United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,623,556
`
`Murayama et al.
`
`[45] Date of Patent:
`
`Apr. 22, 1997
`
`US005623556A
`
`.............................. .. 382/56
`4,700,402 10/1987 Okai et al.
`4,725,815
`2/1988 Mitchell et al.
`358/261.3
`4,748,512
`S/1988 Armstrong . . .. .
`.. . .. 358/261.1
`Ea‘°
`------
`~----
`CB 6
`.
`.
`.
`11/1989 Arimoto etal.
`. 358/261.1
`2/1992 Abe et al.
`............................. .. 358/453
`
`
`
`,
`,
`4,884,147
`5,086,434
`
`[54] SYSTEM AND METHOD OF EXTRACTING
`BINARY ]1\1AGE DATA
`
`[75]
`
`Inventors: Masayoshi Murayama; Shigehiro
`"
`.
`'
`flmutaka saw’ an °f
`
`’
`
`P
`
`[73] Assignee: Kabushiki Kaisha Toshiba, Kawasaki,
`J
`apan
`[21] Appl. No.: 368,719
`
`FOREIGN PATENT DOCUMENTS
`63-33350
`7/1988
`Japan .
`OTHER PUBLICATIONS
`
`[22] Filed:
`
`Jan. 4, 1995
`
`Related U.S. Application Data
`
`Japanese Patent Publication No. 63-33350 Hitoshi Miyai et
`al., “Coded Image Storage Apparatus,” (NEC Corporation),
`published Jul, 5, 1988,
`
`[63] Continuation of Ser. No. 108,292, Aug. 19, 1993, aban—
`doned, which is a continuation of Ser. No. 737,030, Jul. 29,
`1991: aba“d°“°d-
`Foreign Application Priority Data
`
`[30]
`
`Primary Examiner—MiChae1T-Razavi
`Assistant Examiner—Jon Chang
`Attorney, Agent, or Firrn—Finnegan, Henderson, Farabow,
`G335“ & Dunner: L-L-R
`
`Jul. 31, 1990
`
`[JP]
`
`Japan .................................. .. 2.201539
`
`[57]
`
`ABSTRACT
`
`Int. CL6 ....................................................... G06T 9/00
`[51]
`[52] U.S. Cl.
`.............. ..
`382/233; 358/261.4
`
`[58] Field of Search .............................. 358/261.1, 261.3,
`353/261.4’ 261.2, 4327 453; 382/56’ 232’
`245’ 233
`
`[55]
`
`References cited
`
`U.S. PATENT DOCUMENTS
`
`For each of multiple segments acquired by dividing a binary
`image by a predetermined under of lines. image data of a
`reference line eerfeepending *0 a Start line 01° that Segment
`' is stored in an intermediate start table in association with
`data indicating a head coding position of the start line in
`code data acquired when the binary image is compressed.
`Based on the stored data, partial
`image extraction is
`executed.
`
`3,723,641
`
`3/1973 Heinrich et al.
`
`..................... 358/261.4
`
`'
`
`5 Claims, 3 Drawing Sheets
`
`REFERENCE ‘LINE
`IMAGE DATA
`
`
` EXTERNAL
`
`STORAGE
`UN IT
`
`
`
`,4 DECODING
`CIRCUIT
`
`35
`
`37
`
`
`
`
`N(D
`
`GENERATING
`CIRCUIT
`
`SYSTEM BUS
`
`28
`
`
`
`Apple 1034
`
`U.S. Pat. 9,189,437
`
`Apple 1034
`U.S. Pat. 9,189,437
`
`

`
`U.S. Patent
`
`Apr. 22, 1997
`
`Sheet 1 of 3
`
`655,325,5
`
`mm
`
`._<zmm:xm_
`
`5
`
`m_w<m8.mI
`
`._._ZD
`
`mm>mosm_s_H
`
`pm
`
`mam_2m+m>m
`
`mm
`
`mmfiz_o¢
`
`mmn_..5m
`
`VNm_
`
`
`
`::om_o.3ozaooma
`
`+2_on_omozqzo
`
`tooma
`
`0Z_._.Um:.mQN_
`
`
`
`
`
`m.__n_mmemamm.::um_o
`
`O\H
`
`o2_Emmzmo
`Em._.Z_On_mm
`mmumnm
`
`
`
`M23mozmmmrmm
`
`<._.<Qmos):
`
`+.mV_.m
`
`mm
`
`IvEosmz
`n.<_2Cm
`
`mmpzaoo
`mz_._mm
`
`
`
`
`
`
`

`
`U.S. Patent
`
`Apr. 22, 1997
`
`Sheet 2 of 3
`
`5,623,556
`
`30
`
`4o
`
`POSITION 0
`
`30-1
`
`nLlNES
`
`40-4
`
`1
`
`2
`
`30-3
`
`3
`
`POSITION 4
`
`POSITION 2
`
`.
`
`LINES
`
`POSITION 3
`
`40-3
`
`F IG. 2
`
`F I G. 3
`
`
`
`
`
`
`CODE START
`.
`POSITION
`REFERENCE LINE
`505
`
`
`
`
`
`
`
`FIG. 4
`
`

`
`U.S. Patent
`
`Apr. 22, 1997
`
`Sheet 3 of 3
`
`5,623,556
`
`PROCESSING SECTION
`
`REEERENCE LINE IMAGE
`
`-3
`
`0
`
`R0
`
`8
`
`RI
`
`I6
`
`R2
`
`60
`
`~
`
`FUNNEL SHIFTER
`
`70
`
`bI DETECTOR
`
`80
`
`ADDER
`
`5‘
`
`O0-"-O/{I---I
`
`gt 8*
`1‘ 0*
`[008
`5
`--
`
`IIIIIIIISZ
`IIIIII
`
`OUTPUT
`IMAGE
`
`GENERATING SECTION
`
`F ICE.
`
`E3
`
`

`
`1
`
`SYSTEM AND METHOD OF EXTRACTING
`BINARY l1\/IAGE DATA
`
`This application is a continuation of application Ser. No.
`08/108,292, filed Aug. 19, 1993, now abandoned which is a
`continuation of application Ser. No. 07/737,030, filed Jul.
`29, 1991, now abandoned.
`
`5
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to a binary image data
`extracting a system and method for extracting part of large
`image data in a binary image compression/expansion appa-
`ratus.
`
`2. Description of the Related Art
`
`A binary image compression/expansion apparatus han-
`dling a great amount of binary image data usually encodes
`binary image data to speed up the data transfer. Typical
`coding systems used for this type of apparatus are the MH
`(Modified Huffman) system, MR (Modified Read) system
`and MMR (Modified MR) system.
`To extract part of image data from a binary image coded
`by the MH, MR or MMR coding system, all code data are
`expanded and developed into the original image before the
`extraction.
`
`According to the above method, however, a large amount
`of image data which does not directly concern the extraction
`must be developed. As the original image becomes larger,
`therefore, image expansion takes more time, and the image
`memory needs a larger capacity.
`Examined Japanese Patent Publication No. 63-33350 dis-
`closes a method for dividing a binary image into segments
`and encoding a head line of each segment in the one-
`dirnensional coding system. This method carmot however be
`used with the MMR system which encodes binary image
`data with every line having a correlation with multiple lines.
`This method also carmot cope with the MR system if the
`head line of each segment is coded in a two-dimensional
`coding system.
`
`20
`
`25
`
`30
`
`35
`
`SUMMARY OF THE INVENTION
`
`It is therefore an object of the present invention to provide
`a binary image extracting system and method capable of
`quickly extracting part of even a large binary image based on
`code data.
`
`To achieve this object, a system for compressing and
`expanding a binary image according to the first aspect of the
`present invention comprises: means for dividing the binary
`image into multiple segments by a predetermined number of
`lines; coding position data storing means for storing image
`data of a reference line corresponding to a start line of each
`of the divided segments, in association with that data in code
`data acquired when the binary image is compressed which
`indicates a head coding position of the start line; and means
`for producing an image based on the data stored in the
`coding position data storing means.
`A system for compressing and expanding a binary image
`according to the second aspect of the present invention
`comprises: means for dividing the binary image into mul-
`tiple segments by a predetermined number of lines; coding
`position data storing means for storing image data of a
`reference line corresponding to a start line of each of the
`divided segments, in association with that data in code data
`acquired when the binary image is compressed which indi-
`
`50
`
`55
`
`65
`
`5,623,556
`
`2
`
`cates a head coding position of the start line; and means for
`extracting part of the binary image based on the data stored
`in the coding position data storing means.
`
`A system for compressing and expanding a binary image
`according to the third aspect of the present invention com-
`prises: binary image compressing/expanding 10 means for
`executing a compressing process to produce code data based
`on data of a binary image and an expanding process to
`produce a binary image based on the code data; means for
`dividing the binary image into multiple segments by a
`predetermined number of lines based on data acquired by
`processing done by the binary image compressing/expand-
`ing means; coding position data storing means for storing
`image data of a reference line corresponding to a start line
`of each of the divided segments, in association with that data
`in the code data acquired when the binary image is com-
`pressed which indicates a head coding position of the start
`line; code data storing means for storing code data to be
`handled in the binary image compressing/expanding means;
`and means for extracting and expanding the code data stored
`in the code data storing means to produce an image, based
`on the data stored in the coding position data storing means
`at a time the binary image compressing/expanding means
`extracts part of the binary image.
`According to the present invention, since image data of a
`reference line corresponding to the start line of an image
`segment is stored in a memory in association with that data
`in code data which indicates the head coding position of the
`start line, the image data of the reference line can be referred
`to when extracting part of an image or expanding image data
`corresponding to the desired extraction area. This feature
`can permit the use of the MMR system as well as the
`two-dimensional coding line in the MR system.
`In particular, the binary image compressing/expanding
`means is designed to skip reading code data stored in the
`code data storing means to avoid expanding the unnecessary
`data, thus speeding up the image extraction.
`The coding position data storing means stores image data
`of the reference line and data indicating the head coding
`position of the start line in the compressing process or
`expanding process based on the contents of line number
`holding means, byte number counting means, bit position
`holding means, reference line holding means and line num-
`ber counting means all provided in the binary image com-
`pressing/expanding means.
`Additional objects and advantages of the invention will be
`set forth in the description which follows, and in part will be
`obvious from the description, or may be learned by practice
`of the invention. The objects and advantages of the invention
`may be realized and obtained by means of the instrumen-
`talities and combinations particularly pointed out in the
`appended claims.
`
`BRIEF DESCRIPTION OF THE DRAWDIGS
`
`The accompanying drawings, which are incorporated in
`and constitute a part of the specification, illustrate a pres-
`ently preferred embodiment of the invention, and together
`with the general description given above and the detailed
`description of the preferred embodiment given below, serve
`to explain the principles of the invention.
`FIG. 1 is a block diagram illustrating the structure of a
`binary image compressing/expanding apparatus in a system
`using a binary image data extracting system according to
`one embodiment of the present invention;
`
`

`
`3
`
`4
`
`5,623,556
`
`FIG. 2 is a conceptual diagram showing image data
`associated with an original image;
`FIG. 3 is a conceptual diagram of two-dimensionally
`arranged code data associated with the image data shown in
`FIG. 2;
`
`FIG. 4 is a conceptual diagram of an intermediate start
`table; and
`
`FIG. 5 is a detailed block diagram showing a generating
`circuit shown in FIG. 1.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODHVIENTS
`
`FIG. 1 is a block diagram illustrating the structure of a
`binary image compression/expansion apparatus in a binary
`image data extracting system according to the present inven-
`tion.
`
`As shown in FIG. 1, a binary image compression/expan-
`sion apparatus 10 comprises a changed point detecting
`circuit 12, a decoding circuit 14, a generating circuit 16, an
`I/O register file 18, a byte counter 20, a line counter 22,
`pointer buffers 24 and 26 and a reference line image memory
`27. The binary image compression/expansion apparatus 10
`is connected via a system bus 28 to a CPU 33.
`This system is provided with a memory 35, which stores
`code data to be sent to the binary image compression/
`expansion apparatus 10 in image expansion and which stores
`information as an intermediate start table 50 (code data
`storing means) to be described later. Image data used for
`compressing an image will be sent to this system by an
`image input apparatus (not shown), such as an ITV.
`The changed point detecting circuit 12 detects a changed
`point from image data on a line (reference line) immediately
`before a line stored in the reference line image memory 27
`to be decoded or encoded. The decoding circuit 14 receives
`codes (code data) at the time of image expansion, or image
`data at the time of image compression, and decodes the data.
`Based on the changed point detected by the changed point
`detecting circuit 12 and the result of data decoding done by
`the decoding circuit 14, the generating circuit 16 generates
`image data in the image expansion, and generates code data
`in the image compression. The changed point detecting
`circuit 12 and the generating circuit 16 are described in
`detail
`in Unexamined Japanese Patent Publication No.
`62-61980 filed by the same assignee as that of this applica-
`tion. FIG. 5 exemplifies the structure of the generating
`section of the binary image compression/expansion appara-
`tus. In the following description, “a ” designating a changed
`point with its position described by the immediately previ-
`ous code word, and “al” is the first changed point on the
`right side of a0 on the coded line, whose position designates
`to be coded. “bl” is a changed point on the right side of a0
`on the reference line, and changed in the same direction as
`al (from white to black, or vice versa). “8” is a relative dot
`position. The changed point is where a dot is inverted from
`white to black, or vice versa. The reference line is a scan line
`immediately before a scan line (coding line) to be coded.
`Part of the image data on the reference line is held in
`registers R2 to R0. Runs are generated in registers Q1 and
`Q0. “a” (pointer) specifies the position where generation of
`the run in the Q0 register starts. Reference line data right to
`a is fetched from a funnel shifter 60. Then the data is sent to
`a bl detector 70 to acquire the bit position of the b1 bit.
`Further, an adder 80 calculates the last position of the run to
`be generated, i.e., adds bl, 5 and a to obtain the position of
`al.
`
`Linking the runs will now be explained. The pointer a in
`the Q0 indicates the position where generation of the run
`starts. On the left side of a is the run already generated. A
`selector S2 selects the Q0 register. The selector S2 selects
`the Q0 register for the data on the left side of a. The selector
`S2 sends a and the data on the right side of a as “O” to the
`Q0 register in generating a white run, and sends them as “l”
`in generating a black run. The Q1 register receives “O”
`(white) or “l” (black) both to be generated.
`When the bl bit is not detected an 8-bit run is generated
`with its last data in the Q1 register. Q0 is output in the next
`cycle, which completes the generation of the run. The
`selector S2 selects the Q1 register, and the run generation is
`repeated. The reference line data is moved from registers R2
`‘and registers R1 to R1 and R0, respectively, and the next
`data is sent to register R2.
`When bl bit is detected, the run has already generated up
`to one dot before the position indicated by the out-put al of
`the adder. With the output of the adder renewed as “a,” white
`and black runs are inverted, and processing to generate the
`next run is executed. Since the reference line is scanned in
`synchronism with the image generation, an image is pro-
`duced in parallel to the detection of the bl bit.
`The I/O register file 18 holds various data used for the
`compression/expansion process in the binary image com-
`pression/expansion apparatus 10. This I/O register file 18
`- includes registers (line number holding means) which set the
`number of lines, n, for dividing an image into multiple
`segments. In the image expansion,
`the byte counter 20
`counts the number of bytes of code data, starting with the
`head byte of that data. When the image is expanded, the
`pointer buffer 24 indicates the head bit position of the code
`in the code data where the decoding circuit 14 should start
`decoding. The line counter 22 counts the number of the lines
`up to the line number n for the divided segments set in the
`I/O register file 18. When the image is compressed, the
`pointer buffer 26 indicates the head bit position where the
`codes of code data are to be linked together to the generating
`circuit 16. The reference line image memory 27 holds image
`data of the reference line. The reference line image memory
`27 and the point buffer 24 are connected to external units by
`buses, so that they can be accessed for data reading/writing
`through the buses. Likewise,
`the byte counter 20,
`line
`counter 22 and point buffer 26 are connected to external
`units by buses so as to be accessible for data read/write
`operation through the buses. An external storage unit 31 for
`storing code data is connected to the system bus 28, and a
`bit map memory 41 is connected via an image bus 39 to the
`generating circuit 16. There is therefore an exclusive display
`pipeline so that, at
`the time the expansion of data is
`executed, the code data from the external storage unit 31 is
`expanded by the binary image compression/expansion appa-
`ratus 10 and the image data is stored in the bit map memory
`41. Also connected to the system bus 28 is a read only
`memory (ROM) 37 which stores firmware as coding posi-
`tion setting means to be described later.
`The data structure in this embodiment will be described
`
`below. FIG. 2 shows image data which is divided into
`multiple segments, each segment having a predetermined
`number of lines, n. FIG. 3 shows the start position of code
`data in each segment. FIG. 4 illustrates an intermediate start
`table which stores reference line image data of the start lines
`in each segment and the start byte positions and bit positions
`of codes.
`
`FIG. 3 illustrates the start positions of code data 40 in
`association with image data 30 shown in FIG. 2. In general,
`
`20
`
`25
`
`30
`
`35
`
`40
`
`50
`
`55
`
`60
`
`65
`
`45’
`
`

`
`5,623,556
`
`5
`
`coded data, even when acquired by coding image data of the
`same length, has dilferent lengths depending on the contents
`of the image data. There is no regularity on the coded data
`for the head positions (0, 1, 2 .
`.
`. ) of each divided segment
`40-1, 40-2, .
`.
`.
`. The intermediate start table 50 shown in
`FIG. 4 stores the reference line corresponding to the head
`line of each divided segment 30-1, 30-2, .
`.
`. in the image
`data 30 in FIG. 2 in association with the byte position from
`the head in the code data 40 which indicates the head
`position (code start position) of each divided segment 40-1,
`40-2 .
`.
`. shown in FIG. 3 and the bit position in that type.
`It is assumed that the image data of the reference line
`corresponding to the head line (coding line) in the first
`segment 30-1 has all the bits of the “O” indicating “white.”
`In the intermediate start table 50, the divided segments of
`the image data 30 are associated one to one with code data.
`In partially extracting an image from, for example, com-
`pressed image data, once the divided segment including the
`panial image to be extracted from the image data 30 is
`determined, is obtained from intermediate start table 50 the
`code start position of that segment in the code data 40 and
`decoding starts from that address. When decoding for the
`necessary number of lines is completed, the decoding will be
`terminated, thus ensuring elficient extraction of the required
`data.
`
`The operation of this embodiment will now be described.
`In the following description,
`the operation of partial
`expanding process (extraction of a partial image) in the
`binary image compression/expansion apparatus 10 will be
`explained referring to FIGS. 1 to 4.
`To begin with, a description will be given of how to
`prepare the intermediate start table 50 in FIG. 4. First, the
`I/O register file 18 is accessed, and the number of lines, n,
`in the divided segment in the image data 30 is set. Interme-
`diate start table 50 is prepared at the time of image com-
`pression when the original data is image data, and at the time
`of image expansion when the original data is code data.
`when the image data or code data is input to the binary
`image compression/expansion apparatus 10, or more spe-
`cifically, to the decoding circuit 14 therein, the compression
`process or expansion process is sequentially executed. Every
`time processing for one line is executed, the line counter 22
`counts the number of lines processed. The byte counter 20
`counts the number of bytes of the prepared code data (at the
`time of image compression) or the number of bytes of the
`input code data (at the time of image expansion).
`when the count value of the line counter 22 reaches a
`
`value indicating the end of the processing for a predeter-
`mined number of lines (n), the binary image compression!
`expansion apparatus 10 issues a CPU interrupt. At the time
`of image compression, the contents of the pointer bufier 26
`specify the head bit position where codes of the next line
`should be linked. At the time of image expansion,
`the
`contents of the pointer buifer 24 specify the head bit position
`(code start position) where decoding for the next line should
`start.
`
`the
`In response to an I/O command from the CPU,
`reference line data as well as the contents of the byte counter
`20 and the contents of the pointer buffer 26 (at the time of
`image compression) or the contents of the pointer buffer 24
`(at the time of image expansion) are fetched via the system
`bus 28. On the system side, data read out from the binary
`image compression/expansion apparatus 10 is sequentially
`stored in the intermediate start table 50. Here, the reference
`line data is image data of the reference line corresponding to
`the head line in the next divided segment to be processed.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`6
`The image data of the reference line is associated with the
`byte position from the head in the code data 40 and the bit
`position in that byte. The code data 40 originating from the
`compression/expansion process according to the contents of
`the intermediate start table 50 is also held (see FIG. 3).
`Then, the processing in the binary image compressionl
`expansion apparatus 10 resumes. As the above-described
`processing is continuously performed for the entire image
`data,
`the intermediate start
`table 50 for the individual
`divided segments of the whole image is prepared.
`A description will be given below of a specific operation
`to execute a partial expanding process (extraction of partial
`image) using the intermediate start table 50.
`Extraction and expansion of image data are executed by p
`reading out the code data 40, and data from the intermediate
`start table 50. The expanding process is executed starting
`with the divided segment preceding and closest
`to the
`desired extraction segment. Before the expansion process
`starts, therefore, the image data of the reference line corre-
`sponding to the head line in that divided segment and the
`code start position corresponding to this data are read out
`from the intermediate start table 50. The read-out pieces of
`data are sent over the system bus 28 to the binary image
`compression/expansion apparatus 10. In response to an I/O
`command from the CPU, the binary image compressionl
`expansion apparatus 10 stores the image data of the refer-
`ence line into the reference line image memory 27, and sets
`the byte position indicating the code start position and the bit
`position in that byte into the byte counter 20 and pointer
`buffer 24, respectively.
`when the expanding process is invoked and the code data
`40 is input to the coding circuit 14, the byte counter 20
`counts down for each l-byte input. Reading of the input
`code data is skipped until the value of the byte counter 20
`becomes “0.” That is, no expanding process will be per-
`formed for the unnecessary code data located before the
`divided segment which includes the image to be extracted.
`When the code data is input piece by piece and the value of
`the byte counter 20 becomes “O,” the byte including the head
`code data in the segment desired for image expansion has
`been fetched. The pointer buffer 24 now indicates the
`position in the same byte where decoding should start.
`The changed point detecting circuit 12 detects a changed
`point of the reference line corresponding to the coding line
`(the head line in the divided segment) based on the reference
`line data stored in the reference line image memory 27. The
`decoding circuit 14 decodes data from the decoding start
`position specified by the contents of the pointer buffer 24.
`The generating circuit 16 produces an image in accordance
`with the result of the detection of the changed point in the
`detecting circuit 12 and the result of the decoding in the
`decoding circuit 14.
`Thereafter, images are sequentially produced in accor-
`dance with the input code data. It is to be noted that the
`expansion process is executed only for the divided segment
`which includes a partial
`image to be extracted. When
`decoding of the necessary number of lines is completed in
`the middle of processing one divided segment, the expan-
`sion process will be terminated there.
`In this manner,
`the image data of the reference line
`corresponding to the head line is stored in the intermediate
`start table 50 in association with information representing
`the code start position for each of multiple segments
`acquired by dividing an image by n lines. In extracting a
`partial
`image,
`therefore,
`the expansion processing is
`executed only for the divided' segment that includes the
`
`

`
`7
`
`8
`
`5,623,556
`
`partial image, based on the information in the table 50 which
`represents the code start position. As this system does not
`perform the expansion process for a vast amount of image
`data which does not directly concern image extraction, the
`partial image can be efficiently extracted without requiring
`a large-capacity image memory. Since the intermediate start
`table 50 holds the image data of the reference line in
`association with theinfonnation that indicates the code start
`position, the use of this data permits this embodiment to be
`applied to a system which codes data using the MMR
`system. Further, even in the MR system, it is unnecessary to
`limit
`the start
`line of each divided segment
`to a one-
`dimensional
`line. In addition,
`this embodiment may be
`modified so that the system side sends code data correspond-
`ing to the coding position stored in the intermediate start
`table to the binary image compression/expansion circuit
`which starts the expansion process immediately upon recep-
`tion of the data. In this case, no counter is needed to skip
`reading the code data. Additional advantages and modifica-
`tions will readily occur to those skilled in the art. Therefore,
`the invention in its broader aspects is not limited to the
`specific details,
`representative devices, and illustrated
`examples shown and described herein. Accordingly, various
`modifications may be without departing from the spirit or
`scope of the general inventive concept as defined by the
`appended claims and their equivalents.
`What is claimed is:
`
`1. A system which sequentially updates one of a plurality
`of lines of a binary image, which is part of an entire binary
`image, as a line for processing and generates an image of the
`line on the basis of relationships between the line and a
`reference line which immediately precedes the line in the
`binary image, said system comprising:
`expanding means for expanding code data to produce the
`binary image based on binary image data of a reference
`line corresponding to a line to be expanded and based
`on data indicating a start position of the code data to be
`processed, the code data being a result of a compression
`of the entire binary image;
`an intermediate start table for storing a plurality of data
`pairs, each of which is made up of image data of a
`reference line corresponding to a start line of one of a
`plurality of segments and coding position data corre-
`sponding to a head position of said one of the plurality
`of segments, the plurality of segments being obtained
`by dividing the entire binary image into a plurality of
`lines, the coding position data indicating a head coding
`position corresponding to a head position of each of the
`segments included in the code data obtained when the
`entire binary image is compressed;
`code data storing means for storing the obtained code
`data; and
`
`control means for transferring a pair of the binary image
`data of the reference line and the coding position data,
`both of which are stored in said intermediate start table,
`to said expanding means and for causing said expand-
`ing means to expand the code data, which corresponds
`to the segments stored in the code data storing means.
`2. A system which sequentially updates one of a plurality
`of lines of a binary image, which is part of an entire binary
`image, as a line for processing and generates an image of the
`line on the basis of relationships between the line and a
`reference line which immediately precedes the line in the
`binary image, said system comprising:
`means for compressing binary image data to yield code
`data;
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`means for expanding the code data to produce the binary
`image, both the expanding and compressing based on a
`binary image data of a reference line corresponding to
`a line to be compressed and to be expanded and on data
`indicating a head position of the code data to be
`processed;
`an intermediate start table in a memory for storing a
`plurality of data pairs, each of which is made up of
`image data of the reference line corresponding to a start
`line of one of a plurality of segments and coding
`position data corresponding to a head position of said
`one of the plurality of segments, the plurality of seg-
`ments being obtained by dividing the entire binary
`image into a plurality of lines, the coding position data
`indicating a head coding position corresponding to a
`head position of each of the segments included in code
`data obtained when the entire binary image is com-
`pressed;
`code data storing means for storing the obtained code
`data; and
`
`control means for transferring a pair of the binary image
`data of the reference line and the coding position data,
`both of which are stored in said intermediate start table,
`to said binary image compressing means or expanding
`means and for causing said means for expanding the
`binary image data to expand the code data, the code
`data corresponding to the segments being stored in the
`code data storing means.
`3. A system according to claim 2, wherein said binary
`image compressing/expanding means includes:
`reference line setting means for setting image data of said
`reference line of said start line of a segment immedi-
`ately preceding and closest
`to a segment
`to be
`extracted;
`
`coding position setting means for setting a head coding
`position of said start line corresponding to said refer-
`ence line set by said reference line setting means; and
`means for skipping reading said code data stored in said
`code data storing means up to said coding position set
`by said coding position setting means, and expanding
`code data following a start position referring to said
`image data of said reference line set by said reference
`line setting means, thereby producing a partial image.
`4. A system according to claim 3, wherein said binary
`image compressing/expanding means further comprises:
`line number holding means for holding a line number for
`each of said divided segments of to-be-produced said
`binary image;
`byte counting means for counting a number of bytes of
`processed code data;
`bit position holding means for holding a head bit position
`of a code where processing should start;
`reference line holding means for holding image data of a
`reference line corresponding to a line to be processed;
`line number counting means for counting a number of
`lines processed; and
`means for storing said image data held in said reference
`line holding means and coding-position indicating data,
`specified by said number of bytes counted by said byte
`counting means and said head bit position held in said
`bit position holding means, into said coding position
`data storing means, when said number of lines counted
`by said line number counting means and to be subjected
`to a compressing process reaches said line number held
`in said line number holding means at a time of data
`compression.
`
`

`
`9
`
`10
`
`5,623,556
`
`5. A system according to claim 2, wherein said binary
`image compressing/expanding means comprises:
`line number holding means for holding a line number for
`each of said divided segments of said to-be-produced
`binary image;
`byte counting means for counting a number of bytes of
`processed code data;
`
`bit position holding means for holding a head bit position
`of a code where processing should start;
`reference line holding means for holding image data of a
`reference line corresponding to a line to be processed;
`line number counting means for counting a number of
`lines processed; and
`
`means for storing said image data held in said reference
`line holding means and coding-position indicating data,
`specified by said number of bytes counted by said byte
`counting means and said head bit position held in said
`bit position holding means, into said coding position
`data storing means, when said number of lines counted
`
`by said line number counting means and to be subjected
`to an expanding process reaches said line number held
`in said line number holding means at a time of expand-
`ing already-coded code data.
`
`*
`
`*
`
`*
`
`*
`
`*
`
`

`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO.
`
`:
`
`5'623'556
`
`rnvsunm