Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
1999-01-04
2001-10-23
Decady, Albert (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
Reexamination Certificate
active
06308296
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a coded image recording device and method for recording optically readable coded images on the surface of a recording medium such as paper.
As a conventional coded image recording device which records an optically readable coded image on a recording medium (paper in particular), there is a technique of recording a coded image comprising multiple blocks having a physical format on paper, which is disclosed in EP No. 0,670,555A1(U.S. Ser. No. 08/407,018) now U.S. Pat. No. 5,896,703 assigned to the same assignee as this invention. This recording device records multimedia information, such as sound, images, text, etc., as a coded image and can be adapted to varying amounts of data in input multimedia information by increasing the number of blocks, each of which constitutes a physical minimum storage unit, according to the data amount.
Each of the blocks has an ID number referred to as a block address. A coded image is recorded on paper by concatenation of a plurality of blocks. An increase in the number of blocks that can be concatenated leads to an increase in the amount of recordable information. However, the use of an optical reader of a manual scanning type will increase the probability of the occurrence of a read error due to meanderings of scanning attendant an increase in scanning range. Such a read error will produce frequently dropouts of blocks, i.e., so-called burst errors, which makes difficult a reliable read operation by manual scanning.
In view of the prior art problem, EP No. 0,713,914A1(U.S. Ser. No. 08/586,792) now U.S. Pat. No. 5,898,709 by way of example discloses a technique related to a logical data format that allows even a manual-scanning reader to read data recorded in blocks with more certainty and a coded image recording device that produces and records a coded image based on the logical data format.
Hereinafter, the arrangement of such a coded image recording device will be described with reference to FIG.
15
.
In this figure, the data input unit and the code printing unit are omitted because they are not directly related to the present invention to be described later.
In
FIG. 15
, digitized multimedia information is entered into a data compression unit
21
, which receives from a controller
29
identification information that represents the type of sound, images, or text. By this identification information, one of compressors in the data compression unit is selected, thereby subjecting the input multimedia information to compression corresponding to the identification information and producing desired compressed data. In the structure of the compressed data, a header is added which defines the data type, the compression scheme, and the compressed data amount. The amount of compressed data with such a header is presented to the controller
29
.
A dummy data generation unit
23
generates dummy data which is added so that supermacroblock data
191
shown in
FIG. 16
is divisible by one macroblock data in a macroblock data group
193
. Here, a supermacroblock, a macroblock and block data used in the following description correspond to data, a first block, and a second block (or simply a block), respectively. In addition, macroblock user data and block user data correspond to first block data and second block data (or unit block data), respectively. All these expressions are used in the following description.
The compressed data and the dummy data are entered into an error correcting code generator
22
, which receives correction capability information from the controller
29
. The error correcting code generator
22
adds given error correcting and checking parity to the compressed data having a data amount determined according to the error capability information and generates correcting codes. The correcting code length and the parity length corresponding to the correction capability are sent to an interleave unit
24
and a macroblock header generator
25
. The correcting codes thus generated are entered into the interleave unit
24
and stored in sequence into a buffer memory (not shown) in the interleave unit on the basis of the input correcting code length. The logical data format of a group of the correcting codes thus stored has a two-dimensional structure as shown in supermacroblock data
191
of FIG.
16
. The number of the correcting codes corresponds to the interleave length.
EP No. 0,713,914A1(U.S. Ser. No. 08/586,792) describes that supermacroblock data is an integral multiple of macroblock data, but does not describe any specific structure of the supermacroblock data. A specific structure of the supermacroblock data is described in EP No. 0,703,580A2. In the technique disclosed in this publication, dummy data is appended to compressed data so that supermacroblock data is an integral multiple of macroblock data and correcting parity is affixed to the dummy data with the dummy data taken as part of the compressed data.
The supermacroblock data
191
has dummy data added to the end of compressed data to form a given size of supermacroblock data. Here, the dummy data may be a predetermined fixed value or a random number generated in accordance with a predetermined rule. The supermacroblock data
191
is written into the buffer in the direction of correcting code length and read from the buffer into a macroblock data generator
26
in the direction of the interleave length. Thereby, interleave processing is completed, so that logically one-dimensional supermacroblock data
192
is produced. The interleave length is presented to the macroblock header generator
25
.
The macroblock header generator
25
produces a header based on the input correcting code length, parity length, and interleave length, and the ID number of the supermacroblock and the ID number of a macroblock output from the controller
29
, i.e., information representing how the macroblocks are concatenated to form a supermacroblock. Error correcting parity is appended to produce a final macroblock header. The macroblock header is output to the macroblock data generator
26
.
In the macroblock data generator
26
, the one-dimensional supermacroblock data
192
after interleave is divided into pieces of macroblock user data each corresponding to macroblock data having a given data amount. Each piece of macroblock user data is assigned a macroblock header to produce a group of macroblock data
193
. The macroblock data group
193
is entered into a block data generator
27
where each macroblock data is divided into multiple pieces of block user data.
Each piece of block user data comprises data obtained by dividing each of the macroblock header and macroblock user data by the number of pieces of block data in each macroblock data.
A block header is appended to each piece of block user data, thus producing a block data group
194
. The block header contains block-related header information such as a block address.
The block data group
194
is entered into a coded image generator
28
, which converts each block data into a block comprised of markers
112
, pattern codes
113
, block headers
114
, and block user data
115
as shown in
FIG. 3
, and produces a code image in which multiple blocks are concatenated. The block user data
115
is recording modulated to discriminate between data
115
and markers
112
and recorded in black and white dots each for a bit.
The above-described conventional technique appends control information that makes each of the interleave length and the error correcting capability variable according to the amount of data in the input multimedia information, i.e., a macroblock header, for each macroblock by way of example and thereby checks an increase in the percentage of multimedia information of the control information, i.e., a reduction in recording density, to a minimum. Thus, the reader can detect the control information with more certainty.
Hereinafter, the reason will be described taking others than the above-described technique by way of example will be described.
First, in the conve
Chase Shelly A
De'cady Albert
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Olympus Optical Co,. Ltd.
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