Patent EP-0206214-B1 (EP)
IPC: G06V10/46
Filed: 1986-06-16
Granted: 1989-11-15
Abstract: 1. Method for a uniform symbolic description of document patterns in the form of data structures in an automated apparatus, in which method the document patterns can be composed of the components "text", "graphics" and/or "image", for the purpose of separating the document pattern into these components and for further processing these components in evaluating modules for special cases of application, in which connection descriptors which represent interpolation points along edges in a relevant document pattern are extracted line by line from the digitized output signals of an optical scanning device, characterized in that - descriptors (D) are calculated in a first module (DM) and the data relating to the descriptors are stored in a storage location of a data store (SP) which is free in each case, whereupon the data store (SP) produces an acknowledgement containing information on the storage location used, - that a second module (RM) is activated by transfer of the address information sent back and accepts this address information together with list indices from lists (L1...L4), in which arrangement the second module (RM) uses this address information for incorporating the descriptor stored in the data store (SP) into an already existing descriptor chain with an edge representative (R) or for beginning a new descriptor chain with formation of a new edge representative (R) needed for this, the descriptor chains being in each case a chaining of individual descriptors (D) with the aid of pointers (DZ), and a new descriptor (D), which is stored in an arbitrary storage location in the data store (SP), being linked to the relevant already existing chain or already existing chains by pointers, in which arrangement the list indices transferred are used for directly taking the position of the associated edge representative or edge representatives from the lists (L1...L4), and in which arrangement, when the representative of the descriptor chain is changed, this information is reentered in the lists (L1...L4) by means of the second module (RM), - that, when a completely closed edge has been formed by a descriptor chain, the second module (RM) transfers the index of this edge to a third module (OM) for further processing, - that the second module (RM), together with the information in the data store (SP), checks, on the basis of the edge index, whether the edge is an inside edge or an outside edge, - that, in the case of an inside edge, the list indices of the lists (L1...L4) are used for calling up the storage index of the representative of the enclosing outside edge from the lists (L1...L4), - that, using the index, the representative of the inside edge is appended by a pointer (IRZ) to an inside edge chain (IRK) at the representative of the outside edge in the data store (SP), - that, in the case of an outside edge, its representative is used as representative of an object, the object comprising the outside edge and all inside edges enclosed by it, and in this case the index of the representative of the complete object is forwarded to a fourth module - that the fourth module (VKLAS) makes a preliminary decision, by means of the total number of edges stored as belonging to an object, on whether the object is with certainty an image component or graphics component or not, - that, in the case of an image component or graphics component, the representative of this object is identified in the data store (SP) by being separately marked as image component or graphics component, - that the index of the representative of this marked or non-marked object is transferred to a fifth module (WM), - that attachment criteria are calculated from the outside edge of the object in this fifth module (WM), - that these attachment criteria are used for comparing the object in a manner known per se with word representatives already stored in the data store (SP), the object itself generates a new word representative in the data store (SP) or associates with other objects which are subordinate to an already existing word representative in its letter chain (BK) to form an extended word and during this process is inserted into the letter chain of this word information concerned, - that object representatives, which were marked by the module (VKLAS), in each case form a separate representative which does not associate with other words or objects, - that, by means of comparison with the index of the relevant scanning line (YA), an individual decision is made in a manner known per se for the individual word representatives on whether the word in the data store (SP) is complete and can therefore be processed further, or not, - that in the case of completeness, the index of the relevant word representative is forwarded to a sixth module (MERK), - that an attribute vector (V) of characterizing attributes is calculated from the total number of object edge representatives and descriptors subordinate to the word representative and their linking pointers (DZ) in the sixth module (MERK) and this vector is added to the word representative, - that, with forwarding the index of the word representative to a following seventh module (KLAS), the latter also compares, in accordance with a classification method known per se, reference models stored in an eighth module (REF) with the attribute vector (V) of the word representative and from the comparison makes a decision on whether the word representative is a representative of the "text", "image" or "graphics" category, - that in an output module (AUS), which is supplied with the index of the complete word representative, the entire information on this word representative stored in the data store (SP), including the information on its subordinate representatives, is made available to a further evaluating method in evaluating modules (WV), and - that one of the evaluating modules (WV) is only supplied with the index of the word representative and this module processes, by itself accessing the data store (SP), the information stored therein under the index of the relevant word representative, - that in this case the transfer to a subsequent concluding module (LOE) is delayed until the evaluating module (WV) has processed the information and reported this back to the output module (AUS), - that after the index of the word representative has been transferred in the concluding module (LOE), the completely processed representative of the word with all object and edge representatives and the relevant descriptors is erased in the data store (SP).