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
--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) 2017-2021 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