mrcal-cull-corners - Filters a corners.vnl on stdin to cut out some points


  $ < corners.vnl mrcal-cull-corners --cull-left-of 1000 > corners.culled.vnl


This tool reads a set of corner detections on stdin, throws some of them out, and writes the result to stdout. This is useful for testing and evaluating the performance of the mrcal calibration tools.

The specific operation of this tool is defined on which --cull-... option is given. Exactly one is required:

  --cull-left-of X: throw away all corner observations to the left of the given
    X coordinate

  --cull-rad-off-center D: throw away all corner observations further than D
    away from the imager center. --imagersize must be given also so that we know
    where the imager center is

  --cull-random-observations-ratio R: throws away a ratio R object observations
    at random. To throw out half of all object observations, pass R = 0.5.
    --object-width-n and --object-height-n are then required to make the parsing

--cull-left-of X and --cull-rad-off-center throw out individual points. This is done by keeping the point in the output data strem, but setting its decimation level to '-'. The downstream tools then know to ignore those points

--cull-random-observations-ratio throws out whole object observations, not just individual points. These removed observations do not appear in the output data stream at all

This tool exists primarily for testing, and probably you don't want to use it. The filtering is crude, and the tool might report chessboard observations with very few remaining points. You PROBABLY want to post-process the output to keep only observations with enough points. For instance:

  mrcal-cull-corners ... > culled-raw.vnl

  vnl-join --vnl-sort - -j filename culled-raw.vnl \
     <(< culled-raw.vnl vnl-filter -p filename --has level |
                        vnl-uniq -c |
                        vnl-filter 'count > 20' -p filename ) \
  > culled.vnl



  -h, --help            show this help message and exit
  --object-width-n OBJECT_WIDTH_N
                        How many points the calibration board has per
                        horizontal side. This is required if --cull-random-
  --object-height-n OBJECT_HEIGHT_N
                        How many points the calibration board has per vertical
                        side. If omitted, I assume a square object and use the
                        same value as --object-width-n
                        Size of the imager. This is required if --cull-rad-
  --cull-left-of CULL_LEFT_OF
                        Throw out all observations with x < the given value.
                        Exclusive with the other --cull-... options
  --cull-rad-off-center CULL_RAD_OFF_CENTER
                        Throw out all observations with dist_from_center > the
                        given value. Exclusive with the other --cull-...
  --cull-random-observations-ratio CULL_RANDOM_OBSERVATIONS_RATIO
                        Throw out a random number of board observations. The
                        ratio of observations is given as the argument. 1.0 =
                        throw out ALL the observations; 0.0 = throw out NONE
                        of the observations. Exclusive with the other
                        --cull-... options



Dima Kogan, <>


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