MVTec HALCON 5.2: Virtual framegrabber interface

HALCON 5.2 virtual framegrabber interface

This document provides some information about the HALCON virtual framegrabber interface VirtualFG. Registered customers can download the latest revision of this interface from the MVTec WWW server.

Revision: 1.29

Introduction

The HALCON virtual framegrabber interface allows you to load images and image sequences from files by using the framegrabber operators open_framegrabber(), grab_image(), and close_framegrabber(). Thus, you are able to test and debug your framegrabber application without having installed a real framegrabber board in your computer. All you have to do is to choose "VirtualFG" in the parameter Name of open_framegrabber() and to give the proper file name of the image(s) to be loaded in the parameter Generic. The Generic parameter can be either the file name of a

Single image: In this case every subsequent call of the operator grab_image() will load this image file. Note that the image name can either be given absolutely (e.g., "C:\MyImages\MyPicture") or relatively to your environment setting %HALCONIMAGES% (e.g., "MyPicture").

Sequence file: A sequence file is a file which contains in each line the name of a single image file. In this case the first call of the operator grab_image() will load the first image file, the second call will load the second one etc. After the last entry in the sequence file has been reached grab_image() will start from the first image file again (looping). Both the name of the sequence file as the image file names within the sequence file can either be given absolutely (e.g., "C:\MyImages\MySequence") or relatively to your environment setting %HALCONIMAGES%. Usually, the sequence file has the extension ".seq". All images within a sequence must have the same image size and the same bitdepth (8 or 24 bits).

An example for using the HALCON virtual framegrabber interface can be found in the examples/hdevelop/Applications/FA directory, e.g., "pattern.dev". An example for a sequence file can be found in %HALCONROOT%\images\pendulum\. Attention: You have to specify the image file names without extensions (e.g., "fabrik" instead of "fabrik.tif").

System Requirements

HALCON virtual framegrabber interface VirtualFG.dll (or VirtualFG.so for most UNIX systems, respectively). Depending on your system architecture, VirtualFG should reside either in bin\i486-nt4 (Windows NT) or in lib/$ARCHITECTURE (UNIX systems) within the HALCON base directory %HALCONROOT% you have chosen during the installation of HALCON.

Description

Parameters for open_framegrabber():

Name 'VirtualFG' The name of the HALCON framegrabber interface.

FGWidth --- Ignored.

FGHeight --- Ignored.

Width --- Ignored.

Height --- Ignored.

StartRow --- Ignored.

StartColumn --- Ignored.

Field --- Ignored.

Bits --- Ignored.

ColorSpace --- Ignored.

Gain --- Ignored.

ExternalTrigger --- Ignored.

Generic 'filename' The generic parameter is used to specify the file name of either a single image file or a sequence file containing the file names of a whole image sequence (see introduction above). Default: 'fabrik'.

Device --- Ignored.

Port --- Ignored.

LineIn --- Ignored.

Parameters for set_framegrabber_param(): Not supported.

Parameters for get_framegrabber_param():

'revision' revision Revision of the HALCON virtual framegrabber interface VirtualFG.

Release Notes

Revision 1.29 (Dec 29, 2001):

Bugfix in grabbing from sequence files.

Revision 1.28 (Jun 22, 2001):

Grabbing of images with file type '.ima'.
Grab calls ignore load failures of images in sequence files.

Revision 1.27 (March 29, 1999):

HALCON 5.2 version of the interface (included in the HALCON 5.2 CD).
Automatic restart from the beginning in a sequence file when end is reached (looping).

Revision 1.26 (March 28, 1999):

New parameter 'revision'.

Last modified: Mon Dec 31 12:52:04 CET 2001