Research On Indoor Positioning Technology Based On LED And QR Code

Location technology is a hot issue in the research of communication engineering.It is very important in the aspect of disaster relief, personnel location and weaponry.So international scholars do a lot of study about that. Location technology is divided into two parts: indoor location and outdoor location.The study of outdoor location is much longer, so it has achieved many good results,and applied successfully. Under the indoor influence, the outdoor location in indoor location positioning has a lot of restrictions, and thus the precision is lost. So indoor location has developed slowly, but with the sustainable development of real estate in countries, international scholars put more attention on it.Therefore the study in this article has important engineering practical value.At present,the indoor location technology based on visible light communication is still on its early stage, literature about it is not much,and the most are based on theoretical analysis and simulation study.Countries like Japan, USA, Italy, South Korea, European Union and organizations have a lot of attention on visible light indoor technology. Domestic study about this starts later, but recently some universities and research institutions have some related studies, such as Tsinghua University, Beijing University of Posts and Telecommunications, Nanjing University of Posts and Telecommunications and so on.In2012, Xu Zhengyuan team from Tsinghua University designed a indoor visible light LBS location service system, and certified its feasibility through the experiment.In2015, the project team starting from the use of visible light communication in indoor location, came up with a scheme that is based on indoor visible light multi-parameter fingerprint database, simulated and confirmed it and had a pretty result.Due to the interference and grating effect of the visible light, this system still exists some problems in the design and recognition process of two-dimension code made by LED.In this paper, the studies not only followed the research mentioned above, but also study some problems among them, and get better effect.First of all, the research status of visible light domestic and overseas and basic knowledge about two-dimension has been summarized. It also summarized the problems LED two-dimension code indoor location is faced with,then reviewed and simply introduced the indoor location system designed by the project team.Secondary, this article introduces the problems which appear in the design of LED two-dimension code and describes the reason of these problems, such as adjacency light overlap,interference grating and speed and precision of two-dimension code recognition.Eventually, the LED problems are under control through image preprocessing.Preprocessing and histogram equalization the two-dimension code photoed by mobile, then smoothing it using wavlet-contourlet transport, and binaryzation it to get black and white code.Finally the two-dimension code recognition algorithm will recognize it and read the LED's location.This paper certifies the correct and feasible of this scheme through simulation study and experiments, works out some problems in the precious system and does better in indoor location.