ymira - reconstruct an image from optical interferometric data
ymira [OPTION]... INPUT... OUTPUT
MiRA is a software to reconstruct images from optical
interferometric data. The algorithm performs a regularized fit of the data
with additional constraints such as normalization and lower and/or upper
bounds.
INPUT... are the input OI-FITS data file(s) and
OUTPUT is the result saved into a FITS file.
Options are introduced by a word prefixed with one or two hyphens
(at your convenience). In case the first input file starts with an hyphen, a
double hyphen can be used to indicate the end of the options.
Some options have units. Angles must be suffixed with mas,
milliarcsec, milliarcsecond, milliarcseconds,
deg, degree, degrees, rad, radian or
radians. Lengths must be suffixed with m, meter,
meters, mm, millimeter, millimeters,
µm, micron, microns, micrometer,
micrometers, nm, nanometer or nanometers.
Some options may take several values which are separated by
commas.
The following options can be used to select which data to
consider. If no spectral range is given (either with options -effwave
and -effband or with options -wavemin and -wavemax), an
image is reconstructed from all available wavelengths.
- -target=name
- Specify the name of the astrophysical object. This option is used to
select a specific target from the input file(s). If there is a single
target which is identical in all input files, this option may be
omitted.
- -effwave=length
- Specify the effective wavelength; for example, -effwave=1.6micron.
This is the central wavelength of the spectral range to consider.
- -effband=length
- Specify the effective bandwidth; for example, -effband=200nm. This
the full width of the spectral range to consider.
- -wavemin=length
- Specify the minimum wavelength; for example, -wavemin=1.5µm.
This the lower bound of the spectral range to consider.
- -wavemax=length
- Specify the maximum wavelength; for example, -wavemin=1.7µm.
This the upper bound of the spectral range to consider.
At least the pixel size (with option -pixelsize) and the
image dimensions (with options -fov or -dim) must be
specified.
- -pixelsize=angle
- Specify the angular size of pixels. For example,
-pixelsize=0.1mas.
- -fov=angle
- Specify the angular size of the field of view. For example,
-fov=20mas.
- -dim=number
- Specify the number of pixels per side of the image. For example,
-dim=200.
- -normalization=value
- Specify the sum of pixels. A recommended setting is:
-normalization=1.
- -min=lower
- Specify the lower bound for the pixel values. A recommended setting
is:-min=0.
- -max=upper
- Specify the upper bound for the pixel values.
- -xform=name
- Specify the method to compute the nonequispaced Fourier transform.
Argument name can be nfft, exact or fft (the
latter value is however not recommended).
- -regul=name
- Specify the name of the regularization method.
- -mu=value(s)
- Specify the global regularization weight(s) µ. If a single value is
given, it will be used for all reconstructions. If two values are given
(separated by comas), a different value of µ will be used for each
reconstructions with the values of µ spaced at equal ratios from
start to stop (that is, equally spaced
logarithmically).
- -tau=value
- Specify the edge preserving threshold. value must be strictly
positive.
- -eta=value(s)
- Specify the gradient scales along dimensions.
- -gamma=angle
- Specify the a priori full half width at half maximum (FWHM). For example:
-gamma=15mas.
- -quiet
- Suppress most messages.
- -verb=count
- Set the verbose level. Information will be printed every count
iteration. Also see option -view.
- -view=bits
- Bitwise value to specify which graphics to show each time some information
is printed. The least significant bits of bits indicate which
sub-panel to display. Use -view=0 to suppress all graphics and
-view=-1 to show all graphics. The default is to not display
anything. If some graphics are shown, the graphic window has to be closed
at the end of the reconstruction to effectively quit the program.
- -mem=number
- Specify the number of previous steps to memorize in VMLMB.
- -ftol=real
- Specify the function tolerance for the global convergence.
- -gtol=real
- Specify the gradient tolerance for the global convergence.
- -maxiter=number
- Specify the maximum number of iterations for all reconstructions.
- -maxeval=number
- Specify the maximum number of evaluations of the objective function for
all reconstructions.
- -sftol=real
- Specify the function tolerance for the line search.
- -sgtol=real
- Specify the gradient tolerance for the line search.
- -sxtol=real
- Specify the step tolerance for the line search.
- -overwrite
- Overwrite output file if it exists.
- -bitpix=number
- Specify the bits per pixel for the output FITS file. Default is
-32, that is 32-bit floating point values.
- -save_initial
- Save initial image as a secondary HDU in the output file.
Éric Thiébaut
<https://github.com/emmt/MiRA>
Thiébaut, É.: MiRA: an effective imaging
algorithm for optical interferometry, in SPIE Proc. Astronomical
Telescopes and Instrumentation 7013, 70131I-1-70131I-12 (2008)
<http://dx.doi.org/10.1117/12.788822>
Thiébaut, É. & Giovannelli, J.-F.: Image
Reconstruction in Optical Interferometry, in IEEE Signal
Processing Magazine 27, pp. 97-109 (2010)
<http://dx.doi.org/10.1109/MSP.2009.934870>