05726435 is referenced by 298 patents and cites 25 patents.

A two-dimensional code 1 consists of three positioning symbols 2, a data region 3, timing cells 4 and an apex detecting cell 5. The shape of the whole code 1 is a square having the same number of vertical and lateral cells. A scanning line passing through the center of each positioning symbols 2 always gives a constant frequency component ratio--dark:light:dark:light:dark=1:1:3:1:1, irrespective of the scanning direction. For this reason, even if a rotational angle of the two-dimensional code is not certain, the specific frequency component ratio of each positioning symbol 2 can be easily detected by executing only one scanning operation in a predetermined direction. Hence, the coordinates of the center of each positioning symbols 2 can be easily found. Thus, the position of the two-dimensional code 1 is quickly identified.

Title
Optically readable two-dimensional code and method and apparatus using the same
Application Number
8/403548
Publication Number
5726435
Application Date
March 14, 1995
Publication Date
March 10, 1998
Inventor
Yuji Uchiyama
Aichi-ken
JP
Takayuki Nagaya
Nagoya
JP
Tadao Nojiri
Oobu
JP
Motoaki Watabe
Toyokawa
JP
Masahiro Hara
Nagoya
JP
Agent
Cushman Darby & Cushman IP Group of Pillsbury Madison & Sutro
Assignee
Kabushiki Kaisha Toyota Chuo Kenkyusho
JP
Nippondenso
JP
IPC
G06K 7/10
G06K 19/06
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