HALCON Extension Package Programmer's Manual

54 CHAPTER 4. HALCON DATA TYPESNames¸ SynopsisÒÐÙ ÀÄÇƺÁÆÌ ´ÀÖÙÒÁÆÌÁÆÌÁÆÌ ´ÀÖÙÒÁÆÌÁÆÌÖиÒܸÛصÖиÒܸÛصFigure 4.6: Linear coordinates from ÀÖÐÖÓÒ.Ø ÓÒØÓÙÖ ÐÓÐ ØØÖ ÜÐ. See the Reference Manuals for details. Within HALCON,a specific attribute of a contour can be accessed using ÀÄÓÓÙÔÄÓÒØØØÖ, while a specificglobal attribute can be accessed using ÀÄÓÓÙÔÄÓÒØÐÓÐØØÖ. These routinesreturn the index of the desired attribute within ØØÖ× or ÐÓÐ of ÓÒØ, or the error codeÀ ÊÊ Ä Æ as result of the procedure call, if no attribute with the specified name is defined.The XLD data type ÀÔÓÐÝ , displayed in Figure 4.10, encodes subpixel accurate polygons.Basically it contains an array of control points. In many applications such polygons are derivedfrom contours. Thus, the data structure can also hold a reference to the underlying part of acontour specified by a HALCON data base key.4.4 Control Parameters (ÀÔÖ, ÀÔÖ)The HALCON data types ÀÔÖ and ÀÔÖ are used within the Extension Package Interface topass control parameters to supply procedures. Fig. 4.11 shows the corresponding definitions.ÀÔÖ encodes a single parameter value of one of the basic types ÒØÖ, ÖÐ or ×ØÖÒ, seesection 2.3. In addition to that, ÀÔÖ also encodes the corresponding type. Thus, it is possibleto combine different types within an array of ÀÔÖ values. The selector ØÝÔ can be set toÄÇÆ ÈÊ, ÄÇÌ ÈÊ or ËÌÊÁÆ ÈÊ.The Extension Package Interface procedures ÀØÈÖ, ÀØËÈÖ, ÀØÈÈÖ, ÀÈÙØÈÖ, andÀÈÙØÈÈÖ (section 5.5) are based on ÀÔÖ. They are used to access control parameters ofHALCON operators.HALCON Extension Package Interface / 2000-11-16