Registers – Records – Particular code pattern
Reexamination Certificate
1995-12-26
2001-10-16
Tremblay, Mark (Department: 2165)
Registers
Records
Particular code pattern
C235S456000, C235S462090
Reexamination Certificate
active
06302329
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital information recording carrier having digital information recorded in the form of a two-dimensional pattern on a recording surface of the carrier. The invention also relates to a digital information recording method and apparatus which can produce such digital information carriers. Further, the invention relates to a digital information decoding method and apparatus which can read and decode digital information recorded on such a digital information carrier.
2. Description of the Prior Art
FIG. 50
shows a two-dimensional data code which has been used in a method for recording digital information by arraying a matrix two-dimensionally on a recording surface (see U.S. Pat. No. 4,939,354). The two-dimensional data code is to record digital information by virtually setting matrix meshes corresponding to bits on a recording surface
220
of a recording carrier, and by assigning to each mesh a white or black color representing data.
In such a recording method, generally, control information representing the orientation of an information recording area
219
and the size of a cell (data density) is provided for reading convenience's sake. In the example of
FIG. 50
, as the control information, the perimeter of the rectangular information recording area
219
is provided with a linear portion
212
on its two adjoining sides
221
and a clocking information portion
216
on the remaining two sides
231
. The linear portion
212
is formed of adjoining black cells, and the clocking information portion
216
is formed of alternately connected white and black cells. During a reading operation, the orientation of the information recording area
219
is detected due to the linear portion
212
, and the size of cells is detected through the clocking information portion
216
.
In the above conventional digital information recording method, however, the clocking information portion
216
will be farther away from the data as the size of the information recording area
219
increases. This is because the clocking information portion
216
is provided along the perimeter of the information recording area
219
. As a result, due to factors such as distortion of the recording surface
220
, characteristics of the reading device (scanner, CCD camera, etc.), or the like, a large difference in data position between recording and reading operations will be caused in the vicinity of the center of the information recording area
219
, resulting in reading errors. For example, instead of originally intended information on a cell of the fifth row, the fourth column, the information on the cell of the sixth row, the fifth column may be erroneously read. Consequently, the conventional digital information recording method has a problem that the size of the information recording area
219
cannot be increased and therefore that the storage capacity cannot be increased.
SUMMARY OF THE INVENTION
The present invention has been developed with a view to substantially solving the above described disadvantages and has for its essential object to provide a digital information recording carrier which can prevent the occurrence of reading errors over the entire range of the information recording area even if the size of the information recording area is increased, and therefore which allows the storage capacity to be increased.
Another object of the present invention is to provide a digital information recording method and apparatus which can produce such a digital information recording carrier.
A still further object of the present invention is to provide a digital information decoding method and apparatus which can read and decode digital information recorded on such a digital information recording carrier.
In order to achieve the aforementioned objects, the present invention provides a digital information recording carrier, comprising:
a planar recording surface having an information recording area in which cells corresponding to bits are virtually set in a matrix form, each cell being provided with an optically recognizable mark corresponding to digital information so that the digital information is recorded in the information recording area as a two-dimensional pattern; and
specific patterns each consisting of a plurality of cells which are linked together or contiguous and which are given optically recognizable marks in a given pattern, the specific patterns including a predetermined pattern which is placed in an inner portion apart from a perimeter of the information recording area.
In this digital information recording carrier, predetermined patterns are disposed inside apart from the perimeter of the information recording area. Therefore, even if the information recording area is distorted in the vicinities of its center, the positions of cells in the vicinities of the center of the information recording area are accurately determined based on the positions of the specific patterns. Accordingly, few or no reading errors will in the vicinities of the center of the information recording area even if the size of the information recording area is increased. Also, for the peripheral part of the information recording area, the occurrence of reading errors is prevented by providing clocking information as in the prior art or by providing the specific patterns. As a consequence, it is possible to increase the storage capacity by increasing the size of the information recording area.
In one embodiment, the specific patterns are dispersedly arranged all over the information recording area. In this case, the position of any arbitrary cell is accurately determined over the entire range of the information recording area. As a consequence, it is possible to increase the storage capacity by increasing the size of the information recording area.
In one embodiment, the cells each have a shape of a square of same size. And, each specific pattern is composed of a central closed area with a shape of a square and a loop portion surrounding the central closed area entirely. The central closed area consists of four cells each provided with a light as an optically recognizable mark and the loop portion consists of twelve cells each provided with a dark as an optically recognizable mark.
In another embodiment, each specific pattern is composed of a central portion with a shape of a square, a first loop portion surrounding the central portion entirely, and a second loop portion surrounding the first loop portion entirely. The central portion consists of a single cell provided with a dark as an optically recognizable mark, the first loop portion consists of eight meshes each provided with a light as an optically recognizable mark, and the second loop portion consists of sixteen cells each provided with a dark as an optically recognizable mark.
In these cases, it is easy to find the specific patterns in the information recording area. Also, the number of cells constituting the specific pattern is relatively small. Further, when an identical or similar pattern appears nearby as the recorded information, the specific pattern will not easily overlap the nearby pattern. Still, the specific pattern is less affected by dirt or ink blurs during printing. Besides, the algorithm to find the specific patterns becomes simplified.
In one embodiment, the specific patterns are arranged with higher density in a peripheral part of the information recording area than in an interior of the information recording area. In this case, the reading precision for the peripheral part where distortion is more likely to occur due to the reading device characteristics is enhanced so that the occurrence of reading errors is prevented.
In another embodiment, the specific patterns are placed with higher density in the interior of the information recording area than in the peripheral part of the information recording area. In this case, the reading precision for the vicinities of the center of the information recording area is enhanced so that the occurrence of readi
Aoki Atsushi
Esashi Masahiro
Iwai Toshiyuki
Kaminokado Tsukasa
Niwamoto Hiroaki
Conlin David G.
Dike Bronstein Roberts & Cushman IP Group
Sharp Kabushiki Kaisha
Tremblay Mark
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