberration in units of incident light wavelength.
    @param circular_pupil  adopt a circular pupil?
    @param obscuration     linear dimension of central obscuration as fraction of pupil linear
                           dimension, [0., 1.)
    @param flux            total flux of the profile [default flux=1.]
    """
    wf = wavefront(array_shape=array_shape,
                   dx=dx,
                   lam_over_diam=lam_over_diam,
                   defocus=defocus,
                   astig1=astig1,
                   astig2=astig2,
                   coma1=coma1,
                   coma2=coma2,
                   trefoil1=trefoil1,
                   trefoil2=trefoil2,
                   spher=spher,
                   circular_pupil=circular_pupil,
                   obscuration=obscuration)
    ftwf = np.fft.fft2(
        wf)  # I think this (and the below) is quicker than np.abs(ftwf)**2
    # The roll operation below restores the c_contiguous flag, so no need for a direct action
    im = utilities.roll2d((ftwf * ftwf.conj()).real,
                          (array_shape[0] / 2, array_shape[1] / 2))
    return im * (flux / (im.sum() * dx**2))