Research And Implementation Of The Static Weighing And Linear-code Reading System For Express Logistic Based On Machine Vision

The rapid development of e-commerce and express logistics and the progress of machine vision opened up a new era of intelligent logistics.It is urgent to equip an intellectual device which can alleviate the pressure of express sorting and distribution and improve the timeliness of express delivery sending and receiving under the logistics of our country.The express sorting usually circumstance of poor automatic facilities and low information technologies in based on the information of courier number.Presently,most of the sorting centers in our country depend on the hand-held scanning device to recognize the linear code which is a way of time-consuming and labour-intensive.So,it is imminently to develop an instrument that can auto discern the logistic bar code smartly.The machine vision detection technology has flourished in recent years.The linear code detection techniques based on image processing is also gradually achieved attention.According to the actual demanding,this thesis designed and implemented the express intelligent bar code recognizing system based on the machine vision.The main research contents are as follow:Firstly,compared to the hand held scanner,the advantages of low cost and high efficiency using machine vision technology to identify the linear code in present working environment are illustrated.According to the corresponding design requirements,the framework of the semi-automatic static weighing and bar code reading system is determined.Then,analysing the structure of the system in brief and describing the evidence of selecting appropriate hardware are carried out.Finally,the layout of the whole system are determined.Secondly,in the aspect of linear code detection and recognition,after exploring the structure characteristics of the bar code,the method of fast cartoon texture decomposition is utilized to enhance the area of linear code and to avoid the disadvantage of using image binarization operation which is prone to generate disturbances on the basis of texture feature that the stripes alternate arranged in the linear yards.Then,the way of grey morphology open operation and the improved adaptive threshold segmentation algorithm are taken advantage to extract the candidate region.Ultimately,the bar code region is coarse localized by using the geometric feature.Thirdly,the attribute that the edges of the bar code are parallel to each other is adopted to subdivide the linear code.Being different from the traditional line segment extraction algorithm,the LSD operator is used to extract the parallel edges between the stripe and space of a linear code under the complex background.Finally,some critical parameters are set to pick up the accurate linear code region.Fourthly,as respect to the problem of decoding,the structure of bar code is first to be introduced and the coding scheme for current domestic express is followed to analyzed in detail.Then,to solve the decoding difficulties that caused by the factors of image blur,linear-code defects and bending distortion,the adaptive iterative decoding method which needs to solve simultaneous equations to acquire the edge position coordinates is proposed.And to ensure the accuracy of decoding,a procedure of calibration and correction is designed.Finally,a linear-code recognition system is designed by the tools of MFC and OPENCV to make the system implementation.