Level 2 Help for MARSFAKEDISP

INP

Two files containing the input stereo pair images.  The pixel data from these
images are not used; only the pointing and camera models are.

A single file list file may also be specified (a la marsmos, etc.), but the
file list must have only two entries.

Note that there's no actual requirement that the first input be left or the
second right.  The two images can be given in any order.  The first image,
though, is the "master" image; the disparity map matches first image's
pixels.  Convention places left first, however.


OUT

Output files containing the fake disparities.

If two filenames are given, two separate 1-band files will be created,
one each for line and sample disparity.  If only one filename is given,
a single 2-band file will be created, with bands in (line,sample) order.

The output files are in REAL (float) format.


NAVTABLE

Corrected navigation filename.
If marsnav was run on the input images it created a table of corrected
pointing parameters. If you refer to this table using NAVTABLE it
will override the pointing parameters (e.g. azimuth and elevation) in the
picture labels, giving different (and presumably better) output coordinates.


PYRLEVEL

Specifies the "pyramid level" at which to generate the output.  0 represents
full-size, 1 is half scale, 2 is quarter scale, etc.  This value must also
be provided to marscor3 in the disp_pyramid parameter.  A value of 4 seems
to be appropriate in most cases with this program.


AVERAGE

Specifes whether or not to compute an average surface model.  If given,
the surface is the average of the GROUND/NORMAL parameters interpreted using
SITE frame, and the same parameters interpreted using the frame specified by
COORD (usually -ROVER).  If not given, the surface is the one made by
interpreting the parameters the frame specified by COORD.

See the main help for more discussion.


CONFIG_PATH

A colon-separated list of directories in which to look for configuration
and calibration files.  Environment variables are allowed in the list
(and may themselves contain colon-separated lists).  The directories are
searched in order for each config/cal file when it is loaded.  This allows
multiple projectes to be supported simultaneously, and allows the user to
override any given config/cal file.  Note that the directory structure below
the directories specified in this path must match what the project expects.
For example, Mars 98 expects flat fields to be in a subdirectory named
"flat_fields" while Mars Pathfinder expects them to be directly in the
directory specified by the path (i.e. no intermediate subdirectories).


MATCH_METHOD

Specifies a method for pointing corrections.

Loose method matches with pointing parameters of the image.
Tight method matches with unique id of the image.


MATCH_TOL

Tolerance value for matching pointing parameters in the pointing corrections file.
Used if MATCH_METHOD=LOOSE
Default value is pretty arbitrary, though seems to work well so far....


POINT_METHOD

Specifies a mission-specific pointing method to use.  Normally this
parameter is not used, in which case the "default" pointing methods
are used.  Some missions may have special, or alternate, pointing
methods available, which are indicated by this string (for example,
backlash models, using arm joint angles instead of x/y/z/az/el, etc).
A substring search is used, so multiple methods (where that makes sense)
can be specified by separating the keywords with commas.

Note that nav files created using one pointing method will most likely
not be compatible with a mosaic created using a different pointing method.

The methods available vary per mission, but some methods available at
the time of this writing are:

BACKLASH : Mars 98 SSI only.  Selects a backlash pointing model,
which adjusts the telemetered azimuth and elevation values based on
knowledge of the camera's mechanical backlash and the direction the
motor was travelling when the image was taken.


NORMAL

The local mars surface normal vector coordinate system specified by SURF_COORD 
parameter (defaults to surface fixed).
For most pan/tilt cameras, if the lander is not tilted this vector
would be: normal=(0,0,-1).  ie: x_component=0, y_component=0, z_component=-1.
This need not be a unit vector.  This vector is used to define the
surface plane to which image points are projected in order to minimize
parallax.
For SPHERE1/2 surface models, normal's first parameter is used to
denote sphere's radius.  Thus to describe sphere of radius R, user
would specify normal=(R, 0, 0).


GROUND

Any point on the surface, in coordinate system specified by SURF_COORD parameter
(defaults to surface fixed).  This defines where the tilted plane is in space.  
Although any point may be used, normally the point just "under" the origin is selected.
Defaults:
Mars Pathfinder:  (0.0, 0.0, 0.0)       (lander zero point is on the ground)
Mars 98 Lander:   (0.0, 0.0, 1.64)      (lander zero point is on top of deck)
MER           :   (0.0, 0.0, 0.294)
For MER images taken on top of the lander, the ground is roughly at (0.0, 0.0, 0.7)
For SPHERE1/2 surface models, GROUND parameter is used to denote sphere's
center.  
    


SURF_COORD

The coordinate system that surface parameters like GROUND and NORMAL are defined in.
For valid values refer to COORD parameter description.  The interpretation of the 
values is dependent on the mission. Defaults to surface fixed coordinate system.
Note that no validation is done for input strings because COORD is using the same
values.  So user needs to be extra careful in specifying SURF_COORD value.  For 
example COORD=local would be correctly interpreted to mean LOCAL_LEVEL because of
validation process.  On the other hand specifying SURF_COORD=local would lead
to underlying code treating the input value as invalid and reverting to default
which is FIXED frame.  So the values for SURF_COORD should be spelled exactly as
found in the list of valid values for COORD parameter.


SURFACE

The type of mars surface to use. The surface is used to intercept view rays
emanating from the cameras in order to model out parallax between the
stereo cameras. The options are surface=INFINITY which means no surface
is used, surface=PLANE (the default case). If surface = PLANE then the plane
is defined by the NORMAL and GROUND parameters.  For the cases when PLANE
doesn't match local topography sufficiently well, there are two sphere surface
models: surface=SPHERE1 and surface=SPHERE2.  SPHERE1 is useful to model
convex surfaces like hills, it returns closest(first) ray-surface intersection
point.  SPHERE2 is useful to model concave surfaces, like crater when the
camera point is outside looking in, it returns farthest(second) ray-surface
intersection point.  For the case when camera is inside the sphere surface,
like rover sitting in the crater, there is only a single intersection point
and SPHERE1 and SPHERE2 behave exactly the same.


RSF

Rover State File.  This is a list of filenames to load containing
Rover State information.  These files contain position and orientation
information for a rover (or other mobile spacecraft) at various sites.
They are in XML format.  See the "Rover Motion Counter (RMC) Master File SIS"
for details on these files.

Rover State Files have a priority order.  The files listed first have
the highest priority.

Environment variables may be used in the list.

For MER, if a directory is specified, then that directory is searched for
RMC Master files and any found are loaded.  The directory structure and
filename convention is covered in the RMC SIS.  The directory specified
is the one containing "master", so if <dir> is the name specified in the
RSF parameter, the following files will be searched for:

<dir>/master/_Master.svf
<dir>/master/_Site__Master.rvf

The name of each file loaded is printed to the stdout log for reference.


DEBUG_RSF

If enabled, this causes the internal database of RMC locations to be
printed out to the stdout log.  This is after the RSF files have been
loaded and the coordinate systems read from the input label(s).


COORD

Specifies the coordinate system to use to interpret the surface model
parameters (GROUND and NORMAL).  See the AVERAGE parameter and the main
help for more details.

The interpretation of the values is dependent on the mission.  Some
representative missions are listed here:

Fixed - The Fixed frame (default).  This is the ultimate reference frame
    (see also FIXED_SITE for rover missions).
Instrument - The "natural" frame for the instrument (of the first input
    image).  MPF: Lander or Rover; M98: MVACS; MER: Rover.
Site - A major Site frame.  For rover missions, COORD_INDEX specifies which
    Site frame to use.  Non-rover missions treat this as Fixed.
Rover - An instance of the Rover frame.  For rover missions, COORD_INDEX
    specifies which instance of the rover frame to use.  Non-rover mission
    use the spacecraft frame (e.g. Lander for M98).
Local_Level - An instance of a Local Level frame.  This is typically
    coincident with the Rover frame (in XYZ) but oriented toward North
    like the Site and Fixed frames.  For MER, this is an instance of a
    Drive index move.


COORD_INDEX

The index specifies which instance of a coordinate system to use.  It is
currently applicable only to rover-based missions, but could have other
uses.  The index is equivalent to the Rover Motion Counter (RMC) for MER
and FIDO.

For MER/FIDO, there are many Site frames.  Each is numbered with a single
index.  For Site Frames, coord_index specifies which to use.  Likewise,
there are many Local_Level and Rover frames, corresponding to values of
the RMC.  The multiple instances of this frame are selected by COORD_INDEX.

Generally COORD_INDEX defaults sensibly so you don't usually need to
specify it.  It will default to the instance used by the first input.


FIXED_SITE

Specifies which major Site is the "Fixed" Site for this run.

Historically, MPF and M98 had a single "Surface Fixed" frame which never
moved, and which all other coordinate system frames were referenced to.
With the advent of long-range rovers (such as MER and FIDO), that became
insufficient.  The rover traverses far enough that errors in knowledge of
coordinate system offset and orientation become unacceptable.

For this reason, a system of major Sites was introduced.  Periodically
during the mission, a Site frame is declared.  This then becomes the
reference frame for all activities until the next Site is declared.
References are kept local, and errors don't propogate across Sites.

However, if images from more than one Site are combined together, the
Site's must be placed relative to each other.  Therefore a single reference
frame is still needed to combine different sites.

The FIXED_SITE parameter controls which of the major Site frames is
the reference ("fixed") site for this program run.  This fixed frame
can vary in different program runs, but is constant throughout one
execution.

If not specified, FIXED_SITE defaults to the minimum Site number (i.e.
lowest numbered, or earliest chronologically) used in all input images.
Normally this default is sufficient; rarely must FIXED_SITE be specified.

One or more Rover State Files must usually be specified in order to combine
image from more than one Site.  These describe the relationship between
sites.  See the RSF parameter.


SOLUTION_ID

Specifies which solution ID to use when specifying the coordinate system.

There are potentially many different definitions for the same coordinate
system.  These are identified via a unique Solution ID.  If this parameter
is given, only the specified solution's definition is searched for.  Without
it, the "best" available solution is chosen.

It is extremely rare that this parameter should be needed.  The default
will be sufficient in almost every case.

Note that the current MER implementation requires that a value for COORD_INDEX
also be provided, in order for this parameter to take effect.