Research On Visible Light Indoor Positioning Technology Based On Imaging Sensor

With the rapid development of wireless communication and the popularity of smart terminals,indoor positioning technology based on location services has a wide range of application prospects.Visible light communication has many advantages such as no electromagnetic radiation,good confidentiality,rich spectrum resources,and low cost,so it has developed rapidly.At the same time,indoor positioning technology based on visible light communication has also received widespread attention.After studying the related technologies of visible light indoor positioning based on imaging sensors,this thesis studies in detail the problems of low positioning accuracy when part of beacons of multi-light indoor positioning system are blocked,low identification rate of beacon light source ID using standard light fringe code analysis,and short communication distance of visible light positioning system using light fringe code analysis coordinate data,and gives some optimization schemes.The main research work of this thesis is as follows:1)A visible light indoor positioning method based on a single light source is presented,which solves the problem that the positioning accuracy cannot meet the needs in a multi-light source indoor positioning system where the beacon is blocked or the light source arrangement is limited,and the adaptability of visible light positioning is improved.Place a fixed size geometric mark with a prominent feature on the edge of the circular illumination LED light source so that the light source forms an image with a specific shape on the imaging sensor.The relative position of the positioning terminal and the light source is calculated based on the relative relationship between the mark and the light source image.The experimental data shows that the average positioning error of the positioning terminal at different vertical heights is less than 19 cm in a single lighting source area with a length,width,and height of 3m×2m×3m.2)An image processing scheme is proposed to solve the problems of low recognition rate and low anti-interference capability of using standard optical fringe codes to analyze beacon light source ID.According to the mapping relationship between the stripe width of the light fringe code and the flicker frequency of the light source,image processing operations such as histogram equalization,binarization,and ellipse fitting are performed on the single-light source fringe code image to detect the flicker frequency of the light source,so as to realize the light source ID information Obtained,the experimental data shows that within a vertical height of 270 cm,the recognition rate is higher than 80%.3)The light spot image detection method is proposed to solve the problems of short communication distance and low anti-interference capability of a visible light positioning system using light fringe codes to analyze coordinate data.And image operations such as gamma enhancement,Ostu segmentation,and ellipse detection are performed on the speckle image.Detect the light and dark state of the light source,analyze the light spot image,and analyze the light source coordinate data.The experimental data shows the light spot image detection method,the coordinate data transmission distance is 15 m,and the bit error rate is less than 5%.4)Based on the extraction of light spot images,a monocular ranging method based on BP neural network is given.The light spot images taken at different distances at the receiving end have a non-linear quantitative relationship between the average gray value and the distance.This thesis uses BP The neural network trains the distance and the corresponding average gray value of the spot image,and estimates the distance between the receiving end and the beacon light source.Experimental data shows that the measurement error is less than 6.4% in the 1.4m range.In summary,this thesis conducts research from three aspects: the indoor positioning algorithm of visible light based on imaging sensor,ID recognition of beacon light source,and visible light communication distance.The research results obtained have laid a good foundation for the development of visible light positioning technology.