table of contents
| AMC-ANALYSE(1) | Auto Multiple Choice | AMC-ANALYSE(1) |
NAME¶
AMC-analyse - automatic data capture from scans for AMC multiple choice exams.SYNOPSIS¶
auto-multiple-choice
analyse --projet project-dir
[--seuil-coche threshold] [--tol-marque tol]
[--list-fichiers files-list.txt | scan-files...]
DESCRIPTION¶
The AMC-analyse.pl command performs automatic data capture from scans of completed answer sheets of an AMC multiple choice questionnaire. Before calling AMC-analyse.pl, AMC-prepare(1) should have been called to make working documents ( --mode s) and the layout should have been processed with AMC-meptex(1). --data data-dirgives the directory where data files are (see
for example AMC-meptex(1)). Defaults to project-dir/data.
--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.
--seuil-coche threshold
When deciding whether a box is checked or not,
AMC-analyse.pl compares the black ratio (number of black pixels over
total number of pixels) to threshold. If the black ratio is greater
then threshold, the box is declared to be checked. Standard values can
be 0.15 in the standard layout, or 0.5 for separate answer sheet layout (in
this last case, letters are drawn in the boxes, and the students are told to
fill the boxes entirely). The black ratio is written in the data capture
reports, so that this threshold value can be refined later without calling
AMC-analyse.pl again.
--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 acurate). 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 thie case, copy numbers are allocated to students so that their
answer sheets, with the same subject number, can be differenciated.
--pre-allocate copy_id
This option can be used in conjonction with
--multiple. The copy numbers used for the scans will start from
copy_id, in the same order than the scans given as arguments.
--debug file.log
gives a file to fill with debugging
information.
AUTHORS¶
Alexis Bienvenüe <paamc@passoire.fr>Main author
Jean Bérard
Translation from French
Georges Khaznadar
Translation from French
COPYRIGHT¶
Copyright © 2008-2012 Alexis Bienvenüe| 06/19/2012 | Auto Multiple Choice 1.1.1 |