Image analysis – Pattern recognition
Reexamination Certificate
1999-06-28
2003-11-18
Mariam, Daniel G. (Department: 2621)
Image analysis
Pattern recognition
C382S100000, C382S137000, C382S140000, C382S175000, C382S183000, C382S194000, C235S460000, C235S462090, C235S462100
Reexamination Certificate
active
06650776
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a two-dimensional code recognition processing method, a two-dimensional code recognition processing apparatus, and a storage medium for allowing a computer to execute a two-dimensional code recognition processing program. More particularly, the invention relates to a two-dimensional code recognition processing method, a two-dimensional code recognition processing apparatus, and a storage medium for allowing a computer to execute a two-dimensional code recognition processing program, the method and the apparatus providing efficient and accurate recognition of code data based on image data of a suitably captured two-dimensional code.
The so-called bar code system is used extensively in various industrial fields. The system involves encoding in bars alphanumeric characters representing types and conditions of goods and articles, and typically attaching such codes to the goods and products so that the codes may be scanned later for retrieval of relevant information (e.g., about their types and conditions).
FIG. 20
shows a so-called one-dimensional bar code. In this example, a bar code label
500
is made up of a code part
501
and an ID (identification number) part
502
. The code part
501
is a combination of different widths of bars (in black) and bar-to-bar gas (blanks). The ID part
502
indicates a code contained in the code part
501
. Specifically, the ID part
502
shows as readable information alphanumeric characters that are coded in the code part
501
. This type of one-dimensional bar code
500
is scanned by an optical recognition apparatus called a bar code scanner for recognition.
One way of reading the above-described one-dimensional bar code
500
is by use of a CCD video camera. As more and more bars are arranged to accommodate growing volumes of coded information, however, it becomes increasingly difficult for the video camera to read such one-dimensional bar codes
500
properly.
The difficulty in capturing large amounts of bar-coded information with the video camera is circumvented illustratively by a two-dimensional code system proposed to replace the one-dimensional bar code. As depicted in
FIG. 21
, various kinds of two-dimensional codes have been proposed, each code comprising a code part
601
and an ID part
602
. The code part
601
has a plurality of black square cells arranged two-dimensionally according to predetermined layout rules. The ID part
602
indicates a code that is contained in the code part
601
.
Greater quantities of information are represented when the information is coded two-dimensionally than if the one-dimensional code
500
is used. In other words, it is easier for the video camera to read large quantities of information if the information is coded two-dimensionally rather than one-dimensionally.
The two-dimensional code
600
has one disadvantage. That is, when the video camera picks up an image of a two-dimensional code
600
for code recognition, it is often difficult to distinguish the code from smear, dirt or other distracting images nearby. The result is that code data are often difficult to recognize precisely.
As with the one-dimensional bar code
500
, the above-mentioned two-dimensional code
600
has the ID part
601
indicating the code in question in a human-readable format such as that of alphanumeric characters. With the two-dimensional code
600
, however, it is impossible to recognize just what the code
600
signifies, to what code system the code
600
may possibly belong, or according to what layout rules the square cells making up the code are arranged two-dimensionally.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the above and other disadvantages of the prior art and to provide an apparatus and a method for recognizing code data efficiently and accurately from image data representing two-dimensional codes.
In carrying out the invention and according to one aspect thereof, there is provided a two-dimensional code recognition processing method for recognizing a two-dimensional code made of a plurality of square cells arranged in accordance with predetermined layout rules, the method comprising the steps of: generating binary data from image information acquired externally in accordance with a predetermined threshold value; detecting a reference cell serving as a reference in recognizing the two-dimensional code based on the binary data generated in the binary data generating step; detecting corner cells each located in a predetermined search range with respect to the reference cell detected in the reference cell detecting step, on the basis of the binary data generated in the binary data generating step; and detecting code data assigned to the two-dimensional code existing inside an area of a code part enclosed by the reference cell and by the corner cells on the basis of the binary data generated in the binary data generating step.
According to another aspect of the invention, there is provided a two-dimensional code recognition processing apparatus for recognizing a two-dimensional code made of a plurality of square cells arranged in accordance with predetermined layout rules, the apparatus comprising: binary data generating means for generating binary data from image information acquired externally in accordance with a predetermined threshold value; reference cell detecting means for detecting a reference cell serving as a reference in recognizing the two-dimensional code based on the binary data generated by the binary data generating means; corner cell detecting means for detecting corner cells each located in a predetermined search range with respect to the reference cell detected by the reference cell detecting means, on the basis of the binary data generated by the binary data generating means; and code data detecting means for detecting code data assigned to the two-dimensional code existing inside an area of a code part enclosed by the reference cell and by the corner cells on the basis of the binary data generated by the binary data generating means.
According to a further aspect of the invention, there is provided a storage medium for storing a two-dimensional code recognition processing program for recognizing a two-dimensional code made of a plurality of square cells arranged in accordance with predetermined layout rules, the program being executable by a computer and comprising the steps of: generating binary data from image information acquired externally in accordance with a predetermined threshold value; detecting a reference cell serving as a reference in recognizing the two-dimensional code based on the binary data generated in the binary data generating step; detecting corner cells each located in a predetermined search range with respect to the reference cell detected in the reference cell detecting step, on the basis of the binary data generated in the binary data generating step; and detecting code data assigned to the two-dimensional code existing inside an area of a code part enclosed by the reference cell and by the corner cells on the basis of the binary data generated in the binary data generating step.
As outlined above, through the use of the inventive two-dimensional code recognition processing method, two-dimensional code recognition processing apparatus and storage medium storing a two-dimensional code recognition processing program, binary data are generated from externally acquired image information in accordance with a predetermined threshold value. A reference cell is detected from the binary data thus generated, the reference cell serving as a reference in recognizing a two-dimensional code. Corner cells are detected from within a predetermined search range with respect to the reference cell. Code data are then detected which are assigned to the two-dimensional code existing in an area of a code part enclosed by the reference cell and by the corner cells.
Other objects, features and advantages of the invention will become more apparent upon a reading of the followi
Ihara Keigo
Nakajima Shinji
Rekimoto Junichi
Sueyoshi Takahiko
Frommer William S.
Frommer & Lawrence & Haug LLP
Mariam Daniel G.
Smid Dennis M.
Sony Corporation
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