Ubuntu Manpage: mrcal-show-residuals - Visualize calibration residuals in an imager

NAME

       mrcal-show-residuals - Visualize calibration residuals in an imager

SYNOPSIS

         $ mrcal-show-residuals --vectorfield left.cameramodel

         ... a plot pops up showing the vector field of residuals for this camera

DESCRIPTION

This tool supports several different modes, selected by the commandline arguments. Exactly
one of these mode options must be given:

--vectorfield Visualize the optimized residuals as a vector field. Each
vector runs from the observed chessboard corner to its
prediction at the optimal solution.

--magnitudes Visualize the optimized residual magnitudes as color-coded
points. Similar to --vectorfield, but instead of a vector, each
residual is plotted as a colored circle, coded by the MAGNITUDE
of the error. This is usually more legible.

--directions Visualize the optimized residual directions as color-coded
points. Similar to --vectorfield, but instead of a vector, each
residual is plotted as a colored circle, coded by the DIRECTION
of the error. This is very useful in detecting biases caused by
a poorly-fitting lens model: these show up as clusters of
similar color, instead of a random distribution.

--regional Visualize the optimized residuals, broken up by region. The imager
of a camera is subdivided into bins. The residual statistics are
then computed for each bin separately. We can then clearly see
areas of insufficient data (observation counts will be low). And
we can clearly see lens-model-induced biases (non-zero mean) and
we can see heteroscedasticity (uneven standard deviation). The
mrcal-calibrate-cameras tool uses these metrics to construct a
valid-intrinsics region for the models it computes. This serves as
a quick/dirty method of modeling projection reliability, which can
be used even if projection uncertainty cannot be computed.

--histogram Visualize the distribution of the optimized residuals. We display
a histogram of residuals and overlay it with an idealized
gaussian distribution.

OPTIONS

   POSITIONAL ARGUMENTS
         model                 Camera model that contains the optimization_inputs
                               that describe the solve. The displayed observations
                               may come from ANY of the cameras in the solve, not
                               necessarily the one given by this model

   OPTIONAL ARGUMENTS
         -h, --help            show this help message and exit
         --vectorfield         Visualize the optimized residuals as a vector field
         --magnitudes          Visualize the optimized residual magnitudes as color-
                               coded points
         --directions          Visualize the optimized residual directions as color-
                               coded points
         --regional            Visualize the optimized residuals, broken up by region
         --histogram           Visualize the distribution of the optimized residuals
         --histogram-this-camera
                               If given, we show the histogram for residuals for THIS
                               camera only. Otherwise (by default) we display the
                               residuals for all the cameras in this solve. Implies
                               --histogram
         --valid-intrinsics-region
                               If given, I overlay the valid-intrinsics regions onto
                               the plot. Applies to all the modes except --histogram
         --gridn GRIDN GRIDN   How densely we should bin the imager. By default we
                               use a 20x14 grid of bins. Applies only if --regional
         --binwidth BINWIDTH   The width of binds used for the histogram. Defaults to
                               0.02 pixels. Applies only if --histogram
         --vectorscale VECTORSCALE
                               Scale all the vectors by this factor. Useful to
                               improve legibility if the vectors are too small to
                               see. Applies only if --vectorfield
         --cbmax CBMAX         Maximum range of the colorbar used in --vectorfield,
                               --magnitudes. If omitted, we autoscale
         --title TITLE         Title string for the plot. Overrides the default
                               title. Exclusive with --extratitle
         --extratitle EXTRATITLE
                               Additional string for the plot to append to the
                               default title. Exclusive with --title
         --hardcopy HARDCOPY   Write the output to disk, instead of making an
                               interactive plot. If --regional, then several plots
                               are made, and the --hardcopy argument is a base name:
                               "--hardcopy /a/b/c/d.pdf" will produce plots in
                               "/a/b/c/d.XXX.pdf" where XXX is the type of plot being
                               made
         --terminal TERMINAL   gnuplotlib terminal. The default is good almost
                               always, so most people don't need this option
         --set SET             Extra 'set' directives to gnuplotlib. Can be given
                               multiple times
         --unset UNSET         Extra 'unset' directives to gnuplotlib. Can be given
                               multiple times

REPOSITORY

       <https://www.github.com/dkogan/mrcal>

AUTHOR

       Dima Kogan, "<dima@secretsauce.net>"

LICENSE AND COPYRIGHT

       Copyright (c) 2017-2023 California Institute of Technology ("Caltech"). U.S.  Government
       sponsorship acknowledged. All rights reserved.

       Licensed under the Apache License, Version 2.0 (the "License"); You may obtain a copy of
       the License at

           http://www.apache.org/licenses/LICENSE-2.0