Source: http://www.google.com/patents/US6044175?dq=5636223
Timestamp: 2014-03-12 10:27:02
Document Index: 623795496

Matched Legal Cases: ['application No. 08', 'application No. 08', 'application No. 09', 'application No. 09', 'application No. 09', 'application No. 09', 'application No. 09', 'application No. 09', 'application No. 09', 'application No. 09']

Patent US6044175 - Image information encoding/decoding system - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA bit train of a plurality of continuous pixels is compressed according to a new run-length compression scheme. In this run-length compression scheme, the run information of one unit of compression includes run-length information indicating the continuous number of the same pixel data blocks, or the...http://www.google.com/patents/US6044175?utm_source=gb-gplus-sharePatent US6044175 - Image information encoding/decoding systemAdvanced Patent SearchPublication numberUS6044175 APublication typeGrantApplication numberUS 09/119,738Publication dateMar 28, 2000Filing dateJul 21, 1998Priority dateDec 28, 1994Fee statusPaidAlso published asCA2184247A1, CA2184247C, CN1146266A, CN1152554C, DE69515832D1, DE69515832T2, EP0720347A2, EP0720347A3, EP0720347B1, US5721720, US5845021, US5995667, US6011867, US6016363, US6016364, US6018594, US6021226, US6047086, US6081208, WO1996020557A1Publication number09119738, 119738, US 6044175 A, US 6044175A, US-A-6044175, US6044175 A, US6044175AInventorsShinichi Kikuchi, Tetsuya Kitamura, Hideki Mimura, Kazuhiko TairaOriginal AssigneeKabushiki Kaisha ToshibaExport CitationBiBTeX, EndNote, RefManPatent Citations (77), Non-Patent Citations (16), Referenced by (7), Classifications (36), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetImage information encoding/decoding systemUS 6044175 AAbstract A bit train of a plurality of continuous pixels is compressed according to a new run-length compression scheme. In this run-length compression scheme, the run information of one unit of compression includes run-length information indicating the continuous number of the same pixel data blocks, or the number of pixels followed, and pixel data having a two-bit configuration for discriminating three or more colors of the pixels.
What is claimed is: 1. A method of encoding image information arranged on a line, comprising:converting image information into a run-length code containing pixel information as well as a number of pixels followed which indicates a continuing number of same pixel information, and converting the run-length code into encoded data, wherein: a variable bit length of one unit of the run-length code is set in accordance with the number of pixels followed, the set variable bit length includes variable header bits which indicate a length of the continuing number of the same pixel information, variable binary bits corresponding to the continuing number of the same pixel information, and binary bits corresponding to the pixel information, and a number of the variable header bits is indicative of a number of bits following in the one unit of the run-length code representing a data length of the number of pixels followed, wherein at least one unit of the run-length code includes a specific header comprising information of a size of said at least one unit of the run-length code. 2. The method of claim 1, wherein each of said one unit of the run-length code represents a content of a group of data packets, and each of said data packets includes sub-picture data relating to said pixel information and a packet header thereof.
3. A method of decoding image information, comprising:obtaining a specific header having information of a size of at least one unit of coded data; determining said size of said at least one unit of said coded data in accordance with said information of said specific header; obtaining coded data of image information in a unit of predetermined bits, the coded data including a coding header; detecting from the obtained coded data in units of bits, a coding header being indicative of a number of continuous same bits; determining a bit length of one unit of continuous pixel information in accordance with said number indicated by said detected coding header; fetching bit information having said determined bit length; separating said fetched bit information into bits of said continuous pixel information and bits of said continuous number in accordance with said detected coding header; converting said bit information into said continuous pixel information and said continuous number thereof in a unit of the separated bits; and outputting, as decoded data, said continuous pixel information by said continuous number thereof, wherein a number of bits in said coding header is indicative of a number of following bits representing a value of said continuous number. Description
This is a division of application Ser. No. 08/806,684 filed Feb. 26, 1997 which is a division of application Ser. No. 08/577,100 filed on Dec. 22, 1995 and issued on Feb. 24, 1998 as U.S. Pat. No. 5,721,720.
(1) an encoding method of compressing/encoding recorded digital image data, such as caption data or simple animated cartoon data;
(10) an electronic mail system for exchanging various pieces of information, which are compressed/encoded by the encoding method, by radio or via network lines (e.g., internet lines).
As methods of compressing and recording or communicating image data, such as caption data, the following conventional methods are known.
In the first method, a character font ROM-corresponding to each character code set must be prepared in the image playing back apparatus. A character code which does not correspond to any one of the character font ROMs cannot be played back. For this reason, in order to allow the image playing back apparatus to handle a plurality of languages, a character font ROM is required for each language.
Consider a pixel data line like aaaabbbbbbbcccccdd". According to the run-length compression method, this data line is converted into data (run-length compressed code) like "a4, b7, c5, d2" consisting of pieces of pixel information (a, b, c, and d) and the numbers of pixels followed (4, 7, 5, and 2) indicating the numbers of pieces of pixel information.
For this reason, MH codings in a multilingual system handling various language s lead to great increases in the costs of both the encoder and the de coder.
In performing arithmetic codings, first, data is read, and the frequency of use of each data is checked. Codes having small numbers of bits are then assigned to the data in the order of de creasing frequencies of use so as to form a code table. The code table formed in this manner is recorded (or transmitted) as data. Thereafter, the data is encode d o n the basis of this code table.
In arithmetic codings, although a code table must be recorded or transmitted, data can be formed by using a code table optimal for the contents of a file to be recorded or transmitted. I n addition, in arithmetic codings, complicated code tables are not required in both an encoder and a decoder, unlike in MH codings.
In arithmetic codings, however, because a code table is formed in encoding data, the data must be read twice, and decoding processing is complicated.
U.S. Pat. No. 4,811,113 discloses an image encoding method that is different from the above two methods. In this method, a flag bit representing th e number of bits as a code data length is prepared before a run-length code, and encoding and decoding are performed while an integer multiple of the value of the flag bit is regarded as a code data length.
In this method, since a data length is calculated from a flag bit, a large code table is not required, unlike in MH codings. However, the internal circuit arrangement of a decoder tends to be complicated because of the hardware for calculating a code data length.
SUMMARY OF THE INVENTION It is the first object of the present invention to provide an image information encoding method which can eliminate the drawback (i.e., the necessity of using large code tables) of MH codings, the drawback (i.e., the necessity to read data twice) of arithmetic codings, and the drawback (i.e., the inability to compress multi-color image data) of the flag-bit-attached run-length coding method (U.S. Pat. No. 4,811,113) at a practical level.
It is the tenth object of the present invention to provide an electronic mail system for exchanging various pieces of information, which are compressed/encoded by the encoding method according to the first object, by radio or via network lines (e.g., internet lines).
To achieve the above-mentioned first object, according to an encoding method of the present invention, an information integral body (e.g., PXD in FIGS. 9A and 9B, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is processed so that a data block, containing the same continuous pixel data, is compressed as one unit of compression (e.g., any of CUO1 to CU04 in FIGS. 9A and 9B). The encoding method comprises the steps of:
a compression data generating step (e.g., ST806 in FIG. 13, or ST908 to ST914 in FIG. 14) for generating a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit.
To achieve the above-mentioned second object, according to a decoding method of the present invention, a bit train of one unit of a compressed data block, obtained by compressing the same continuous pixel data as one unit of compression, is expanded (e.g., ST1005 in FIG. 15), wherein the compressed data block corresponds to at least part of an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10) formed by a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), and the compressed data block includes a coding header indicating data of a number of pixels followed, which number data corresponds to the number of the same continuous pixel data, or includes a coding header indicating the number data of pixels followed as well as the same continuous pixel data thereof. The decoding method comprises the steps of:
a coding header detecting step (e.g., ST1101 to ST1109 in FIG. 16) for detecting the coding header from the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit contained in the information integral body (PXD/SPD);
a continuous pixel number detecting step (e.g., ST1110 to ST1113 in FIG. 16) for detecting the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D, or data length of zero as in the case of rule 5 in FIG. 5E; the zero data length will not affect on a later subtraction), from the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit, in accordance with a content of the coding header (e.g., data length of any of 0-bit to 6-bit at rules 1 to 4 in FIGS. 5A-5D; the data length of 0-bit as in the case of rule 1 will not affect on a later subtraction) detected by the coding header detecting step (ST1101 to ST1109);
a pixel data determining step (e.g., ST1114 in FIG. 16) for determining a content (e.g., any of "00", "01", "10", "11") of the pixel data in an uncompressed data block (e.g., any of CU01 to CU04 in FIG. 9A) of the one compression unit, in accordance with a remainder (e.g., 2-bit of the pixel data at rules 1 to 4 in FIGS. 5A-D) of the data block (e.g., any of CU01* to CU04* in FIG. 9) of the one compression unit, from which removed are the coding header (e.g., any of 0-bit to 6-bit) detected by the coding header detecting step (ST1101 to ST1109 in FIG. 16) and the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) detected by the continuous pixel number detecting step (ST1110 to ST1113 in FIG. 16); and
a pixel pattern restoration step (e.g., ST1115 to ST1118 in FIG. 16) for arranging bit data of the content determined by the pixel data determining step (ST1114 in FIG. 16), by a number indicated by the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) detected by the continuous pixel number detecting step (ST1110 to ST1113 in FIG. 16), so as to restore a pattern of uncompressed pixel data of the one compression unit.
To achieve the above-mentioned third object, according to a system of the present invention, an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is processed so that a data block, containing the same continuous pixel data, is compressed (e.g., ST806 in FIG. 13) as one unit of compression (e.g., any of CU01 to CU04 in FIG. 9A), and a bit train of the compressed data block is then expanded (e.g., ST1005 in FIG. 15). The system is constituted by a combination of:
a step (e.g., ST806 in FIG. 13) for generating a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit, and
(b) a decoding-processing including:
a coding header detecting step (e.g., ST1101 to ST1109 in FIG. 16) for detecting the coding header from the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit generated by the generating step of the encoding processing, wherein the coding header indicates the number of pixels followed (e.g., 2-bit to 8-bit), or indicates a group of the number of pixels followed (e.g., 2-bit to 8-bit) and the same pixel data (e.g., 2-bit);
a continuous pixel number detecting step (e.g., ST1110 to ST1113 in FIG. 16) for detecting the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) from the data block (e.g., any of CU01* to CU04* in FIG. 9B), after the coding header is detected;
a pixel data determining step (e.g., ST1114 in FIG. 16) for determining a content (e.g., any of "00", "01", "10", "11") of the pixel data in an uncompressed data block (e.g., any of CU01 to CU04 in FIG. 9B) of the one compression unit, in accordance with a remainder (e.g., 2-bit of the pixel data at rules 1 to 4 in FIGS. 5A-5D) of the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit, from which removed are the coding header (e.g., any of 0-bit to 6-bit; the data length of 0-bit of the header will not affect on A later subtraction) detected by the coding header detecting step (ST1101 to ST1109 in FIG. 16) and the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) detected by the continuous pixel number detecting step (ST1110 to ST1113 in FIG. 16); and
To achieve the above-mentioned fourth object, according to an information recording medium of the present invention, an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is recorded so that a data block, containing the same continuous pixel data, is compressed as one unit of compression (e.g., any of CU01 to CU04 in FIG. 9A). The information recording medium stores a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) which comprises a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit.
To achieve the above-mentioned fifth object, according to an encoding apparatus (such as an integrated circuit device in which the encoding method of the first object is used) of the present invention, an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is processed so that a data block, containing the same continuous pixel data, is compressed as one unit of compression (e.g., any of CU01 to CU04 in FIG. 9A). The encoding apparatus comprises:
a compression data generating means (e.g., ST806 in FIG. 13, or ST908 to ST914 in FIG. 14) for generating a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5B) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit.
To achieve the above-mentioned sixth object, according to a decoding apparatus (such as an integrated circuit device in which the decoding method of the second object is used) of the present invention, a bit train of one unit of a compressed data block, obtained by compressing the same continuous pixel data as one unit of compression, is expanded (e.g., ST1005 in FIG. 15), wherein the compressed data block corresponds to at least part of an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10) formed by a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), and the compressed data block includes a coding header indicating data of a number of pixels followed, which number data corresponds to the number of the same continuous pixel data, or includes a coding header indicating the number data of pixels followed as well as the same continuous pixel data thereof. The decoding apparatus comprises:
a coding header detecting means (e.g., ST1101 to ST1109 in FIG. 16) for detecting the coding header from the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit contained in the information integral body (PXD/SPD);
a continuous pixel number detecting means (e.g., ST1110 to ST1113 in FIG. 16) for detecting the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D), from the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit, in accordance with a content of the coding header (e.g., data length of any of 0-bit to 6-bit at rules 1 to 4 in FIGS. 5A-5D) detected by the coding header detecting means (ST1101 to ST1109);
a pixel data determining means (e.g., ST1114 in FIG. 16) for determining a content (e.g., any of "00", "01", "10", "11") of the pixel data in an uncompressed data block (e.g., any of CU01 to CU04 in FIG. 9A) of the one compression unit, in accordance with a remainder (e.g., 2-bit of the pixel data at rules 1 to 4 in FIGS. 5A-5D) of the data block (e.g., any of CU01* to CU04* in FIG. 9B) of the one compression unit, from which removed are the coding header (e.g., any of 0-bit to 6-bit) detected by the coding header detecting means (ST1101 to ST1109 in FIG. 16) and the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) detected by the continuous pixel number detecting means (ST1110 to ST1113 in FIG. 16); and
a pixel pattern restoration means (e.g., ST1115 to ST118 in FIG. 16) for arranging bit data of the content determined by the pixel data determining means (ST1114 in FIG. 16), by a number indicated by the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) detected by the continuous pixel number detecting means (ST1110 to ST1113 in FIG. 16), so as to restore a pattern of uncompressed pixel data of the one compression unit.
To achieve the above-mentioned seventh object, according to a recording apparatus of the present invention, an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is processed so that a data block, containing the same continuous pixel data, is compressed as one unit of compression (e.g., any of CU01 to CU04 in FIG. 9A). The recording apparatus comprises:
a compression data generating means (e.g., 200 in FIG. 24; ST806 in FIG. 13, or ST908 to ST914 in FIG. 14) for generating a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit; and
a recording means (e.g., 702 to 704 in FIG. 24) for recording on a prescribed recording medium (e.g., 0D in FIG. 24) the compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) generated by the compression data generating means (200).
To achieve the above-mentioned eighth object, according to a playing back apparatus of the present invention, a bit train of one unit of a compressed data block, obtained by compressing the same continuous pixel data as one unit of compression, is played back from a recording medium (e.g., 0D) and is expanded (e.g., ST1005 in FIG. 15), wherein the compressed data block corresponds to at least part of an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10) formed by a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), and the compressed data block includes a coding header indicating data of a number of pixels followed, which number data corresponds to the number of the same continuous pixel data, or includes a coding header indicating the number data of pixels followed as well as the same continuous pixel data thereof. The playing back apparatus comprises:
a pixel pattern restoration means (e.g., ST1115 to ST1118 in FIG. 16) for arranging bit data of the content determined by the pixel data determining means (ST1114 in FIG. 16), by a number indicated by the number data of the pixels followed (e.g., any of 2-bit to 8-bit in FIGS. 5A-5D) detected by the continuous pixel number detecting means (ST1110 to ST1113 in FIG. 16), so as to restore a pattern of uncompressed pixel data of the one compression unit.
To achieve the above-mentioned ninth object, according to a broadcasting system of the present invention, an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is processed so that a data block, containing the same continuous pixel data, is compressed as one unit of compression (e.g., any of CU01 to CU04 in FIG. 9A). The broadcasting system comprises:
an encoder (e.g., 200 in FIG. 10) for generating a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit; and
a broadcasting means (e.g., 210 to 212 in FIG. 10) for outputting, by means of a radio wave or signal cable, the compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) generated by the encoder (200).
a digital signal generator means (e.g., 300 in FIG. 22) for generating a digital signal of a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit; and
To achieve the above-mentioned tenth object, according to an electric mailing system of the present invention, an information integral body (e.g., PXD in FIG. 9A, or SPD in FIG. 10), formed of a plurality of pixel data each defined by a predetermined number of bits (e.g., 2-bit), is processed so that a data block, containing the same continuous pixel data, is compressed as one unit of compression (e.g., any of CU01 to CU04 in FIG. 9A). The electric mailing system comprises:
a compressed data generating means (e.g., 5001 to 5031 in FIG. 23) for generating a compressed unit data block (e.g., CU01* to CU04* in FIG. 9B) in accordance with a coding header (e.g., 0-bit to 6-bit of rules 1 to 4 in FIGS. 5A-5D) corresponding to a continuing number (e.g., any of 1 to 255) of the same pixel data in the data block of the one compression unit, with a number of pixels followed (e.g., 2-bit to 8-bit) indicating the continuing number (1-255) of the same pixel data, and with data (e.g., 2-bit) representing the same pixel data in the data block of the one compression unit;
a transmitter means (e.g., 5031, 600 in FIG. 23) for transmitting a signal containing the compressed unit data block (CU01* to CU04* in FIG. 9B) generated by the compressed data generating means (5001 to 5031 in FIG. 23);
&lt;Rule 1&gt; For Continuous 1 to 3 Identical Pixel Data:
If the number of pixels followed (e.g., "11") is one, then PXD=01
If the number of pixels followed (e.g., "10") is two, then PXD=10
If the number of pixels followed (e.g., "00") is three, then PXD=11
&lt;Rule 2&gt; For Continuous 4 to 15 Identical Pixel Data:
If the number of pixels followed (e.g., "01") five, then PXD=00
&lt;Rule 3&gt; For Continuous 16 to 63 Identical Pixel Data
If the number of pixels followed (e.g., "10") is 16, then PXD=0000
If the number of pixels followed (e.g., "11") is 46, then PXD=0000
&lt;Rule 4&gt; For Continuous 64 to 255 Identical Pixel Data:
If the number of pixels followed (e.g., "01") is 255, then PXD=00000
&lt;Rule 5&gt; For Continuous Identical Pixel Data Up to the End of Line of Pixel Data String to be Run-Length Coded:
If identical pixels (e.g., "00") continues to the end of a line, then PXD=00000000000000
If identical pixels (e.g., "11") continues to the end of a line, then PXD=00000000000000
&lt;Rule 6&gt; For Non-Byte-Aligned State at the End of Line:
[0/1 data string=(integer multiple of 8)-4 bits]
FIGS. 1A-1C illustrate the structure of data recorded on an optical disk as an information holding medium to which the present invention is applied;
FIGS. 2A-2B illustrate the logical structure of data to be recorded on the optical disk in FIG. 1;
FIGS. 4A-4B illustrate the contents of the sub-picture data of the sub-picture pack in FIG. 3, to which an encoding method according to an embodiment of the present invention is applied;
FIGS. 5A-5F explain compression rules 1 to 6 used in an encoding method according to an embodiment of the present invention in a case wherein image data constituting the sub-picture data portion in FIG. 4 consists of a plurality of bits (2 bits in this case);
FIGS. 6A-6E explain compression rules 11 to 15 used in an encoding method according to another embodiment of the present invention in a case wherein image data constituting the sub-picture data portion in FIG. 4 consists of 1 bit;
FIGS. 7A-7C provide a detailed example of how the pixel data of each line is encoded (i.e., run-length compressed) in a case wherein pixel data constituting the sub-picture data portion in FIG. 4 consists of, e.g., first to ninth lines, 2-bit pixels (i.e., a maximum of four types) are arranged on each line, and character patterns "A" and "B" are expressed by the 2-bit pixels on the respective lines;
FIGS. 8A-8C explain two examples (i.e., non-interlaced display and interlaced display) of how the character pattern "A" of the pixel data (i.e., sub-picture data) encoded as shown in FIGS. 7A-7C is decoded;
FIGS. 9A-9B explain compression rules 1 to 6, in detail, which are used in an encoding method according to an embodiment of the present invention in a case wherein image data constituting the sub-picture data in FIG. 4 consists of 2 bits;
FIG. 13 is a flow chart for explaining the operations of software for the execution of image encoding (run-length compression) according to an embodiment of the present invention, which is executed, for example, by an encoder (200) in FIG. 10;
FIG. 22 is a block diagram for explaining a case wherein the compressed data, reproduced from a high-density optical disk having image information encoded according to the present invention, is directly aired or output to a cable, and the aired or cable-distributed compressed data is decoded at the user side or at the subscriber side;
FIG. 24 shows a schematic illustration of a record/playback apparatus for recording on an optical disk OD the image information encoded according to the present invention, and for playing back the recorded information to decode it according to the present invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Encoding and decoding methods according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In order to avoid a repetitive description, the same reference numerals denote parts having the same functions throughout the drawings.
FIGS. 1A to 27 are views for explaining an image information encoding/decoding system according to an embodiment of the present invention.
FIGS. 1A-1C schematically show the structure of data recorded on double-sided optical disk OD 1 as an information holding medium to which the present invention can be applied.
Optical disk OD 1 is a double-sided optical disk. Each surface of this optical disk has a storage capacity of about 5 Gbytes. Many recording tracks 2 are arranged between the lead-in area 3 on the inner peripheral side of the disk and the lead-out area 4 on the outer peripheral side of the disk. Each track is constituted by many logical sectors 5. Various pieces of information (compressed digital data) are stored in the respective sectors 5.
FIGS. 2A-2B show the logical structure of data to be recorded on the optical disk in FIG. 1. More specifically, a system area in which system data used by disk OD is stored, a volume management information area, and a plurality of file areas are formed in the aggregate of logical sectors in FIG. 1.
Of the plurality of file areas, for example, file 1 which is illustrated in detail in FIG. 2B contains main picture information ("VIDEO" in FIG. 2), sub-picture information ("SUB-PICTURE" in FIG. 2) having contents supplementary to the main picture information, audio information ("AUDIO" in FIG. 2), playback information ("PLAYBACK INFO." in FIG. 2), and the like.
FIGS. 4A-4B show the contents of sub-picture unit header 31 in one unit of run-length compressed data 30 in FIG. 3. The data of a sub-picture (e.g., subtitles corresponding to a scene in a movie) to be recorded/transmitted (communicated) together with a main picture (e.g., a picture of the movie) will be described below.
As will be seen from FIG. 4B, recorded in sub-picture unit header 31 are: start address SPDDADR of sub-picture pixel data (display data); end address SPEDADR of pixel data 32; data SPDSIZE of the display-start position and display area (width and height) of pixel data 32 with respect to a TV display screen; background color SPCHI designated by the system; sub-picture color SPCINFO designated by the system; pallet color number SPADJINFO of an emphasizing color designated by the system; modification information SPMOD of sub-picture pixel data 32; mixing ratio SPCONT of sub-picture (SP) to main-picture (MP); start-timing (corresponding to the frame number of MP) SPDST of the sub-picture; and start addresses SPLine1 to SPLineN of decode data of respective lines.
More specifically, as indicated in FIG. 4B, various parameters (e.g., SPDDADR) having the following contents are recorded on sub-picture unit header 31:
(10) information (SPlin1) indicating the start address (an address relative to the beginning of the sub-picture unit header) of the encoded data on the first line of the sub-picture; and
(11) information (SPlinN)-indicating the start address (an address relative to the beginning of the sub-picture unit header) of the encoded data on the Nth line of he sub-picture.
Note that information SPCONT indicating the mixing ration of the sub-picture to the main picture indicates the mixing ratio of the sub-picture with (system set value)/255, and the mixing ratio of the main picture with (255-set value)/255.
Sub-picture unit header 31 includes the start address (SPLine 1 to SPLine N) of data to be decoded on every lines. For this reason, scrolling of only the sub-picture on the display screen can be realized by changing the designation of a decoding start line in accordance with an instruction from a microcomputer (MPU or CPU) on the decoding side. (How the scrolling is performed will be described later with reference to FIG. 21).
The data length (variable length) of the pixel data (run-length data) 32 of sub-picture shown in FIG. 3 or 4A is determined depending on whether run-length compression rules 1 to 6 in FIGS. 5A-5F or run-length compression rules 11 to 15 in FIGS. 6A-6E are used.
Rules 1 to 6 in FIGS. 5A-5F are used when pixel data to be compressed has a multi-bit configuration (2 bits in this-case). Rules 11 to 15 in FIGS. 6A-6E are used when pixel data to be compressed has a 1-bit configuration.
Whether run-length compression rules 1 to 6 or 11 to 15 are to be used can be determined by the contents (e.g., a bit width flag) of parameter SPMOD (see a portion near the middle of the table shown at the lower portion in FIG. 4) in sub-picture unit header 31. If, for example, the bit width flag of parameter SPMOD is "1", the pixel data to be run-length compressed is 2-bit data, and hence rules 1 to 6 in FIGS. 5A-5F are used. If the bit width flag of parameter SPMOD is "0", the pixel data to be run-length compressed is 1-bit data, and hence rules 11 to 15 in FIGS. 6A-6E are used.
Assume that four groups A, B, C, and D of compression rules are provided respectively for four kinds of the bit-configuration of pixel data, when this pixel data can optionally have the bit-configuration of either of 1-bit, 2-bit, 3-bit, and 4-bit. Under this assumption, when parameter SPMOD is constituted by 2-bit flag, the 1-bit pixel data using rule group A can be designated by the 2-bit flag of "00". In similar manner, the 2-bit pixel data using rule group B can be designated by the 2-bit flag of "01", the 3-bit pixel data using rule group C can be designated by the 2-bit flag of "10", and the 4-bit pixel data using rule group D can be designated by the 2-bit flag of "11". In this case, rules 11 to 15 of FIGS. 6A-6E can be used for the compression rules of group A, and rules 1 to 6 of FIGS. 5A-5F can be used for the compression rules of group B. When the contents of coding headers and the bit-configuration of pixel data, as well as the number of rules, are properly modified, the compression rules of groups C and D will be derived from rules 1 to 6 of FIGS. 5A-5F.
FIGS. 5A to 5F explain the run-length compression rules 1 to 6 which are used in an encoding method according to an embodiment of the present invention, wherein pixel data constituting sub-picture pixel data (run-length data) 32 in FIG. 4 consists of a plurality of bits (2 bits in this case).
FIGS. 9A-9B explain the compression rules 1 to 6, in detail, in a case wherein pixel data constituting sub-picture pixel data (run-length data) 32 in FIG. 4 consists of 2 bits.
According to rule 1 in FIG. 5A, when 1 to 3 identical pixels continue in sequence, one encoded (run-length compressed) data unit is constituted by 4 bits. In this case, the first 2 bits represent the number of pixels followed, and the next 2 bits represent pixel data (pixel color information or the like).
For example, first compression data unit CU01 of picture data PXD before compressed, which is indicated in FIG. 9A, contains 2 2-bit pixel data d0, d1=(0000)b (b indicates binary data). In this case, 2 identical 2-bit pixel data (00)b continue in sequence.
In this case, as indicated in FIG. 9B, 2-bit display (10)b representing the number of pixels followed "2" is coupled to contents (00)b of the pixel data to form d0, d1=(1000)b, which is compressed data unit CU01* of picture data PXD.
In other words, (0000)b of data unit CU01 is converted into (1000)b of data unit CU01* according to rule 1. In this case, bit length compression is not practically realized. However, for example, 3 continuous identical pixels (00)b, i.e., CU01=(000000)b, are compressed into CU01*=(1100)b. That is, the pixel data can be compressed by 2 bits.
According to rule 2 in FIG. 5B, when 4 to 15 identical pixels continue, one encoded data unit is constituted by 8 bits. In this case, the first 2 bits represent a coding header indicating that encoding is performed according to rule 2, the subsequent 4 bits represent the number of identical pixels followed in sequence, and the next 2 bits represent the pixel data.
For example, second compression data unit CU02 of picture data PXD before being compressed, which is indicated in FIG. 9A, contains 5 2-bit pixel data d2, d3, d4, d5, d6=(010101010)b. In this case, 5 identical 2-bit pixel data (01)b continue in sequence.
In this case, as indicated in FIG. 9B, coding header (00)b, 4-bit display (0101)b representing the number of pixels followed, i.e., "5", and contents (00)b of the pixel data are coupled to each other to form d2-d6=(00011010)b, which is the compressed data unit CU02* of picture data PXD.
In other words, (010101001)b (10-bit length) of data unit CU02 is converted into (00010101)b (8-bit length) of data unit CU02* according to rule 2. In this case, the 10-bit data is compressed into the 8-bit data, i.e., the substantial bit length compression amount corresponds to only 2 bits. If, however, the number of pixels followed is 15 (which corresponds to a 30-bit length because 15 "01"s of CU02 continue in sequence), the data is compressed into 8-bit data (CU02*=00111101). That is, 30-bit data can be compressed by 22 bits. The bit compressing effect based on rule 2 is therefore larger than that based on rule 1. In order to cope with run-length compression of a fine image with high resolution, rule 1 is also required.
According to rule 3 in FIG. 5C, when 16 to 63 identical pixels continue, one encoded data unit is constituted by 12 bits. In this case, the first 4 bits represent a coding header indicating that encoding is performed according to rule 3, the subsequent 6 bits represent the number of identical pixels followed in sequence, and the next 2 bits represent pixel data.
For example, third compression data unit CU03 of picture data PXD before being compressed, which is indicated in FIG. 9A, contains 16 2-bit pixel data d7 to d22=(101010 . . . 1010)b. In this case, 16 identical 2-bit pixel data (10)b continue.
In this case, as indicated in FIG. 9B, coding header (0000)b, 6-bit display (010000)b representing the number of pixels followed "16", and contents (10)b of the pixel data are coupled to each other to form d7 to d22=(00000100000)b, which is the compressed data unit CU03* of picture data PXD.
In other words, (101010 . . . 1010)b (32-bit length) of data unit CU03 is converted into (000001000010)b (12-bit length) of compressed data unit CU03* according to rule 3. In this case, the 32-bit data is compressed into the 12-bit data, i.e., the substantial bit length compression amount corresponds to 20 bits. If, however, the number of pixels followed is 63 (which corresponds to a 126-bit length because 63 "10"s of CU03 continue), the data is compressed into 12-bit data (CU03*=000011111110). That is, 126-bit data can be compressed by 114 bits. The bit compressing effect based on rule 3 is therefore larger than that based on rule 2.
According to rule 4 in FIG. 5D, when 64 to 255 identical pixels continue, one encoded data unit is constituted by 16 bits. In this case, the first 6 bits represent a coding header indicating that encoding is performed according to rule 4, the subsequent 8 bits represent the number of identical pixels followed, and the next 2 bits represent pixel data.
For example, fourth compression data unit CU04 of picture data PXD before compressed, which is indicated in FIG. 9A, contains 69 2-bit pixel data d23 to d91=(111111 . . . 1111)b. In this case, 69 identical 2-bit pixel data (11)b continue in sequence.
In this case, as indicated by the lower portion in FIG. 9, coding header (000000)b, 8-bit display (00110010)b representing the number of identical pixels followed "69", and contents (11)b of the pixel data are coupled to each other to form d23 to d91=(0000000011001011)b, which is compressed data unit CU04* of picture data PXD .
In other words, (111111 . . . 1111)b (138-bit length) of data unit CU04 is converted into (0000000011001011)b (16-bit length) of compressed data unit CU04* according to rule 4. In this case, the 138-bit data is compressed into the 16-bit data, i.e., the substantial bit length compression amount corresponds to 122 bits. If, however, the number of pixels followed is 255 (which corresponds to a 510-bit length because 255 "11"s of CU04 continue), the data is compressed into 16-bit data (CU04*=0000001111111111). That is, 510-bit data can be compressed by 494 bits. The bit compressing effect based on rule 4 is therefore larger than that based on rule 3.
According to rule 5 in FIG. 5E, when identical pixels continue from a switching point of a data unit of encoding to the end of a line, one encoded data unit is constituted by 16 bits. In this case, the first 14 bits represent a coding header indicating that encoding is performed according to rule 5, and the next 2 bits represent the pixel data.
For example, fourth compression data unit CU05 of picture data PXD before being compressed, which is indicated in FIG. 9A, contains one or more 2-bit pixel data d92 to dn=(000000 . . . 0000)b. In this case, a finite number of identical 2-bit pixel data (00)b continue. According to rule 5, however, the number of pixels followed may be 1 or more.
In this case, as indicated in FIG. 9B, coding header (00000000000000)b is coupled to the contents (00)b of the pixel data to form d92 to dn=(0000000000000000)b, which is a compressed data unit CU05* of picture data PXD .
In other words, (000000 . . . 0000)b (unspecified bit length) of data unit CU05 is converted into (0000000000000000)b (16-bit length) of data unit CU05* according to rule 5. According to rule 5, if the number of identical and sequential pixels up to the end of a line is 16 or more, a compressing effect can be obtained.
According to rule 6 in FIG. 5F, if the length of 1-line compressed data PXD is not an integer multiple of 8 bits (i.e., not byte-aligned) at the end of a pixel line on which data to be encoded are arranged, 4-bit dummy data is added to the 1-line compressed data to make 1-line compressed data PXD coincide with a byte unit (i.e., for byte-aligning).
For example, the total bit length of data units CU01* to CU05* of picture data PXD after being compressed, which is indicated by the lower portion in FIG. 9, is always an integer multiple of 4 bits. However, this length is not always an integer multiple of 8 bits.
If, for example, the total bit length of data units CU01* to CU05* is 1020, and 4 bits are required for byte-aligning. Therefore, 4-bit dummy data CU06*=(0000)b is added to the end of the 1020-bit data to output data units CU01* to CU06* as byte-aligned 1024-bit data.
FIGS. 6A-6E explain the run-length compression rules 11 to 15 which are used in an encoding method according to another embodiment of the present invention, wherein pixel data constituting sub-picture pixel data (run-length data) 32 in FIG. 4 consists of one bit.
According to rule 11 in FIG. 6A, when 1 to 7 identical pixels continue, one encoded (run-length compressed) data unit is constituted by 4 bits. In this case, the first 3 bits represent the number of pixels followed, and the next 1 bit represents pixel data (information such as a pixel type). If, for example, 1-bit pixel data "0", it indicates a background pixel of a sub-picture. If this data is "1", it indicates a pattern pixel of the sub-picture.
According to rule 12 in FIG. 6B, when 8 to 15 identical pixels continue, one encoded data unit is constituted by 8 bits. In this case, the first 3 bits represent a coding header (e.g., 0000 indicating that encoding is based on rule 12, the subsequent 4 bits represent the number of pixels followed, and the next 1 bit represents pixel data.
According to rule 13 in FIG. 6C, when 16 to 127 identical pixels continue, one encoded data unit is constituted by 12 bits. In this case, the first 4 bits represent a coding header (e.g., 0000) indicating that encoding is based on rule 13, the subsequent 7 bits represent the number of pixels followed, and the next 1 bit represents pixel data.
According to rule 14 in FIG. 6D, when identical pixels continue from a switching point of a data unit of encoding to the end of a line, one encoded data unit is constituted by 8 bits. In this case, the first 7 bits represent a coding header (e.g., 0000000) indicating that encoding is performed according to rule 14, and the next 1 bit represents pixel data.
According to rule 15 in FIG. 6E, if the length of 1-line compressed data PXD is not an integer multiple of 8 bits (i.e., not byte-aligned) at the end of a pixel line on which data to be encoded are arranged, 4-bit dummy data is added to the 1-line compressed data to make 1-line compressed data PXD coincide with a byte unit (i.e., for byte-aligning).
An image encoding method (an encoding method using run-length coding) will be described in detail next with reference to FIGS. 7A-7C.
FIG. 7A shows a case wherein pixel data constituting sub-picture pixel data (run-length data) 32 in FIG. 4 is constituted by the first to ninth lines, 2-bit pixels (having a maximum of four types of contents) are arranged on each line, and character patterns "A" and "B" are expressed by the 2-bit pixels on the respective lines. The manner of encoding (run-length compressing) the pixel data on each line will be described in detail below.
As indicated in FIG. 7A, an image as a source is constituted by three types (a maximum of four types) of pixel data. That is, 2-bit image data (00)b represents the pixel color of the background of the sub-picture; 2-bit image data (00)b, the pixel color of characters "A" and "B" in the sub-picture; and 2-bit image data (10)b, an emphasizing pixel color with respect to sub-picture characters "A" and "B".
This encoder can be constituted by a microcomputer (MPU or CPU) in which software for executing run-length compression based on rules 1 to 6 described with reference to FIGS. 5A-5F runs. This encoder software will be described later with reference to the flow charts in FIGS. 13 and 14.
In the case shown in FIG. 7A, a source image is assumed to have three color pixels. More specifically, in picture data (the sequential bit string of character patterns "A" and "B") to be encoded, background color pixel ".circle-solid." is represented by 2-bit pixel data (00)b, character color pixel "#" is represented by 2-bit pixel data (01)b, and emphasizing color pixel "∘" is represented by 2-bit pixel data (10)b. The bit count (=2) of pixel data (e.g., 00 or 01) is also called a pixel width.
For the sake of simplicity, in the case shown in FIG. 7A, the display width of picture data (sub-picture data) to be encoded is set to be 16 pixels, and the number of scanning lines (display height) is set to be 9 lines.
Consider the first line in FIG. 7A. Three continuous pixels ".circle-solid..circle-solid..circle-solid." are converted into (.circle-solid.*3); subsequent 1 pixel "0", (0*1); subsequent 1 pixel "#", (#*1); subsequent 1 pixel "∘", (∘*1); subsequent continuous 3 pixels ".circle-solid..circle-solid..circle-solid.", (.circle-solid.*3); subsequent 1 pixel "∘", (∘*1); subsequent continuous 4 pixels "####", (#*4); subsequent 1 pixel "∘", (!{*1); and last 1 pixel ".circle-solid.", (.circle-solid.*1).
As a result, as indicated in FIG. 7B, the run-length data (before compressed) on the first line becomes ".circle-solid.*3/∘*1/#*1/∘*1/.circle-solid.*3/.smallcircle.*1/#*4/∘* 1/.circle-solid.*1". This data is constituted by a combination of image information such as a character color pixel, and the number of pixels followed which represents a continuation count.
Similarly, the pixel data strings on the second to ninth lines indicated in FIG. 7A become the run-length data strings on the second to ninth lines indicated in FIG. 7B.
Consider the data on the first line. Since 3 background color pixels ".circle-solid..circle-solid..circle-solid." continue from the start of the line, compression rule 1 in FIG. 5A is used. As a result, first three pixels ".circle-solid..circle-solid..circle-solid.", i.e., (.circle-solid.*3), on the first line are encoded into (1100), which is a combination of 2 bits (11) representing "3" and (00) representing background color pixel ".circle-solid.".
Since the next data on the first line is 1 pixel "∘", rule 1 is used. As a result, next pixel "∘", i.e., (∘*1), on the first line is encoded into (0110), which is a combination of 2 bits (01) representing "1" and (10) representing emphasizing color pixel " ".
Since the next data is 1 pixel "#'", rule 1 is used. As a result, next pixel "#", i.e., (#*1), on the first line is encoded into (0101), which is a combination of 2 bits (01) representing "1" and (01) representing character color pixel "#" (the portions corresponding to pixels "### . . . " are enclosed with the broken lines in FIGS. 7B-7C).
Similarly, (∘*1) is encoded into (0110); (.circle-solid.*3), (1100); and (∘*1), (0110).
Since the subsequent data on the first line are 4 pixels "###", compression rule 2 in FIG. 5B is used. As a result, pixels "####", i.e., (#*4), on the first line are encoded into (00010001), which is a combination of 2-bit header (00) representing that rule 2 is used, 4 bits (0100) representing the number of pixels followed "4", and (01) representing character color pixel "#" (the portions corresponding to "#" are enclosed with the broken lines in FIGS. 7B-7C).
Since the subsequent data on the first line is 1 pixel "∘', rule 1 is used. As a result, pixel "∘", i.e., (∘*1), is encoded into (0110), which is a combination of 2 bits (01) representing "1" and (10) representing emphasizing color pixel "∘".
Since the last data on the first line is 1 "∘", rule 1 is used. As a result, pixel ".circle-solid.", i.e., (.circle-solid.*1), is encoded into (0100), which is a combination of 2 bits (01) representing "1" and (00) representing background color pixel ".circle-solid.".
In the above manner, run-length data ".circle-solid.*3/∘*1/#*1/∘*1.circle-solid.*3/.smallcircle.*1/#*4/∘*1/.circle-solid.*1" (before compressed) on the first line is run-length compressed into (1100) (0110) (0101) (0110) (1100) (0110) (00010001) (0110) (0100), thereby completing the encoding of the first line.
In the same manner as described above, encoding proceeds up to the eighth line. All the data on the ninth line are identical background color pixels ".circle-solid..circle-solid..circle-solid. . . . " In this case, compression rule 5 in FIG. 5E is used. As a result, run-length data ".circle-solid.*16" (before compressed) on the ninth line is encoded into 16-bit data (0000000000000000), which is a combination of 14-bit header (00000000000000) representing that identical background color pixels ".circle-solid..circle-solid..circle-solid. . . . " continue to the end of the line and 2-bit pixel data (00) representing background color pixel ".circle-solid.".
Assume that run-length data before compressed like the one shown in FIG. 7B is input to encoder 200 in FIG. 10. Encoder 200 performs run-length compression (encoding) of the input data by software processing based on compression rules 1 to 6 in FIGS. 5A-5F.
The coding header (2 to 14 bits according to rules 2 to 5 in FIGS. 5B-5E) of run-length compressed sub-picture data SPD is detected by continuous code length detector 106. The number of continuous pixels of identical pixel data in sub-picture data SPD is detected by run-length setter 107 based on a signal from continuous code length detector 106.
More specifically, continuous code length detector 106 counts the number of bits of "0" in the data read from memory 108 in order to detect the coding header (cf. FIGS. 5A-5F). In accordance with the value or content of the detected coding header, detector 106 supplies separation information SEP.INFO. to coding data separator 103.
The operation of decoder 101 in a case wherein compressed pixel data has a 2-bit configuration (rules 1 to 6 in FIGS. 5A-5F are used) will be described.
If all the bits are not "0"s, it is determined that the block length of the unit of compression is 4 bits (see rule 1 in FIG. 5A).
If the bits (upper 2 bits) are "0"s, the subsequent 2 bits (upper 4 bits) are checked. If they are not "0"s, it is determined that the block length of the unit of compression is 8 bits (see rule 2 in FIG. 5B).
If the bits (upper 4 bits) are "0"s, the subsequent 2 bits (upper 6 bits) are checked. If they are not "0"s, it is determined that the block length of the unit of compression is 12 bits (see rule 3 in FIG. 5C).
If the bits (upper 6 bits) are "0"s, the subsequent 8 bits (upper 14 bits) are further checked. If they are not "0"s, it is determined that the block length of the unit of compression is 16 bits (see rule 4 in FIG. 5D).
If the bits (upper 14 bits) are "0"s, it is determined that the block length of the unit of compression is 16 bits, and identical pixel data continue up to the end of the line (see rule 5 in FIG. 5E).
If the number of bits of the pixel data read up to the end of the line is an integer multiple of 8, the pixel data is used as it is. If the number of bits is not an integer multiple of 8, it is determined that 4-bit dummy data is required at the end of the read data to realize byte-aligning (see rule 6 in FIG. 5F).
In decoder 101 in FIG. 11, in order to cope with such a case, pixel color data for compensating for a line shortage is prepared in advance. When a line shortage is actually detected, the current display mode is switched to an insufficient pixel color data display mode. More specifically, when a data end signal is supplied from address control 109 to display activator 110, display activator 110 sends a color switching signal (COLOR SW SIGNAL) to pix. color out-stage 104. In response to this switching signal, pix. color out-stage 104 switches the mode of outputting decoded pixel color data from the encoded data to the mode of outputting decoded color information (COLOR INFO. ) from display activator 110. This switched state is kept during an insufficient line display interval (DISPLAY ENABLE=active).
FIGS. 8A-8C show two display modes (non-interlaced display and interlaced display) to explain how character pattern "A" of the pixel data (sub-picture data) encoded in FIGS. 7A-7C is decoded.
Decoder 101 in FIG. 11 can be used to decode compressed data like the one shown in FIG. 8A into interlaced display data like the one shown in FIG. 8B.
In contrast to this, when compressed data like the one shown in FIG. 8A is to be decoded into interlaced display data shown in FIG. 8C, a line doubler for scanning the same pixel line twice (e.g., re-scanning line #10, in an even field, which has the same contents as those of line #1 in an odd field; switching in units of V-SYNC pulses) is required.
When an image display amount-equivalent to that in the interlaced display mode is to be displayed in the non-interlaced display mode, another line doubler (e.g., line #10 having the same contents as those of line #1 at the lower end portion in FIG. 8C) is made to follow line #1; switching in units of H-SYNC pulses.
Upon detection of an odd field, microcomputer 112 supplies, to select signal generator 118, a mode signal indicating that the current field is an odd field. As a result, select signal generator 118 outputs a signal to selector 115 to select decoded data from decoder 101. Decoder 101 then outputs the pixel data (see FIG. 8C) of lines #1 to #9 in the odd field, as an video output, to an external unit through selector 115. In this case, the pixel data of lines #1 to #9 in the odd field are temporarily stored in line memory 114.
Upon detecting that the odd field has shifted to an even field, microcomputer 112 supplies, to select signal generator 118, a mode signal indicating that the current field is an even field. As a result, select signal generator 118 outputs a signal to selector 115 to select the data stored in line memory 114. Line memory 114 then outputs the pixel data (see FIG. 8C) of lines #10 to #18 in the even field, as a video output, to the external unit through selector 115.
In this manner, the sub-picture image (character "A" in FIG. 8C) of lines #1 to #9 in the odd field is synthesized with the sub-picture image (character "A" in FIG. 8C) of lines 10# to #18 in the even field, thereby realizing interlaced display.
In decoder 101 having the above arrangement, sequentially input bit data are read by 2 to 16 bits while being counted bit by bit from the beginning of a decoded data unit block, and are decoded, instead of being decoded after read by one line. In this case, the bit length (4 bits, 8 bits, 12 bits, 16 bits, or the like) of one decoded data unit is detected immediately before a decoding operation. For example, compressed pixel data is decoded (played back) into three types of pixels (".circle-solid.", "∘", and "#" in FIG. 7) in real time in the unit of the detected data length.
In decoding pixel data encoded according to rules 1 to 6 in FIGS. 5A-5F, decoder 101 may have a bit counter and a data buffer (line memory 114 or the like) having a relatively small capacity. In other words, the circuit arrangement of decoder 101 can be relatively simplified, and the overall apparatus including this encoder can be reduced in size.
A series of encoding operations based on rules 1 to 6 in FIGS. 5A-5F is executed, as software processing, by the microcomputer in encoder 200 in FIG. 10. The overall encoding processing can be performed by encoder 200 in accordance with the flow chart in FIG. 13. Run-length compression of image data in sub-picture data can be performed in accordance with the flow chart in FIG. 14.
FIG. 14 is a flow chart for explaining the contents of encoding 1 (step ST806) in FIG. 13.
From the beginning of this processing, 2 bits are obtained, and it is checked whether the bits are "0". This determination step is repeated (steps ST1101 to STi 109). With this processing, the number of pixels followed, i.e., the number of continuous runs, corresponding to run-length compression rules 1 to 6 is determined (steps ST1110 to ST1113).
* the designated decoding start line address (SPDDADR in FIG. 4) and the decoding end address (SPEDADR in FIG. 4; the address obtained by relatively-shifting by one line from the start line address) are set at address controller 109;
* the display start position, display width, and display height of the decoded sub-picture (SPDSIZE in FIG. 4) are set at display activator 110; and
* the width of display (LNEPIX; although not shown, LNEPIX is part of SPDSIZE in FIG. 4 and indicates the number of dots on one line) is set at coding data separator 103.
Continuous code length detector 106 counts the number of 0-bit of the data read from memory 108, and detects the coding header corresponding to either of rules 1 to 5 shown in FIGS. 5A-5E (step ST1205). Details of detection of the coding header will be described later with reference to FIG. 20.
Then, continuous code length detector 106 generates separation information SEP.IFO. corresponding to either of rules 1 to 5 shown in FIGS. 5A-5E (step ST1206).
FIG. 20 is a flow chart for exemplifying the content of the coding header detection step ST1205 shown in FIG. 18. The processing of the coding header detection can be executed by continuous code length detector 106 shown in FIG. 17 (or HG. 11).
When the content of incremented counter LINCNT does not reach the end of line (NO at step ST1407), decode processing of FIGS. 15 and 16, or the decode processing of FIGS. 18 and 19 is restarted (step ST1408), and the processing returns to step ST1403. To repeat the restart of decoding (steps ST1403 to ST1408), the run-length-compressed sub-picture can be scrolled while it is decoded.
FIG. 24 shows a configuration of a record/playback apparatus for recording on optical disk OD the image information encoded according to the present invention, and for playing back the recorded information to decode it according to the present invention.
Encoder 200 of FIG. 24 is so constructed that it performs the encode processing (corresponding to the processing of FIGS. 13 and 14 ) similar to the encode processing of encoder 200 of FIG. 10, provided that encoder 200 of FIG. 24 executes the encode processing based on a software or hardware (containing a firmware or wired-logic circuits).
The record signal containing sub-picture data encoded by encoder 200, etc. is subjected to, for example, a (2, 7) RLL modulation at modulator/laser driver 702. The modulated record signal is sent from laser driver 7 0 2 to a high-power laser diode mounted in optical head 704. A particular pattern corresponding to the record signal is written in a magneto-optical disk or phase-change optical disk OD by means of the recording laser from optical head 704.
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Filed Jul. 21, 1998.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6253025 *Sep 19, 1997Jun 26, 2001Kabushiki Kaisha ToshibaImage information encoding/decoding systemUS7616863May 13, 2004Nov 10, 2009Kabushiki Kaisha ToshibaInformation storage medium, information reproduction device, information reproduction methodUS7912305Nov 29, 2010Mar 22, 2011Thomson LicensingMethod for run-length encoding of a bitmap data streamUS7929790Dec 1, 2010Apr 19, 2011Thomson LicensingMethod for run-length encoding of a bitmap data streamUS7929791Dec 2, 2010Apr 19, 2011Thomson LicensingMethod for run-length encoding of a bitmap data streamUS7929792Dec 3, 2010Apr 19, 2011Thomson LicensingMethod for run-length encoding of a bitmap data streamCN100574435COct 20, 2006Dec 23, 2009财团法人工业技术研究院Image compressing method* Cited by examinerClassifications U.S. Classification382/232, G9B/20.001, 375/E07.202, 386/E09.013, 375/E07.273International ClassificationH04N1/64, H03M13/51, H04N7/52, F42B10/64, H04N5/85, H04N1/41, H04N9/804, G06T9/00, G11B20/12, H03M7/46, H04N9/82, H04N7/32, H04N9/806, G11B20/00Cooperative ClassificationH04N19/00957, G11B20/00007, H04N9/8227, H04N21/236, H04N21/434, H04N9/8063, H04N9/8042, G11B20/1217, H04N5/85, H03M7/46European ClassificationH04N21/236, H04N21/434, G11B20/12D, H04N7/26Z12, G11B20/00C, H03M7/46, H04N9/804BLegal EventsDateCodeEventDescriptionAug 31, 2011FPAYFee paymentYear of fee payment: 12Aug 29, 2007FPAYFee paymentYear of fee payment: 8Aug 27, 2003FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google