Bar code, two-dimensional code distinction and composition structure introduction
Bar codes (one-dimensional codes) and QR codes are mainly used as the identification of items. Bar code is mainly used in product identification, anti-counterfeiting, medical supervision, supermarket cashier and other occasions, two-dimensional code can contain more information, such as website, text, pictures, and so on, and even a poem, an article, etc., in the network era, the application is gradually popular and fast.
The difference between:
1. Two-dimensional code carries much more information than one-dimensional code
The information part of a one-dimensional code can only be letters and numbers, and its size is relatively large, which means that its space utilization is low. This determines the limitation of little information. It has a small data size of about 30 characters. Qr codes, on the other hand, carry a lot of information and can contain up to 1,850 characters. The information content can include letters, numbers, kanji, characters, katakana, etc. It's very informative. Therefore, the two-dimensional code has been gradually accepted by the market, and the addition of Chinese characters has opened up the big market in China.
2. They express information differently
According to its characteristics and structure, we can see that the one-dimensional code can only express the commodity information in the horizontal direction, but does not express any information in the vertical direction. Its height is usually to facilitate the alignment and reading of barcode equipment. The two-dimensional code can express information in both horizontal and vertical directions, that is to say, it stores information in a two-dimensional space.
3. The external structure of the two is different
According to Figures 1 and 2, their structures are completely different. A one-dimensional code is a bar code that uses bars to express information in the horizontal direction. It's more like a rectangle. Two-dimensional code can be said to be a square, in its internal three "back" type of anchor points, can help bar code equipment focus, easy to read data. It is the difference in their structure that makes the one-dimensional code without strong error correction function. If the barcode is damaged, it cannot be read. For the two-dimensional code, even if there is damage, it can also be read normally. The error correction rate of damage can reach 7%~30%.
4. The code system of the two is different
In the current code system, one-dimensional code and two-dimensional code each has its own code system and constituent members. The commonly used one-dimensional code system includes: EAN code, 39 code, cross 25 code, UPC code, 128 code, 93 code, ISBN code, and Codabar code, etc.; Commonly used two-dimensional Code system includes: PDF417 two-dimensional bar Code, Datamatrix two-dimensional bar Code, QR Code, Code 49, Code 16K,Code one, etc.
5. The form of expression in barcode printing software is different
One-dimensional code and two-dimensional code can be said to be two completely different bar codes, and their production and expression forms in barcode printing software are also different. Generally speaking, one-dimensional code and two-dimensional code are represented separately in the software. That is to say, when making bar codes, we should first distinguish between the one-dimensional code or two-dimensional code to do, and choose the code system to do. For example, in the leading barcode printing software, these two types of barcode respectively have and to distinguish the representation. The former represents a one-dimensional code, and the latter represents a two-dimensional code.
6. Performance of advantages and disadvantages
The advantage of the one-dimensional code is that it expresses information in one direction, and its height is usually to facilitate the alignment of the scanner. The one-dimensional code can improve the speed of information entry and reduce the error rate. The disadvantage is that the data capacity is relatively small, the need for computer database, one-dimensional code can not be read after being destroyed, low fault tolerance rate.
The advantages of two-dimensional code are large information capacity, wide coding range, low cost, easy to make, do not need the database itself can store a large amount of data, two-dimensional code fault tolerance mechanism to ensure that the picture part is damaged can also be correctly identified, fault tolerance rate can be up to 30%. The disadvantage is easy to be illegal elements implanted virus to steal user information or a variety of fees software.
Composition Structure:
One dimensional code:
barcode is a graphic identifier that uses multiple black bars and blank Spaces with different widths arranged according to certain coding rules to express a group of information. A common bar code is a pattern of parallel lines arranged by black bars (referred to as bars) and white bars (referred to as blanks) with very different reflectance. Its corresponding character consists of a group of Arabic numerals, for people to read directly or through the keyboard to enter data to the computer use. This set of bars and the corresponding characters represent the same information.
The general commodity bar code has 13 digits in total, which is generally composed of four parts: prefix, manufacturer code, commodity code and check code.
Prefix part: The first to third digits are used to identify the country or region code, assigned to the International Article Coding Association, such as 00-09 for the United States, Canada. 45, 49 for Japan. 69 represents Mainland China, 471 represents Taiwan, and 489 represents Hong Kong SAR.
Manufacturer code: composed of the fourth to the seventh digits, it is used to identify different manufacturers and assigns code rights to the article coding organization in each country or region. In China, the National Article Coding Center assigns the manufacturer code.
Commodity code: composed of the 8th to 12th digits, it is the code used by each manufacturer to identify its own commodity. The right of code assignment is exercised by the product manufacturer itself, which can constitute 10,000 different commodity codes.
Check CODE: THE 13TH DIGIT IS USED TO VERIFY THE CORRECTNESS OF THE 1-12 DIGIT FROM THE left in the product barcode. The number of this digit is calculated by the first 12 digits according to a certain rule. If the number of the first 12 digits calculated according to the rule does not match the 13th digit, it means that the read fails, which is an error detection measure of barcode.
Qr code:
Two-dimensional bar code (2-dimensional bar code) is a special geometric figure distributed in the plane (two-dimensional direction) according to a certain law of black and white graphics to record data symbol information, two-dimensional code is a more advanced bar code format than one-dimensional code. A one-dimensional code can only express information in one direction (generally horizontal), while a two-dimensional code can store information in both horizontal and vertical directions. One-dimensional codes can only be composed of numbers and letters, while two-dimensional codes can store information such as Chinese characters, numbers and pictures, so two-dimensional codes are much more widely used.
Take the widely used Quick-Response (QR) CODE as an example, which is mainly composed of five parts: location graph, format information, version information, data and error correction information.
Positioning graphics: used for the positioning of two-dimensional code, a total of 3, that is, 3 positioning graphics can identify a rectangle, and can be used to confirm the size and direction of two-dimensional code;
Format information: Exists in all sizes and is used to store some formatted data. Represents the error correction level of the two-dimensional code, divided into L, M, Q, H;
Version information: the specification of the two-dimensional code, in > If Version 7 is later than version 7, reserve two 3 x 6 areas for storing version information.
Data information and Error Correction information: the actual saved Data Code data Code and Error Correction Code (used to correct the error caused by the damage of the two-dimensional code).