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-dir
gives 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:
o these names can be given as arguments,
o 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 Bienvenue <paamc@passoire.fr>
Main author
Jean Berard
Translation from French
Georges Khaznadar
Translation from French
COPYRIGHT
Copyright (C) 2008-2012 Alexis Bienvenue
This document can be used according to the terms of the GNU General Public License, version 2 or later.
Auto Multiple Choice 1.1.1 06/19/2012 AMC-ANALYSE(1)