Research And Implementation Of Bar Code Displacement Sensor

The bar code positioning technology provides an effective detection and method for measurement of specific parameters such as settlement and deformation of high-speed track and subgrade.In this paper,the bar code displacement sensor was developed,which is composed of a coding bar code ruler and a corresponding decoding device.It can not only be assembled together for close,contact or non-contact,high-precision measurement,but also can be split for long-distance,large range,non-contact,high-precision measurement.We can use it to easily set up measurement system,which can realize high-precision network automation measurement for these specific parameters.In this paper,on the basis of studying barcode coding scheme,barcode recognition method and decoding algorithm,we propose a multi cycle interval displacement barcode decoding scheme,and design the bar code ruler.We designed a displacement bar code acquisition processing and decoding device which takes the embedded ARM processor as the core.We completed the circuit design and production,selection of electronic component.In addition,we built the optical system and made the device sample.We designed the barcode image processing method and compiled the decoding algorithm,which can realize the corresponding function and the measurement index of the bar code displacement sensor.We designed the experimental scheme to evaluate the performance of the sensor.The results show that the repeatability of the sensor is less than 1?m,the stability is less than 4?m/weeks,the accuracy is ±5?m and the measurement frequency is 50Hz.Finally,we give the application of the sensor in high-speed track and subgrade settlement and deformation measurement.