HALCON Extension Package Programmer's Manual

Chapter 1IntroductionHALCON can be extended by up to 99 additional operator packages. During the initializationof the system all packages indicated by the environment variable ÀÄÇÆÌÆËÁÇÆË areautomatically loaded. A package typically contains libraries with the new operators, their prototypes,the operator information needed by HDevelop, and the HTML online documentation.For the programming of such a package the HALCON Extension Package Interface is used,e.g., to manipulate parameters of HALCON operators and to read or write iconic data (images,regions, XLDs 1 ) from the HALCON data base.Furthermore, the operators provided by HALCON itself are also based on the functionality ofthe Extension Package Interface. Thus, the Extension Package Interface is both the interface betweenapplication programs and the operator layer of the the HALCON system and the interfacebetween the operator layer and the object data base.A reason why to extend the capabilities of HALCON by using the Extension Package Interfacemight be one of the following:¯ Extension of the pool of image processing operators,¯ Integration of special image processing hardware,¯ Integration of a special graphics software package.Once the user has extended HALCON by a package containing his/her own operators, they canbe used within all supported host-languages, and the interactive tool ÀÚÐÓÔ.This chapter gives a short introduction to HALCON packages and operators, includingan example describing the integration of a simple operator. The followingchapters present detailed information that will allow you to write your own packages.As a common example, a package called ÐÓÒÙ×Ö will be used (see±ÀÄÇÆÊÇÇ̱ÒÜÑÔÐ×ÒÜØÒ×ÓÒ ÔÒÐÓÒÙ×Ö on the HALCON CD).Except of UNIX specific sections in this manual file paths and environment variables are printedin the Windows NT/ 2000 convention, e.g.,±ÀÄÇÆÊÇÇ̱ÒÜÑÔÐ×ÒÜØÒ×ÓÒ ÔÒÐÓÒÙ×Ö1 eXtended Line Description; i.e. subpixel contours and polygons.1