Method of reading two-dimensional code and storage medium thereof
US6360948B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 24, 1999 |
| Grant date | Mar 26, 2002 |
| Priority date | — |
| Expiry date | Nov 24, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/1417
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of reading information out of a two-dimensional code made up of a matrix of cells having a given optical pattern is provided. The two-dimensional code has location symbols used to locate the two-dimensional code and alignment symbols used to locate the cells. The method first calculates a central position of each of the alignment symbols in an image of the two-dimensional code using a predetermined positional relation to the location symbols and selects one of reference patterns which matches up with an optical pattern formed with a pixel lying at the calculated central position of the alignment symbol and surrounding pixels. The method specifies an actual central position of each of the alignment symbols in the image of the two-dimensional code using the matched reference pattern. This compensates for a locational error between the calculated central position and the actual central position of each of the alignment symbols due to deformation of the image taking place, for example, when the two-dimensional code is printed on a round object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.