GB2388944A - Bitmap font data storage within data processing systems - Google Patents
Bitmap font data storage within data processing systems Download PDFInfo
- Publication number
- GB2388944A GB2388944A GB0314835A GB0314835A GB2388944A GB 2388944 A GB2388944 A GB 2388944A GB 0314835 A GB0314835 A GB 0314835A GB 0314835 A GB0314835 A GB 0314835A GB 2388944 A GB2388944 A GB 2388944A
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- GB
- United Kingdom
- Prior art keywords
- pictograph
- pixel
- character
- bitmap
- entropy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F40/00—Handling natural language data
- G06F40/10—Text processing
- G06F40/103—Formatting, i.e. changing of presentation of documents
- G06F40/109—Font handling; Temporal or kinetic typography
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
- H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
- H03M7/40—Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code
- H03M7/42—Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code using table look-up for the coding or decoding process, e.g. using read-only memory
Abstract
Efficiently compressing pictograph pixel bitmap font data using entropy encoding, in particular Huffman codes. The bitmap of a pictograph character (6, Fig. 4) is divided into a plurality of smaller (e.g. four by two) pixel tiles (38, Fig. 4), 40. The 8-bit codes representing the tiles are replaced by Huffman codes, 44, with the frequently occurring tiles being given the short Huffman codes. A stream of Huffman codes is generated, being a variable length coded representation of the original pictograph pixel bitmap. The corresponding decoding process, Fig. 6, is described. A two level table lookup access method is also described, for determining an address (8, Fig. 2) within the variable length coded data stream of pixel data (10, Fig. 2) for the whole font relevant to the character concerned (6, Fig. 4).
Description
1 2388944
5 BITMAP FONT DATA STORAGE WITHIN DATA PROCESSING SYSTEMS
This invention relates to the storage of bitmap font data within data processing systems. Within data processing systems text data is typically stored as a sequence of lo character codes. When it is desired to present the text data to a user, for example by displaying it on a screen or printing it, then it is necessary to convert each character code into a graphical form that can be presented to a user. This conversion uses font data that specifies a graphical form for each character code. One type of font data is that in which a bitmap representation of the character is stored for each character 5 code. Such bitmaps can be relatively simply processed for display or printing.
problem that arises in such systems is the amount of storage capacity utilised in storing the font data and any associated data for accessing that font data.
The amount of memory resource consumed can be a particular problem in the case of pictograph characters (such as Chinese, Korean and Japanese characters) where the 20 number of characters that need to be represented can be very high' e.g. a Chinese pictograph font may include 13,000 different pictograph characters.
Measures that can reduce the amount of storage capacity needed to deal with font data are strongly desirable.
Viewed from one aspect the invention provides apparatus for decompressing 25 pictograph font data for a pictograph character, uncompressed data for said pictograph character being in the form of an N by M pixel bitmap, said apparatus comprising: an entropy decoder for entropy decoding a plurality of entropy codes each representing a P by Q pixel bitmap to generate a plurality P by Q pixel bitmaps for said pictograph character; and so logic for combining said plurality of P by Q pixel bitmaps to generate said N by M pixel bitmap for said pictograph character.
Pictograph fonts typically have very high numbers of characters. Furthermore, each individual character may be highly complex in shape so requiring a relatively detailed bitmap to properly represent it. The invention recognises that whilst 3 5 pictograph characters may be highly complex in shape, there is in practice considerable redundancy within their form and that, if the characters are divided into smaller tiles, then certain forms of tile occur many times more frequently than others.
5 The invention exploits this phenomenon by using entropy coding to represent each tile such that commonly occurring tiles can be given small entropy code with infrequently occurring tiles being given longer entropy codes. In this way' an increased degree of data compression can be achieved compared to merely raster scanning the character bitmap and compressing the bit stream resulting therefrom. Huffmn coding is a o particularly suitable form of entropy encoding to use for this purpose.
An aspect ratio of two to one for the P by Q pixel bitmap tiles has been found to be particularly suitable. Individual pictograph character bitmaps having a size of 16 by 16 pixels or 24 by 24 pixels provide a good compromise between the detail that is able to be displayed and the amount of storage capacity needed.
In an analogous way to the discussion mentioned above, it will be appreciated that the Huffman decoder and the logic for combining required by the decompression technique of the invention may conveniently be provided by a general purpose data processor operating under software control.
Viewed from a complementary aspect the present invention provides apparatus so for compressing pictograph font data for a pictograph character, uncompressed data for said pictograph character being in the form of an N by M pixel bitmap, said apparatus comprising: logic for dividing said N by M pixel bitmap for said pictograph character to generate a plurality of P by Q pixel bitmaps; and 2s a entropy encoder for entropy encoding each of said plurality P by Q pixel bitmaps for said pictograph character as an entropy code to generate a plurality of entropy codes representing said pictograph character.
Viewed from another aspect the present invention provides a method of decompressing pictograph font data for a pictograph character, uncompressed data for 30 said pictograph character being in the form of an N by M pixel bitmap, said method comprising the steps of: entropy decoding a plurality of entropy codes each representing a P by Q pixel bitmap to generate a plurality P by Q pixel bitmaps for said pictograph character; and combining said plurality of P by Q pixel bitmaps to generate said N by M pixel 35 bitmap for said pictograph character.
Viewed from another aspect the present invention provides a method of compressing pictograph font data for a pictograph character, uncompressed data for
a, 3 f s said pictograph character being in the form of an N by M pixel bitmap, said method comprising the steps of: dividing said N by M pixel bitmap for said pictograph character to generate a plurality of P by Q pixel bitmaps; and entropy encoding each of said plurality P by Q pixel bitmaps for said lo pictograph character as an entropy code to generate a plurality of entropy codes representing said pictograph character.
It will be appreciated that whilst the table indexing arrangement and the tiling with entropy coding could be used separately, they together provide a particularly improved system.
An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 illustrates the relationship between a font character code, variable length coded data for that font character code and a visual representation of that font character code; 20 Figure 2 illustrates a technique for mapping an A-bit font character code to a storage location within a memory holding variable length coded data representing a pixel bitmap of that character; and Figure 3 is a flow diagram illustrating the operation of the system of Figure 2; Figure 4 illustrates a pictograph character bitmap and its division into tiles as prior to Huffman coding; Figures S and 6 are flow diagrams respectively illustrating the compression and decompression of a pictograph character; and Figure 7 illustrates a general purpose data processing system for performing the techniques described in relation to Figure 1 to 6.
30 Figure I illustrates a character code 2 representing a font character within a pictograph font. The pictograph font is a Chinese character font and may typica!!y include approximately 13,000 characters. For this reason, a two byte character code 2 is employed.
The character code 2 may be mapped to variable length coded data 4 5 representing a bitmap of the Chinese pictograph character 6 concerned. When this variable length coded data 4 is decoded (e.g. Huffman decoded, mapped to component
_ _.. 4
5 tiles and combined to form a character), then the Chinese pictograph character 6 represented may be displayed or printed.
When the pixel bitmap data representing the pictograph characters is variable length coded, the system must determine where within this variable length coded data stream the particular data 4 corresponding to a particular characte! code 6 is to be o found Figure 2 illustrates a technique for performing this mapping.
A two byte character code 2 needs to be mapped to a start position 8 within a stream of Huffman coded data 10 representing the pixel bitmaps for all of the pictograph characters within the font. The variable length coded data 4 for the particular character concerned forms a small part of the total variable length coded 5 data 10.
The first stage in the process is to use the 9 most significant bits (Bbit field)
of the character code 2 (A-bit character code) to index into Table 1. Table 1 is a 512 entry table with six bytes of data in each row. Accordingly, the 9 most significant bits 9MSB of the character code 2 can be used to directly index to a row entry within 20 Table 1.
The first two bytes from the indexed row in Table I provide an offset value TB20ff pointing to a location within a second table Table 2. The next three bytes within the row of Table 1 provide a Huffman offset value HuffOff pointing to an initial offset value within the stream of Huffman coded data 10. The final byte within 25 the index row of Table I gives an average size value AvSz for those pictograph characters having the 9 most significant bits corresponding to that row within Table 1.
The Table 2 offset value TB2Off is used to point to a starting location 14 of a region 18 correspond to the value 9MSB within Table 2. The entries within Table 2 comprise two byte rows. The first seven bits of a two byte row are used to match 30 against a corresponding 7 least significant bits 7LSB of a character code 2. The rrrimi- Q hits \xithin Thl I) rrr nroirlF cionerl frrr\r Mane Fry -A A1 1 14=. -.^. _. _.. .. . _ _ _ it,. _ _ Knowing the start point 14 in Table 2, the start point of the next region in Table 2 can also be read from the next entry in Table 1. This yields the range within Table 2 where any matching entry will be found. This range is then binary searched 3s by comparing the 7 least significant bits of the character code 2 with the most significant 7 bits of the entry in Table 2 at the midpoint of the range being searched.
The midpoint entry could match or alternatively it can be determined whether any
l' 5 matching entry will be above or below the current midpoint being tested. If the midpoint did not match, then a new midpoint of the identified region above or below will be used for the next test. This process repeats until a match is found or it is determined that no valid entry for that code is present in Table 2.
Alternatively, starting from the start point 14 in Table 2, a search is made lo down the entries in Table 2 until an entry is found for which the 7 least significant bits of the character code 2 match the most significant seven bits of the entry.
The entry in Table 2 that produces a match will be the Nth row. The entries within Table 2 may be sorted within each region corresponding to the 9 most significant bits of a character code to run in the order of the 7 least significant bits of 5 valid character codes that are possible. When the row within Table 2 is found corresponding to the character code 2, then the error value Err for that row may be read. If the Huffman coded data stream 10 is stored in a memory starting from an address HuffDataStart, then the first level of approximation for finding the position of 20 the data corresponding to the character code 2 is achieved by adding the Huffman offset value HuffOff to the start address. This will point to a position 16 starting from where the Huffman coded data for the characters having the 9 most significant bits in common with the character code 2 are stored. Table I also gives the average size value AvSz for the character codes having those 9 most significant bits. Accordingly, 2s when the search in Table 2 is made and it is determine that the Nth row in the region 18 is the one matching the 7 least significant bits of the character code, then a second level of approximation to the start address of the data 4 may be made by adding (AvSz*N) to the address 16 to obtain an address 20. The final address 8 can be obtained by adding the error value Err for the character code 2 read from T able 2 to 30 the address 20.
Figure 3 is a flow diagram illustrating the process shown in Figure 2. At step 22 a lookup operation is performed in Table I using the most significant bits of the character code 2 to index to a row within Table 1.
At step 24 a Table 2 offset value TB20ff, a Huffman offset value HuffOff and 3s an average size value AvSz are all read from the indexed row within Table 1.
5 At step 26 a search is made in Table 2 starting from the position given by TB20ff to find the entry (Nth starting from the top of the region indicated by Table 1) matching the 7 least significant bits of a character code 2.
At step 27 a test is made as to whether a valid matching entry has been found in Table 2. If a valid matching entry has not been found, then the processing aborts.
i0 At step 28 the error value Err is read from the Nth entry identified at step 26.
At step 30 an address of the Huffman coded variable length data is calculated using the start address HuffDataStart within the memory of the Huffman data stream 10 added to the values HuffOff, (AvSz*N) and Err. This calculated value points to the start location 8 of the Huffman coded data 4 for the character code 2.
5 At step 32 the Huffman coded data 4 is read from the calculated address.
At step 34 the Huffman coded data 4 is decompressed and the pictograph bitmap representation 6 of the character is rendered.
Figure 4 shows a N by M bitmap 36 representing a pictograph character 6. In t this example the bitmap is a 16 by 16 pixel bitmap. In higher resolution systems a 24 20 by 24 pixel bitmap may be used.: The pixel bitmap 36 is divided into 32 four by two pixel tiles 38. Each of i these tiles can be uniquely identified by a 8-bit code as there are 256 possible I variations in the tile.
The invention exploits the realization that some of the tile patterns are very! 2s much more common than others. Accordingly, the 8 bit codes representing the tiles 38 may be replaced by Huffman codes' with the frequently occurring tiles being given the short Huffman codes. In this way, an efficient compression of pictograph pixel bitmap font data can be made.
Figure 5 is a flow diagram illustrating the compression of a pictograph :i character. At step 40 the 16 by 16 pixel bitmap is divided into 32 tiles of 4 by 2 pixels. At step 4' each of these tiles is assigned its corresponding code value between O and 255. At step 44, the 32 values between O and 255 are Hu:ffman coded using a Huffman coding table for the whole font to generate a corresponding stream of Huffman codes. This stream of Huffman codes is a variable length coded 3- representation of the 16 by 16 pixel bitmap 36.
Figure 6 is a flow diagram illustrating the decompression of Huffman coded font data for a pixel bitmap of a pictograph character. At step 46 the stream of
7 ( s Huffman codes is decoded to generate a stream of 32 values between 0 and 255...DTD: These 8 bit values each correspond to a particular pixel pattern for a 4 by 2 pixel tile.
At step 48 these pixel patterns are looked up and combined in a preset order (e.. a horizontal raster order of eight horizontal lines each including four tiles). This assembles the 16 by 16 pixel bitmap 36 and this may be rendered (e.g. displayed or lo printed) at step 50.
Figure 7 illustrates a typical data processing system that may be used to implement the techniques described above. A common bus 52 links a central processing unit 54, a random access memory 56, a read only memory 58 and a display driver circuit 60. A display 62, such as a liquid crystal display panel, is driven by the 5 display driver circuit 60.
In operation, software stored within the read only memory 58 may be executed by the central processing unit 54 to carry out the techniques described above. The system illustrated in Figure 7 operates to perform the role of the various logic elements previously described.
20 The read only memory 58 also stores the Huffman coded font data 10, the first table Table 1 and the second table Table 2.
When the pixel bitmap 36 for the pictograph character has been decoded by the central processing unit 54, it may be sent to the display driver circuit 60 which in turn will provide the necessary signals to the display 62 to display the pictograph 25 character 6 to a user.
Claims (15)
1. Apparatus for decompressing pictograph font data for a pictograph character, uncompressed data for said pictograph character being in the form of an N by M pixel bitmap, said apparatus comprising: 0 an entropy decoder for entropy decoding a plurality of entropy codes each representing a P by Q pixel bitmap to generate a plurality P by Q pixel bitmaps for said pictograph character; and logic for combining said plurality of P by Q pixel bitmaps to generate said N by M pixel bitmap for said pictograph character.
2. Apparatus as claimed in claim 1, wherein said entropy decoder is a Huffman decoder and said entropy codes are Huffman codes each representing said P by Q pixel bitmap in accordance with a Huffman coding table for said pictograph font data, 20
3. Apparatus as claimed in any one of claims 1 and 2, wherein said P by Q pixel bitmaps are rectangular with aspect ratio not equal to 1 to 1.
4. Apparatus as claimed in claim 3, wherein said P by Q pixel bitmaps have an aspect ratio of 2 to 1.
5. Apparatus as claimed in claim 4, wherein P is 4 and Q is 2
6. Apparatus as claimed in any one of claims 1 to 5, wherein N is 24 and M is 24.
30
7 Apparatus as claimed in any one of claims I to 5, wherein N is 16 and M is 16.
8. Apparatus as claimed in any one of claims 1 to 7, wherein said entropy decoder and said logic for combining are provided by a data processing logic operating under software control.
3s
(
9 5 9. Apparatus for compressing pictograph font data for a pictograph character, uncompressed data for said pictograph character being in the form of an N by M pixel bitmap, said apparatus comprising: logic for dividing said N by M pixel bitmap for said pictograph character to generate a plurality of P by Q pixel bitmaps; and lo an entropy encoder for entropy encoding each of said plurality P by Q pixel bitmaps for said pictograph character as an entropy code to generate a plurality of entropy codes representing said pictograph character.
10. A method of decompressing pictograph font data for a pictograph character, 5 uncompressed data for said pictograph character being in the form of an N by M pixel bitmap, said method comprising the steps of: entropy decoding a plurality of entropy codes each representing a P by Q pixel bitmap to generate a plurality P by Q pixel bitmaps for said pictograph character; and combining said plurality of P by Q pixel bitmaps to generate said N by M pixel 20 bitmap for said pictograph character.
11. A method of compressing pictograph font data for a pictograph character, uncompressed data for said pictograph character being in the form of an N by M pixel bitmap, said method comprising the steps of: 2s dividing said N by M pixel bitmap for said pictograph character to generate a plurality of P by Q pixel bitmaps; and entropy encoding each of said plurality P by Q pixel bitmaps for said pictograph character as an entropy code to generate a plurality of entropy codes representing said pictograph character.
so
12. App-a+us for decompressing, substantially a s herein.before described with reference to the accompanying drawings.
13. Apparatus for compressing substantially as hereinbefUre described with 35 reference to the accompanying drawings.
! 5
14. A method of decompressing as hereinbefore described with reference to the accompanying drawings.
15. A method of compressing substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0314835A GB2388944B (en) | 1999-02-05 | 1999-02-05 | Bitmap font data storage within data processing systems |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0314835A GB2388944B (en) | 1999-02-05 | 1999-02-05 | Bitmap font data storage within data processing systems |
| GB9902664A GB2346470B (en) | 1999-02-05 | 1999-02-05 | Bitmap font data storage within data processing systems |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0314835D0 GB0314835D0 (en) | 2003-07-30 |
| GB2388944A true GB2388944A (en) | 2003-11-26 |
| GB2388944B GB2388944B (en) | 2004-03-17 |
Family
ID=10847236
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0314835A Expired - Fee Related GB2388944B (en) | 1999-02-05 | 1999-02-05 | Bitmap font data storage within data processing systems |
| GB9902664A Expired - Fee Related GB2346470B (en) | 1999-02-05 | 1999-02-05 | Bitmap font data storage within data processing systems |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9902664A Expired - Fee Related GB2346470B (en) | 1999-02-05 | 1999-02-05 | Bitmap font data storage within data processing systems |
Country Status (6)
| Country | Link |
|---|---|
| US (2) | US6236342B1 (en) |
| JP (1) | JP4361640B2 (en) |
| KR (1) | KR100622580B1 (en) |
| CN (2) | CN1145886C (en) |
| GB (2) | GB2388944B (en) |
| TW (1) | TW427079B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002059779A1 (en) * | 2001-01-25 | 2002-08-01 | Telefonaktiebolaget L M Ericsson (Publ) | Method and apparatus for optimised indexing records of static data with different lenghts |
| US20020118885A1 (en) * | 2001-02-27 | 2002-08-29 | Bernard Smeets | Font compression and retrieval |
| US20030067476A1 (en) * | 2001-10-04 | 2003-04-10 | Eastman Kodak Company | Method and system for displaying an image |
| DE10314928A1 (en) * | 2003-04-02 | 2004-11-04 | Infineon Technologies Ag | Method and program-controlled unit for bit field shifting |
| US8806103B2 (en) * | 2004-04-28 | 2014-08-12 | Hewlett-Packard Development Company, L.P. | System and method for interleaving memory |
| KR20070001765A (en) * | 2005-06-29 | 2007-01-04 | 엘에스산전 주식회사 | Memory saving character display system and display method thereof |
| JP5158934B2 (en) * | 2007-09-25 | 2013-03-06 | 京セラドキュメントソリューションズ株式会社 | Image forming apparatus |
| WO2012090584A1 (en) | 2010-12-28 | 2012-07-05 | インターナショナル・ビジネス・マシーンズ・コーポレーション | Device and method for determining search starting point |
| JP5625923B2 (en) * | 2011-01-07 | 2014-11-19 | ヤマハ株式会社 | Storage medium recording font set compressed data, method for randomly accessing font set compressed data, and decoder |
| US9626184B2 (en) * | 2013-06-28 | 2017-04-18 | Intel Corporation | Processors, methods, systems, and instructions to transcode variable length code points of unicode characters |
| US9524169B2 (en) * | 2014-09-24 | 2016-12-20 | Intel Corporation | Technologies for efficient LZ77-based data decompression |
| CN107451070B (en) * | 2016-06-01 | 2020-08-04 | 腾讯科技（深圳）有限公司 | Data processing method and server |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5544286A (en) * | 1993-01-29 | 1996-08-06 | Microsoft Corporation | Digital video data compression technique |
| EP0745946A1 (en) * | 1995-05-31 | 1996-12-04 | Sharp Kabushiki Kaisha | Data coding system and decoding circuit, in particular for the compression of Chinese character data |
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| GB2050019B (en) * | 1979-05-25 | 1982-11-10 | Loh Shiu Chang | Method of producing typographical data |
| GB2214676A (en) * | 1988-01-19 | 1989-09-06 | Benchmark Technologies | Character generation |
| JPH03145223A (en) * | 1989-10-30 | 1991-06-20 | Toshiba Corp | Variable length code demodulator |
| US5227789A (en) * | 1991-09-30 | 1993-07-13 | Eastman Kodak Company | Modified huffman encode/decode system with simplified decoding for imaging systems |
| JPH06222747A (en) * | 1992-10-08 | 1994-08-12 | Fujitsu Isotec Ltd | Font compression device and font restoration device |
| JPH0756895A (en) * | 1993-08-11 | 1995-03-03 | Canon Inc | Method for preparing bit map font data and picture forming device using the font data |
| US5512896A (en) * | 1993-11-30 | 1996-04-30 | Texas Instruments Incorporated | Huffman encoding method, circuit and system employing most significant bit change for size detection |
| US5600772A (en) * | 1994-08-17 | 1997-02-04 | Printronix, Inc. | Bit map character convertor using chain-codes for the character filling process |
| KR960014502A (en) * | 1994-10-27 | 1996-05-22 | 배순훈 | How to indicate whether the washing machine is used |
| US5732202A (en) * | 1995-02-13 | 1998-03-24 | Canon Kabushiki Kaisha | Data processing apparatus, data processing method, memory medium storing data processing program, output device, output control method and memory medium storing control program therefor |
| US5691768A (en) * | 1995-07-07 | 1997-11-25 | Lucent Technologies, Inc. | Multiple resolution, multi-stream video system using a single standard decoder |
| TW366669B (en) * | 1996-10-30 | 1999-08-11 | Matsushita Electric Ind Co Ltd | Picture encoding device and picture encoding method, picture decoding device and picture decoding method, and data recording media |
| KR19980074919A (en) * | 1997-03-27 | 1998-11-05 | 구자홍 | How to save and display bitmap fonts |
| CN1191355A (en) * | 1997-12-08 | 1998-08-26 | 王国安 | Non-loss transformation of text file data compression |
| JP4229403B2 (en) * | 1998-08-07 | 2009-02-25 | 日本放送協会 | Encoding device and decoding device for character display image |
-
1999
- 1999-02-05 GB GB0314835A patent/GB2388944B/en not_active Expired - Fee Related
- 1999-02-05 GB GB9902664A patent/GB2346470B/en not_active Expired - Fee Related
- 1999-05-06 TW TW088107408A patent/TW427079B/en not_active IP Right Cessation
- 1999-05-06 US US09/306,408 patent/US6236342B1/en not_active Expired - Fee Related
- 1999-06-25 JP JP18072299A patent/JP4361640B2/en not_active Expired - Fee Related
- 1999-07-05 CN CNB991089588A patent/CN1145886C/en not_active Expired - Fee Related
- 1999-07-05 CN CNB031284469A patent/CN1299221C/en not_active Expired - Fee Related
-
2000
- 2000-02-01 KR KR1020000004843A patent/KR100622580B1/en not_active IP Right Cessation
- 2000-09-28 US US09/671,122 patent/US6304198B1/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5544286A (en) * | 1993-01-29 | 1996-08-06 | Microsoft Corporation | Digital video data compression technique |
| EP0745946A1 (en) * | 1995-05-31 | 1996-12-04 | Sharp Kabushiki Kaisha | Data coding system and decoding circuit, in particular for the compression of Chinese character data |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000227789A (en) | 2000-08-15 |
| GB2346470B (en) | 2003-10-29 |
| GB9902664D0 (en) | 1999-03-31 |
| CN1145886C (en) | 2004-04-14 |
| GB2388944B (en) | 2004-03-17 |
| KR100622580B1 (en) | 2006-09-11 |
| CN1495617A (en) | 2004-05-12 |
| GB0314835D0 (en) | 2003-07-30 |
| GB2346470A (en) | 2000-08-09 |
| CN1263306A (en) | 2000-08-16 |
| TW427079B (en) | 2001-03-21 |
| KR20000076581A (en) | 2000-12-26 |
| JP4361640B2 (en) | 2009-11-11 |
| US6304198B1 (en) | 2001-10-16 |
| US6236342B1 (en) | 2001-05-22 |
| CN1299221C (en) | 2007-02-07 |
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