Information-processing system using free-space optical communication and free-space optical communication system
US7715723B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Jul 27, 2005 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Mar 16, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J14/0227
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a system for data communication between an information terminal to be operated by a user and remote communication nodes, the present invention intends to suppress the power consumption of the information terminal. For that purpose, communication nodes 2, 3 and 4 each emit diffuse light carrying a pilot signal blinking at a low frequency to notify the presence of the communication node and an ID signal belonging to a higher frequency range, the ID signal containing inherent address etc. for identifying each communication node. A mobile phone 1 as the information terminal captures an image and processes the image data to detect the pilot signal of each communication node. Then, determining the position of each node and setting a limited range for reading the pixels around that position, the mobile phone 1 reads the detection signals of the pixels within the limited range at high speed and obtains identification information. This information is used to identify each node and eliminate influences of any other light source that apparently resembles the pilot signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.