条形码的概念
条形码是由一组规则排列的条、空以及对应的字符组成的标记，“条”指对光线反射率较低的部分，“空”指对光线反射率较高的部分，这些条和空组成的数据表达一定的信息，并能够用特定的设备识读，转换成与计算机兼容的二进制和十进制信息。主要分为一维条码和二维条码。
由于受信息容量的限制，一维条码仅仅是对"物品"的标识，而不是对"物品"的描述。故一维条码的使用，不得不依赖数据库的存在。要用一维条码表示汉字的场合，显得十分不方便，且效率很低。二维条码解决了一维条形码的限制性，因为它具有高密度、高可靠性等特点，所以可以用它表示数据文件(包括汉字文件)、图像等。二维条码是大容量、高可靠性信息实现存储、携带并自动识读的最理想的方法。
条形码是迄今为止最经济、实用的一种自动识别技术。条形码技术具有以下几个方面的优点
A．输入速度快：与键盘输入相比，条形码输入的速度是键盘输入的5倍，并且能实现“即时数据输入”。
B．可靠性高：键盘输入数据出错率为三百分之一，利用光学字符识别技术出错率为万分之一，而采用条形码技术误码率低于百万分之一。
C．采集信息量大：利用传统的一维条形码一次可采集几十位字符的信息，二维条形码更可以携带数千个字符的信息，并有一定的自动纠错能力。
D．灵活实用：条形码标识既可以作为一种识别手段单独使用，也可以和有关识别设备组成一个系统实现自动化识别，还可以和其他控制设备联接起来实现自动化管理。
历史发展
A 条码的研究始于美国，二十世纪20年代，诞生于威斯汀豪斯（Westinghouse）的实验室里,发明家John Kermode提出最早的条码概念。
B 1949年 在专利文献中首先出现条码符号，由诺姆·伍德兰Norm Woodland和伯纳德·西尔沃Bernard Silver注册了第一个机器识读的条码
C 1972年，交叉二五码由Intemec公司的David Allais博士发明，提供给Computer-Identics公司，此条码可在较小的空间内容纳更多的信息。
NCR公司推出彩色条码，用于零售POS系统。
D 1973年UPC条码标准宣布。
E 1974年，Intermec公司David Allais博士和RaySterens研制出--三九码
F 1976年，欧洲采用了他们自己的UPC码，称为EAN(欧洲货品编码)。
G 1981年，Computer Identic公司推出128码
H 1987年，第一个二维条码49码由David Allais博士研制，Intermec公司推出。
I 1988年，Laserlight系统公司的Ted William推出第二种二维条码16K码。
J 1990年，Symbol公司推出二维条码PDF417
K 1991年4月,“中国物品编码中心”代表中国加入“国际物品编码协会”。
The concept of code
Bar code is composed of a set of rules, empty and characters of the mark, "light" refers to a low albedo part, "empty" refers to the light, these high reflectivity and empty composed of data express a certain information, and to use specific equipment starts with computer, converts binary compatible with the decimal information. Mainly divided into one-dimension code and 2d barcode.
Due to the limited information capacity, one-dimension code is just to "items" logo, rather than on the "items". Therefore, the use of one-dimension code to depend on the existing database. To use the Chinese one-dimension code says, appear very inconvenient, and low efficiency. Two dimensional barcode to solve the one-dimensional barcode restrictive, because it has the characteristics of high density and high reliability etc, so can use it to represent data files (documents), including Chinese image etc. 2d barcode is large capacity and high reliability information storage, carry the most ideal and automatically with the method.
Bar code is by far the most economical, practical an automatic identification technology. Bar code technology has the advantages of the following several aspects
A. input speed: compared with the keyboard input speed, bar code is five times the keyboard input, and can realize real-time data input "."
B. high reliability: keyboard input data error rate for three per cent, using optical character recognition rate for PPM, while using barcode technology ber than a million to one.
C. collection of information: using traditional one-dimensional barcodes can be gathering dozens of character of information, 2d barcodes can carry more information of thousands of characters, and a certain degree of automatic correction ability.
D. flexible barcode identification is practical: as a recognition method can be used alone, also can form a relevant identification equipment and automation system identification, also can connect with other control equipment automation management.
The historical development
A study of American bar, began in the 1920s, was born at the westin problem.your Westinghouse (of) the lab, inventor John Kermode put forward the concept of the bar.
B in the patent document in 1949, the first barcode symbols WuDeLan noam Norm Woodland and Bernard silva walter miserable first level registered with the machine
C in 1972, 25 yards across the company by dr David Intemec Allais invention, provide the Computer company, the bar Identics - in smaller space for more information.
NCR company, used in retail color bar POS system.
D 1973 UPC barcodes standard announced.
E in 1974, dr David Allais Intermec company is developed and RaySterens - 999 yards
F in 1976, Europe adopted their own UPC codes, called EAN (European goods code).
G in 1981, Computer Identic company launched 128 yards
H in 1987, the first two dimensional barcode by dr David Allais 49 yards, Intermec company.
I Laserlight system in 1988, the company launched a second Ted William two-dimensional barcode 16K yards.
J Symbol in 1990, the company launched PDF417 2d barcode
K April 1991, "Chinese" article numbering center of China to join "the international association of coding." items