The auto-multiple-choice analyse command performs automatic
data capture from scans of completed answer sheets of an AMC multiple choice
questionnaire. Before calling auto-multiple-choice analyse,
auto-multiple-choice-prepare(1) should have been called to make
working documents (--mode s) and the layout should have been
processed with auto-multiple-choice-meptex(1).
--data data-dir
--cr project-cr-dir
gives a directory where to create image reports of the
data capture (zooms on the boxes in a zooms sub-directory, name filed
extraction as a name-*.jpg file, and layout report as a page-*.jpg
file).
--projet project-dir
When using this option, if --cr is not used,
project-cr-dir will be set to project-dir/cr.
Giving the names of the scan files to process can be done in two
ways:
•these names can be given as arguments,
•these names can be written to a plain file (one
filename per line), using the --list-fichiers
files-list.txt to give the name of this file.
Some parameters for data capture may be set using the following
options:
--prop proportion
sets the proportion of each box that will be measured to
decide if the box is ticked or not. Default value is 0.8.
--bw-threshold threshold
This parameter is used when converting the grayscale scan
file to black and white. To get more black pixels, use a greater value. To get
more white pixels, use a smaller value. The threshold must be between 0 and 1.
The default value is 0.6.
--ignore-red
With this option, only red channel will be used from
color scans. This way, all that is written in red will be ignored in the scan.
This can be useful when the boxes are printed in red.
--tol-marque tol
defines the tolerance when detecting the four marks in
the scans corners. These marks are detected looking for black connected
components which dimensions are closed to the target dimension
target (exact dimensions of the marks if printing/scanning process
where perfectly accurate). If tol is a real number, accepted dimensions
are those between (1-tol)*target and
(1+tol)*target. If tol is
"tinf,tsup" (where tinf and tsup are
real numbers), accepted dimensions are those between
(1-tinf)*target and (1+tsup)*target. A standard
value is 0.2.
--multiple
This option is to be used when the scans are photocopies
from some subjects (different students can have the same subject). In this
case, copy numbers are allocated to students so that their answer
sheets, with the same subject number, can be differentiated.
--pre-allocate copy_id
This option can be used in conjunction with
--multiple. The copy numbers used for the scans will start from
copy_id, in the same order than the scans given as arguments.
--try-three | --no-try-three
Use one of these options to tell if you allow processing
of scans where only three corner marks are present.
--debug file.log
gives a file to fill with debugging information.