Abstract: A method and apparatus for debugging a hierarchically structure page description language document. As a hierarchically structured page description language is being processed, a picture/pageset stack is used to keep track of the different hierarchical levels of the document. A prologue data structure is used to keep track of various system parameters at each hierarchical level and a current context of interpretation data structure is used to keep track of system parameters as a content portion of the document is being processed. During the debugging operations, system function debugging commands can be entered which pertain to setting and deleting break points and processing of the document by the system and debugger. There are also display function debugging commands which allow a user to display any of the system parameters using the system information stored in the data structures used by the system.

Abstract: A method and apparatus for reducing the necessary size of a buffer between two cascaded decoding stages is described. The present invention includes a method and apparatus for encoding data into multiple blocks of data. The present invention also includes a method and apparatus for encoding the multiple blocks of data into multiple symbols. This encoding includes a method and apparatus for limiting the multiple symbols to a predetermined number of symbols. By limiting the symbols encoded, the buffer after the decoding stage is limited so that the size of the buffer memory to buffer decompressed data output from the decoding stage is reduced.

Abstract: A method and apparatus for conversion of a document from one format to another format. The invention inputs a binary file and determines the cleartext name for each ASN.1 tag in the binary file. An element table is used to store the features of each element and the sub-elements which are permitted to appear under each element are stored in sub-element linked list data structures referred to by the element table. It is possible for the binary encoding to be in an indefinite or definite length format and an element stack is used to keep track of the length of the binary file. The element stack is also used to keep track of the elements which are being processed in the hierarchy of the document. After a binary element is converted, the information pertaining to the cleartext representation of the binary element is stored in a double linked list data structure which refers to a previous element and a next element.

Abstract: A method and system for converting a document from a clear text representation to a binary representation. There is not a one to one correspondence between the two formats in SPDL. In order to determine what binary representation is needed for a clear text tag which can have a plurality of binary representations, it is necessary to actually process at least portions of the document for presentation (in contrast to just converting the document to a new format) in order to determine which binary representation of the tag is to be used. A stack is used to keep track of the binary elements as they are being converted. This allows for an efficient handling of the binary length encoding because the length of the binary representation of the different hierarchical levels of a document are not known until the respective hierarchical levels are encoded.

Abstract: A method and apparatus for processing the hierarchical structure of page description language. Each structure level of the document causes the creation of a prologue data structure which is used to keep track of system parameters. As content portions of the document are being processed, a current context of interpretation data structure is created which is also used to store parameters of the system. The prologue data structure and the current context of interpretation data structure contain pointers relating to context dictionaries, a user dictionary, and a state variable table. The dictionaries are kept track of by using a context stack made up by linked list data structures. It is possible to modify the search order of the context dictionaries by structure or content portions of the document and the linked list data structures keep track of whether the dictionaries were created using the content portions or structure portions.

Abstract: An improved method and apparatus for correcting for splay is provided. A document distorted by the curvature of a page of text away from a platen is converted to a digital image. The digital image is the manipulated to remove the distortion by fitting the lines of text in an unsplayed portion to a skew line, which represents the deviation of lines of text in the digital image from horizontal. Then the splay is determined for each line of text. Once the skew and the splay are determined, an inverse transformation is done to straighten the lines of text. A horizontal stretching is also applied to the text to correct for the projection angle of the original document.

Abstract: An automatic interface layout generator for database systems is disclosed herein. The automatic generator includes a specification tool for specifying a set of block descriptions representative of specified portions of a database. A block layout generator produces interface objects to be included within an interface of the database, wherein each of the interface objects corresponds to one of the block descriptions and includes a plurality of layout fields. A layout quality parameter is determined for each of the interface objects based on arrangement of the layout fields within the interface objects. A block placement generator arranges sets of the interface objects into block configurations within the interface. A placement quality parameter for each of the block configurations is derived based on a set of block placement rules and on the layout quality parameters, and a final block configuration is selected by comparing the placement quality parameters corresponding to particular block configurations.

Abstract: A method and apparatus for generating a file which conforms to the requirements of a computer language and does not require the user to type out the desired commands for a file being created. A list of commands is displayed for a user to select and when a user selects a specific command, the user is prompted for additional information concerning the command, if this information is required. The user is given choices of commands or elements which are to appear below the previously selected element or command. A stack is used to keep track of the different elements in a hierarchical structure of the computer language. When an element is first placed into a file being generated, it is pushed onto the stack. As elements below the current element in the hierarchy are being processed, they are pushed on top of the previous elements. When the elements are finished, they are popped off of and elements requiring end-tags which signify the end of the element are then inserted into the generated file.

Abstract: A method and apparatus for handling various types of dictionaries while processing a document which is written in a hierarchically structured page description language. As each hierarchical level of the document is processed, a data structure is created for keeping track of system parameters, This data structure contains pointers to dictionary link data structures which have pointers to different dictionaries. As the document is being processed, the pointers in the data structure used for keeping track of the system parameters and the pointers to the dictionary link data structures are modified to so that the dictionaries can be accurately searched for the desired key to determine the key's corresponding value.

Abstract: The present invention provides an encoding and decoding apparatus used for the compression and expansion of data. A state machine is provided having a plurality of states. Each state has at least one transition pair. Each element of the transition pair comprises zero or more bits representative of the compact code to be output and the identification of the next state to proceed to. The transition pair reflects an output for a yes and no response associated with the probability of the data to be compacted and whether the data falls within that probability.

Abstract: The present invention provides a method and apparatus for encoding and decoding data in parallel. The present invention provides a system for decompressing a data stream having multiple codewords. The system includes an input channel that receives the data stream. The system also includes a decoder which decodes each bit of the data stream, wherein at least two of the codewords in the data stream are decoded at the same time, such that the data stream is decoded in parallel.

Abstract: The invention provides an improved method and apparatus for compression of palettized images. Input symbols in an M-ary alphabet are binarized based on a context model of the input data, where the binarization is selected to provide good compression by a binary encoder. The particular binarization is determined from a reindexing table which maps each input symbol to a number of binary values. The mapping is determined from the images to be compressed, and is typically transmitted with the compressed images as overhead. The mapping is a local minimum of the bitwise entropy of the binarization. With or without reindexing the input, the symbols can be converted compressed in parallel, with the bits of the input symbols buffered and reordered as necessary to ensure that bits needed for context of a bit being decoded are available before the decompressor decodes the bit being decoded.

Abstract: An improved document matching and retrieval system is disclosed where an input document is matched against a database of documents, using a descriptor database which lists descriptors and points to a list of documents containing features from which the descriptor is derived document. The descriptors are selected to be invariant to distortions caused by digitizing the documents or differences between the input document and its match in the document database. An array of accumulators is used to accumulate votes for each document in the document database as the descriptor base is scanned, wherein a vote is added to an accumulator for a document if the document is on the list as having a descriptor which is also found in the input document. The document which accumulates the most votes is returned as the matching document, or the documents with more than a threshold number of votes are returned.

Abstract: In a character recognition system, a method and apparatus for segmenting a document image into areas containing text and non-text. Document segmentation in the present invention is comprised generally of the steps of: providing a bit-mapped representation of the document image, extracting run lengths for each scanline from the bit-mapped representation of the document image; constructing rectangles from the run lengths; initially classifying each of the rectangles as either text or non-text; correcting for the skew in the rectangles; merging associated text into one or more text blocks; and logically ordering the text blocks.

Abstract: In a character recognition system, a method and apparatus for correcting the skew of a document image. Skew correction is typically performed during segmentation of the document image into text and non-text parts. Skew correction generally involves skew angle determination and correction of the document image based on the skew angle. A skew angle is determined through the steps of: providing a set of associated rectangles representing the document image, identifying a column edge associated with the set of associated rectangles, comparing rectangles from the set of associated rectangles to identify those that are in the same column and suitably far apart, calculating a tangential angle between the rectangles identified and identifying the most common tangential angle as the skew angle.

Abstract: A method and apparatus for efficiently processing selected pages in a hierarchically structured page description language. A stack is used to keep track of the different hierarchical levels of a document. The hierarchical levels which select pages have corresponding FIFO data structures which are used to keep track of the selected pages at the different hierarchical levels. After a selected range of pages is processed, that range of pages is popped out of the selection page range FIFO data structure. When a hierarchical level is finished being processed, the entry in the stack corresponding to that hierarchical level is popped off of the stack.

Abstract: A method and apparatus for processing resources in a hierarchically structured page description language. The resource must first be defined before it can be used. The definition of a resource is contained in a resource specification. The resource is defined by creating a linked list resource definition data structure which contains a reference to a resource specification and a reference to a subsequent resource definition data structure. Alternatively, the resource can be defined by downloading a predefined resource from non-volatile memory and reference is made to the downloaded resource specification in a AVAILABLE RESOURCE TABLE. It is also possible for default resources of the system to be found in the AVAILABLE RESOURCE TABLE. After a resource is defined, it must be declared. The declaration process uses a resource declaration data structure which has a reference to a defined resource specification and a reference to a subsequent resource declaration data structure.

Abstract: A converter for reading image bands in block order and outputting the image bands in raster order or vice versa is provided, including a band memory for storing a number of pixels equal to the number of pixels in an image band, an array of counters coupled to an address input of the band memory, a carry signal router, and a state machine. The carry signal router routes the carry out lines of the counters to the carry in lines of the counters in a pattern where the counters are ordered from a most significant to a least significant and the carry signal router ensures that each of the carry out lines of each counter is coupled to the carry in lines of the next most significant counter, with the carry out line of the most significant counter being input to a state machine and the carry in line of the least significant counter being a clock or divided clock input.

Abstract: Communication system and method including a calling apparatus and a called apparatus. The system comprises handshake means for exchanging negotiation information including error correction ECM capabilities data, contained in a plurality of command frames between the calling apparatus and the called apparatus. The system further includes means for initiating an error correction operation, a transmitter for transmitting and receiving between the calling and the called apparatus a data set having associated data frame identification information, and verification means for verifying receipt of the data set. A method corresponding to the system also is described.

Abstract: A method and system to efficiently and automatically determine whether a document to be processed and printed has been encoded in a binary or clear text representation of a page description language. The document is initially processed as if it were binary encoded and the first three tags of the document are examined to determine if they contain the object identifier having the value "28 CF 44 00 H". If one of the first three tags has this value, an encoding flag is set to indicate the document is a binary SPDL file and the recognition process is terminated. If the document is determined not to be a binary SPDL file it is examined to see if it is clear text SPDL file. The beginning of the document is examined to determine if it contains zero or more S separators which are defined to be spaces, carriage returns, line feeds, and tabs followed by the characters "<!DOCTYPE" regardless of capitalization followed by one or more S separators followed by the characters "SPDL".