Transcript
Seminar Report ’12 QR Code
QR CODE
Submitted By, JIBIN MATHEW
ABSTRACT Dept. of Computer Science
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Seminar Report ’12 QR Code
A QR (quick response) code is a two - dimensional barcode, readable by QR scanners, smart mobile phones with a camera. QR codes can be used to link to any URL. They can also be used to automatically add information into a user's Smartphone such as a calendar event, map or personal contact information. A QR code is capable of storing several hundred times more information than a conventional barcode and is readable from any direction. A QR Code system is used in combination with a QR Code printer (or QR Code creation software) and QR Code scanner. QR Code is generated with QR Code creation software and a special printer. A QR Code is a matrix code (or two-dimensional bar code) created by Japanese corporation DensoWave in 1994. The "QR" is derived from "Quick Response", as the creator intended the code to allow its contents to be decoded at high speed.
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Seminar Report ’12 QR Code
INTRODUCTION Quick Response (QR) codes are versatile. A piece of long multilingual text, a linked URL, an automated SMS message, a business card or just about any information can be embedded into the two-dimensional barcode. Coupled with moderate equipped mobile devices, QR Codes can connect the users to the information quickly and easily. The low technical barrier of creating and reading QR codes allows innovative educators to incorporate them into their educational endeavors. The operations to retrieve or store QR codes are incredibly simple and quick, and with mobile devices, make them the ideal educational tools for teaching and learning. QR codes are everywhere and most people have mobile phones equipped with QR code readers.. Although QR codes existed for over fifteen years, there are not so many research applications in this area. QR code was developed by Denso-Wave, a Japanese automatic data capture equipment company (Denso, 2009), in 1994. “QR” stands for “Quick Response.” It is readable by moderately equipped mobile phones with cameras and QR scanners. Information such as URL, SMS, contact information and plain text can be embedded into the two dimensional matrix. With smart phones, we can visit the Website linked by the URL quickly, we can send the SMS message directly or we can save the contact information onto the address book easily.
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Seminar Report ’12 QR Code
QR CODE QR Code is a form of 2D bar codes. A sample is shown in Figure 1. A QR code is capable of holding 7,089 numeric characters, 4,296 alphanumeric characters, 2,953 binary bytes, 1,817 Kanji characters or a mixture of them. The data capacity is much higher than other 2D codes such as PDF417, Data Matrix and Maxi Code (Denso, 2010b). It stores information in both vertical and horizontal directions. A QR code can be read from any direction in 360° through position detection patterns located at the three corners as shown in Figure 1. A QR code can be read even it is somewhat distorted by either being tilted or on a curved surface by alignment patterns and timing patterns. The error correction capability against dirt and damage can be up to 30%. A linking functionality is possible for a QR code to be represented by up to 16 QR codes at maximum so that a small printing space is possible. The size of a QR code can vary from 21x21 cells to 177x177 cells by 4 cell-increments in both horizontal and vertical direction.
Figure 1. A QR code sample
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Seminar Report ’12 QR Code
Data can be easily encrypted in a QR code to provide a
confidentiality of information embedded in the code. It can also handle various languages. For examples, there are a number of standards adopted by Asian
Countries like GB/T 18284 by Chinese National Standard in 2000, KS-X ISO/IEC 18004 by Korean National Standard in 2002, and TCVN7322 by Vietnam National Standard in 2003. There are two types of QR Codes. 1. ONLINE CODES Online codes are codes that point to an Internet address and trigger a client / server interaction that requires an active Internet connection or phone service. This typically involves the access of a mobile website, the sending of an SMS message or another action. 2. OFFLINE CODES Offline codes are codes that do not need an Internet connection and are directly resolved on the phone. This includes data retrieved by the phone from the QR code itself, like addresses, text, and phone numbers. In QR Code, Information is encoded in both the vertical and horizontal direction, thus holding up to several hundred times more data than a traditional bar code (Figure 2).
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Seminar Report ’12 QR Code
Figure 2: Barcode QR Codes (Figure 3) have rapidly gained international
popularity and found widespread adoption, especially in Japan where its ability to
encode Kanji symbols by default makes it especially suitable. Popular uses include storing URLs, addresses and various forms of data on posters, signs, business cards, public transport vehicles, etc. For instance, the sports brand Umbro have embedded QR codes into the collars of England football shirts, sending fans to a secret website where prizes can be won.
Figure 3: QR Code
Although initially used for tracking parts in vehicle manufacturing, QR codes are now used in a much broader context, including both commercial tracking applications and convenience-oriented applications aimed at mobile phone users (known as mobile tagging). QR codes can be used to display text to the user, to add a vCard contact to the user's device, to open a URI or to compose an email or text message. Users can also generate and print their own QR codes for others to scan and use by visiting one of several free QR code generating sites.
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Seminar Report ’12 QR Code
QR codes storing addresses and URLs may appear in
magazines, on signs, buses, business cards, or on just about any object about which users might need information. Users with a camera phone equipped with the correct reader application can scan the image of the QR Code to display text, contact
information, connect to a wireless network, or open a web page in the phone's browser. This act of linking from physical world objects is known as a hardlink or physical world hyperlinks. Google's mobile Android operating system supports QR codes by natively including the barcode scanner (ZXing) on some models, and the browser supports URI redirection, which allows QR Codes to send metadata to existing applications on the device. Nokia's Symbian operating system is also provided with a barcode scanner, which is able to read QR codes, while mbarcode is a QR code reader for the Maemo operating system. In the Apple iOS, a QR code reader is not natively included, but over 50 free Apps are available with reader and metadata browser URI redirection capability.
LICENSE The use of QR codes is free of any license. The QR code is clearly defined and published as an ISO standard. Denso Wave owns the patent rights on QR codes, but has chosen not to exercise them. The term QR code itself is a registered trademark of Denso Wave Incorporated.
USE IN MARKETING Recently, QR codes have become more prevalent in marketing circles and have been integrated into both traditional and interactive Dept. of Computer Science
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Campaigns. Media where QR codes have been deployed include: billboard ads, guerilla marketing campaigns, in-store displays, event ticketing and tracking, trade-show management, business cards, print ads, contests, direct mail campaigns, websites, email marketing, and couponing just to name a few. QR codes have also been used at trade shows and in conferences.
BACKGROUND In 1970, IBM developed UPC symbols consisting of 13 digits of numbers to enable automatic input into computers. These UPC symbols are still widely used for Point-Of-Sale (POS) system. In 1974, Code 39 which can encode (symbolise) approx. 30 digits of alphanumeric characters was developed. Then in the early 1980s, multistaged symbol codes where approx. 100 digits of characters can be stored such as Code 16K and Code 49 were developed. As informatisation rapidly developed in the recent years, requests had mounted for symbols which can store more information and represent languages other than English. To enable this, a symbol with even higher density than multistaged symbols was required. As a result, QR Code, which can contain 7,000 digits of characters at maximum including Kanji characters (Chinese characters used in Japan) was developed in 1994. The history until realizing high-capacity and highdensity symbols can be described as illustrated in Figure 4 when seeing them from the technology’s aspect. Firstly, Interleaved 2 of 5 and Codabar which can encode (symbolise) numbers were developed, followed by the development of Code 39 which can encode alphanumerical characters. Along with the informatisation developments, it had become necessary to have full ASCII encoded, and this resulted in the development of Code 128. Then, multistaged symbols were developed where these linear symbols were arranged in several stages. Toyota Motor’s Kanban Code is the world’s first multistaged symbol.
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Seminar Report ’12 QR Code
As computers became popular, these codes developed
into multi-row symbols where multistaged codes were extended and into matrix symbols where data were arranged in matrix. The printing areas for matrix symbols
Are the smallest among all, and is seen as highly prospective as the main symbol for the future. QR Code is a matrix symbol which has been developed as the one enabling all of high capacity PDF417, high density printing of data matrix, and high speed reading of maxi code based on the research made on their characteristics. Two-dimensional symbols generally contain much more data amount when compared with linear symbols (approx. 100 times more), and therefore require much longer data processing time and more complex process. Therefore, QR Code has had much consideration for its finder pattern to enable high-speed reading.
Figure 4: The history of symbols
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Seminar Report ’12 QR Code
Figure 5: The development of the symbols
Figure 6: The development of QR Code QR Codes have already overtaken the classical barcode in popularity in some areas. This stems in many cases from the fact that a typical Dept. of Computer Science
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Seminar Report ’12 QR Code
barcode can only hold a maximum of 20 digits, whereas as QR Code can hold up to 7,089 characters. Combined with the diversity and extendability offered, this makes the use of QR Codes much more appealing than that of barcodes. Statistically,
QR Codes are capable of encoding the same amount of data in approximately one tenth the space of a traditional bar code. A great feature of QR Codes is that they do not need to be scanned from one particular angle, as QR Codes can be read regardless of their positioning. QR codes scanners are capable of determining the correct way to decode the image due to the three specific squares that are positioned in the corners of the symbol and the alignment blocks. QR Codes were initially used by vehicle manufacturers for tracking parts. After a while, companies began to see the variety of different use cases for QR Codes. The most popular commercial use for QR Codes is in the telecommunications industry, where the increasing adoption of smartphones seems to be the biggest driver of their popularity. With the technology of mobile phones constantly evolving, especially in the area of mobile internet access, QR Codes seem to be an adequate tool to quickly and efficiently communicate URLs to users. This also allows offline media such as magazines, newspapers, business cards, public transport vehicles, signs, tshirts or any other medium that can accept the print of a QR Code to be used as carriers for advertisements for online products.
Bar Code to 2D Code Bar codes have become widely popular because of their reading speed, accuracy, and superior functionality characteristics. As bar codes became popular and their convenience universally recognized, the market began to call for codes capable of storing more information, more character types, and that could be printed in a smaller space. As a result, various efforts were made to increase the amount of information stored by bar codes, such as increasing the number of bar code digits or layout multiple bar codes. However, these Dept. of Computer Science
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Seminar Report ’12 QR Code
improvements also caused problems such as enlarging the bar code area, complicating reading operations, and increasing printing cost. 2D Code emerged in response to these needs and problems.
Multiple bar code layout
2D Code with stacked bar codes (stacked bar code type)
2D Code (matrix type)
2D Code is also progressing from the stacked bar code method (that stacks bar codes), to the increased information density matrix method.
Typical 2D Code In addition to QR Code, some other kinds of 2D Code have been developed. Below is a table of typical 2D Code and their features. QR Code
PDF417
DataMatri
Maxi Code
x Picture
DENSO(Japan)
Symbol Technologies (USA)
RVSI Acuity CiMatrix (USA)
UPS (USA)
Type
Matrix
Stacked Bar Code
Matrix
Matrix
Numeric
7,089
2,710
3,116
138
Alphanumeric
4,296
1,850
2,355
93
Binary
2,953
1,018
1,556
Kanji
1,817
554
778
Large capacity, small printout
Large capacity
Small printout
Developer(country)
Data capacit y
Main features
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High speed
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Seminar Report ’12 QR Code size High speed scan
size
scan
Main usages
All categories
OA
FA
Logistics
Standardization
AIM International JIS ISO
AIM International ISO
AIM International ISO
AIM International ISO
QR Codes can carry up to several hundred times the amount of data carried by ordinary bar codes. Micro QR code is a smaller version of the QR code standard for applications with less ability to handle large scans. There are different forms of Micro QR codes as well. The highest of these can hold 35 numeric characters. Standard QR code is the QR code standard for applications that possess the ability to handle large scans. A standard QR code can contain up to 7089 characters, though not all QR readers can accept that much data. While the adoption of QR codes in some markets has been slow to begin (particularly in markets such as the United States where competing standards such as Data Matrix exist), the technology is gaining some traction in the smartphone market. Many Android, Nokia, and Blackberry handsets come with QR code readers installed. QR reader software is available for most mobile platforms.
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Seminar Report ’12 QR Code
CHARACTERISTICS OF THE QR CODE Additional to the characteristics for two-dimensional symbols such as large volume data (7,089 numerical character set maximum), high-density recording (approx. 100 times higher in density than linear symbols), and high-speed reading, QR Code has other superiority in both performance and functionalities aspects. a) All-Direction (360°) High-Speed Reading Reading matrix symbols will be implemented by using a CCD sensor (area sensor). The data of the scan line captured by the sensor will be stored into the memory. Then, by using the software, the details will be analyzed, finder patterns identified, and the position/size/angle of the symbol detected, and the decoding process will be implemented. Traditional twodimensional symbols used to take much time for detecting the position/angle/size of the symbol, and had a problem that their readings were less accurate when compared with those of linear symbols. QR Code has finder patterns for notifying the position of the symbol arranged in three of its corners to enable high-speed reading in all
directions (360°). The ratio between black and white among the scan line that runs through the finder patterns is always 1:1:3:1:1 when seen from any direction Dept. of Computer Science
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Seminar Report ’12 QR Code
among the 360° surrounding it. By detecting this specific ratio, the finder pattern can be detected from among the image captured by the CCD sensor to identify the position
of the QR Code in a short period of time. Additionally, by identifying the positional relationships of the three finder patterns listed in Figure 5 from among the image field of the CCD sensor, the size (L), the angle (!), and the outer shape of
the symbol can be simultaneously detected. By arranging the finder patterns into the three corners of the symbol, the decoding speed of the QR Code can be made 20 times faster than that of other matrix symbols. Additionally, detecting finder patterns can be easily implemented by the hardware, and can also be accelerated.
b) Resistant to Distorted Symbols Symbols often get distorted when attached onto a curved surface or by the reader being tilted (angled between the CCD sensor face and the symbol face). To correct this distortion, QR Code has alignment patterns arranged with a regular interval within the range of the symbol. The variance between the Centre position of the alignment pattern estimated from the outer shape of the symbol and the actual Centre position of the alignment pattern will be calculated to have the mappings (for identifying the Centre position of each cell) corrected. This will make the distorted linear/non-linear symbols readable.
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Seminar Report ’12 QR Code
Figure 7: Correcting Distorted Symbols QR Code provides the following features compared with conventional bar codes. c) Data Restoration Functionality (Resistant to Smudged or Damaged Symbols) QR Code has four different error correction levels (7%, 15%, 25%, and 30% per symbol area). The error correction functionality is implemented according to each of the smudge/damage, and is utilizing Reed-
Solomon code which is highly resistant to burst errors. Reed-Solomon codes are arranged in the QR Code data area. By this error correction functionality, the codes can be read correctly even when they are smudged or damaged up until the error correction level. The error correction level can be configured by the user when he/she creates the symbol. So if the code is highly likely to get smudged in the users’ usage environment, it is recommended to have 30% set for this correction level.
Figure 8: Smudged/Damaged Symbols Dept. of Computer Science
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Seminar Report ’12 QR Code
d) Efficiently Encoding of Kanji Characters As a symbology developed in Japan, QR
Code is capable of encoding JIS Level 1 and Level 2 kanji character set. In case of Japanese, one full-width Kana or Kanji character is efficiently encoded in 13 bits, allowing QR Code to hold more than 20% data than other 2D symbologies.
e) Linking Functionality of the Symbols QR Code has a linking functionality which will enable a single symbol to be represented in several symbols by dividing it . A single symbol can be divided into 16 symbols at maximum. The example shown in Figure 8 is one where a single QR Code is divided into four symbols, and each symbol has an indicator showing how many symbols the original symbol had been divided into and in which order that specific symbol would be among all divided ones. This will enable the entire data to be edited and submitted to the computer regardless of what order the symbols had been read by the reader. By this linking functionality, the QR Code will be able to be printed even if the printing space is not wide enough to have a single QR Code printed.
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Seminar Report ’12 QR Code
Figure 9: Linking the Symbols
f) High Capacity Encoding of Data While conventional bar codes are capable of storing a maximum of approximately 20 digits, QR Code is capable of handling several dozen to several hundred times more information. QR Code is capable of handling all types of data, such as numeric and alphabetic characters, Kanji, Kana, Hiragana,
symbols, binary, and control codes. Up to 7,089 characters can be encoded in one symbol.
A QR Code symbol of this size can encode 300 alphanumeric characters.
g) Small Printout Size
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Seminar Report ’12 QR Code
Since QR Code carries information both horizontally
and vertically, QR Code is capable of encoding the same amount of data in approximately one-tenth the space of a traditional bar code. (For a smaller printout size, Micro QR Code is available.
*2: Data restoration may not be fully performed depending on the amount of dirt or damage.
h) Error Correction QR Code has error correction capability to restore data if the code is dirty or damaged. Four error correction levels are available for users to choose according to the operating environment. Raising this level improves error correction capability but also increases the amount of data QR Code size. To select error correction level, various factors such as the operating environment and QR Code size need to be considered. Level Q or H may be selected for factory environment where QR Code gets dirty, whereas Level L may be selected for clean environment with the large amount of data. Typically, Level M (15%) is most frequently selected. QR Code
Error Correction Capability*
Level L
Approx.7%
Level M
Approx. 15%
Level Q
Approx. 25%
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Seminar Report ’12 QR Code
Level H
Approx. 30%
*Data restoration rate for total codewords (codeword is a unit that constructs the data area. One codeword of QR Code is equal to 8 bits.)
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Seminar Report ’12 QR Code
THE QR CODE STRUCTURE QR Code is a matrix type symbol with a cell structure arranged in a square. It consists of the functionality patterns for making reading easy and the data area where the data is stored. QR Code has finder patterns, alignment patterns, timing patterns, and a quiet zone.
Figure 10: The QR Code Structure a) Finder Pattern A pattern for detecting the position of the QR Code. By arranging this pattern at the three corners of a symbol, the position, the size, and the angle of the symbol can be detected. This finder pattern consists of a structure which can be detected in all directions (360°). b) Alignment Pattern A pattern for correcting the distortion of the QR Code. It is highly effective for correcting nonlinear distortions. The central coordinate of the
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Seminar Report ’12 QR Code
Alignment pattern will be identified to correct the distortion of the symbol. For
this purpose, a black isolated cell is placed in the alignment pattern to make it easier to detect the central coordinate of the alignment pattern. c) Timing Pattern A pattern for identifying the central coordinate of each cell in the QR Code with black and white patterns arranged alternately. It is used for correcting the central coordinate of the data cell when the symbol is distorted or when there is an error for the cell pitch. It is arranged in both vertical and horizontal directions. d) Quiet Zone A margin space necessary for reading the QR Code. This quiet zone makes it easier to have the symbol detected from among the image read by the CCD sensor. Four or more cells are necessary for the quiet zone. e) Data Area The QR Code data will be stored (encoded) into the data area. The grey part in Figure 10 represents the data area. The data will be encoded into the binary numbers of ‘0’ and ‘1’ based on the encoding rule. The binary numbers of ‘0’ and ‘1’ will be converted into black and white cells and then will be arranged. The data area will have Reed-Solomon codes incorporated for the stored data and the error correction functionality.
THE SPECIFICATIONS OF THE QR CODE The specifications of the QR Code are as described in Table below.
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a) Symbol Size QR Code can have its size freely selected according to the data volume to be stored and the reading method. The symbol size is incremented by four cells in both vertical and horizontal direction - 21x21 cells, 25x25 cells, 29x29 cells..., and there are 40 size types with the maximum size set to 177x177 cells. For example, in the case for 45x45 cells, if a single square cell is sized 0.25mm, one side of the symbol
will be 45x0.25mm = 11.25mm. The quiet zone will need to be added on both sides of the symbol whose minimum size is four cells, and therefore, the space required for having this symbol printed will be a square of (4+45+4)x0.25mm which is 13.25mm. b) Information Type and Volume Dept. of Computer Science
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Seminar Report ’12 QR Code
QR Code can handle various types of data such as numerical characters, alphabets,
signs, Kanji characters, Hiragana, Katakana, control signs, and images. It can basically have character sets supported by ISO/IEC 646 and ISO/IEC 10646. These data can also coexist. The maximum available volume of the information is listed in Table 1. c) Data Conversion Efficiency QR Code has four types of conversion mode - numerical characters, alphanumerical/signs, binary, and Kanji characters - for encoding the data. Each mode has had considerations to improve its conversion efficiency. The number of cells required for each character in each mode is listed in Table 1. d) Error Correction Functionality QR Code has an error correction functionality for restoring the data. There are four different restoration levels so that you can select the level that matches with each usage environment. Each restoration capability is as listed in Table 1.
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Seminar Report ’12 QR Code
Dept. of Computer Science
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Seminar Report ’12 QR Code
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