Content uploaded by Sumit Tiwari
Author content
All content in this area was uploaded by Sumit Tiwari on Apr 16, 2021
Content may be subject to copyright.
An Introduction To QR Code Technology
Sumit Tiwari
Dept. of Technical Education
SITS Educators Society
Jabalpur, Madhya Pradesh, India
sumittiwari.email@gmail.com
Abstract— QR i.e. “Quick Response” code is a 2D matrix code
that is designed by keeping two points under consideration, i.e. it
must store large amount of data as compared to 1D barcodes and
it must be decoded at high speed using any handheld device like
phones. QR code provides high data storage capacity, fast
scanning, omnidirectional readability, and many other
advantages including, error-correction (so that damaged code
can also be read successfully) and different type of versions.
Different varieties of QR code symbols like logo QR code,
encrypted QR code, iQR Code are also available so that user can
choose among them according to their need.
Now these days, a QR code is applied in different application
streams related to marketing, security, academics etc. and gain
popularity at a really high pace. Day by day more people are
getting aware of this technology and use it accordingly. The
popularity of QR code grows rapidly with the growth of
smartphone users and thus the QR code is rapidly arriving at
high levels of acceptance worldwide.
Keywords— QR code; Quick Response code; QR code
structure; QR Code Encoding; QR Code Decoding.
I. I
NTRODUCTION
A QR code is a type of matrix bar code or two-dimensional
code that can store data information and designed to be read by
smartphones. QR stands for “Quick Response” indicating that
the code contents should be decoded very quickly at high
speed. The code consists of black modules arranged in a square
pattern on a white background. The information encoded may
be text, a URL or other data [1] [2]. The QR code was
designed to allow its contents to be decoded at high speed.
The popularity of QR codes is growing rapidly all around the
world. Nowadays, mobile phones with built-in camera are
widely used to recognize the QR Codes.
QR Codes are created by the Toyota subsidiary Denso
Wave in 1994, and was initially used for tracking inventory in
vehicle parts manufacturing.
The idea behind the development of the QR code is the
limitation of the barcode information capacity (can only hold
20 alphanumeric characters).
While they are developed for tracking parts in vehicle
manufacturing, QR codes now are used in many other fields,
from commercial tracking to entertainment, in-store product
labeling, and in those applications that are aimed at smartphone
users. Users may open URL; receive text after scanning QR
codes. By using QR code generating sites or apps, users can
generate and print their own QR codes for others to scan and
use.
The QR code system consists of a QR code encoder and
decoder. The encoder is responsible for encoding data and
generation of the QR Code, while the decoder decodes the data
from the QR code.
Figure 1 shows the overview of the QR code working. The
plain text, URL, or other data are given to the QR code
encoder, and it generates the required QR code and when we
want to access the data of the QR code, QR code is decoded
via QR Code decoder (scanner) which retrieves the data of QR
code [1] [3].
II. I
NFORMATION
C
APACITY AND
V
ERSIONS OF THE
QR
C
ODE
The symbol versions of the QR Code range from Version 1
to Version 40 [4]. Each version has a different module
configuration or number of modules. (The module refers to the
black and white dots that make up QR Code.)
"Module configuration" refers to the number of modules
contained in a symbol, commencing with Version 1 (21 × 21
modules) up to Version 40 (177 × 177 modules). Figure 2
shows the module configuration of the basic QR codes.
Fig. 1 Working (overview) of QR Code
Fig. 2 Version module configuration of the QR Codes
2016 International Conference on Information Technology
978-1-5090-3584-7/16 $31.00 © 2016 IEEE
DOI 10.1109/ICIT.2016.38
39
Each QR Code symbol version has the maximum data
capacity, according to the amount of data, character type and
error correction level. In other words, as the amount of data
increases, more modules are required to comprise QR Code,
resulting in larger QR Code symbols. Table 1 show the data
capacity of version 40 for different type of data.
III. QR
C
ODE
E
RROR
C
ORRECTION
QR Code employs error correction to generate a series of error
correction codewords which are added to the data codeword
sequence which enable symbol to be read even if it is dirty or
damaged. The QR code achieves powerful error-correction
capability by using Reed-Solomon codes, a widely used
mathematical error-correction method. Four levels of error
correction are available, higher level has high capability of
recovery. Table 2 shows error-correction levels and their
approximate ability of error correction.
When selecting the level of error correction, environmental
conditions as well as the desired size of the QR Code symbol
need to be taken under consideration.
For example, Level Q (25% error correction) or H (30%) may
be required for factories or other applications where the QR
Code is likely to become dirty or damaged. For clean
environments and codes containing a large amount of data,
Level L (7%) may be selected. In general, Level M (15%) is
most frequently used [3] [4].
IV. S
TRUCTURE
O
F
A
QR
C
ODE
Each QR Code symbol shall be built of square modules
arranged in a regular square array and shall consist of function
patterns and encoding region. And the whole symbol shall be
surrounded on all four sides by a quiet zone border [4] [5].
Function patterns are the shapes that must be placed in
specific areas of the QR code to ensure that QR code
scanners can correctly identify and orient the code for
decoding. There are 4 types of function patterns; they are
finder pattern, separator, timing patterns, and alignment
patterns.
Encoding region contains data, which represents version
information, format information, data and error correction
codewords. Fig 3 illustrates the structure of a QR Code
symbol.
• Finder Pattern: Finder patterns are the special position-
detection patterns located in three corners (upper left,
upper right, and lower left) of each symbol.
It consists of an outer dark square that is 7 × 7 modules,
an inner light square that is 5 × 5 modules, and a solid
dark square in the center that is 3 × 3 modules. The
ratio of module widths in each position detection
pattern is 1:1:3:1:1, as shown in fig. 4.
The finder pattern is designed to be a pattern that
is unlikely to appear within the other sections of
TABLE I. D
ATA
C
APACITY OF
QR
C
ODE
V
ERSION
40
TABLE II. E
RROR
C
ORRECTION
L
EVELS
A
ND
%
O
F
C
ORRECTION
Fig. 3 Structure of a QR Code symbol
Fig. 4 Finder Pattern
40
the QR code so that QR code scanners can search for
this ratio of light to dark modules to detect the finder
patterns and correctly orient the QR code for decoding.
• Separators: Separators are the one-module wide areas
of whitespace between each finder pattern and encoding
region.
• Timing Patterns: There are 2 timing patterns, i.e.
horizontal timing pattern and vertical timing pattern.
They are consisting of alternating dark and light
modules. The horizontal timing pattern is placed in the
6th row of the QR code between the separators. The
vertical timing pattern is located in the 6th column of
the QR code between the separators. These patterns are
helpful in determining the symbol density, module
coordinates and version information area.
• Alignment Patterns: An alignment pattern is constructed
of 5 × 5 dark modules, 3 × 3 light modules and a single
dark module in the center. QR codes that are version 2
and larger must have alignment patterns and the number
of alignment patterns depends on the symbol version.
• Encoding Region: Encoding region contains format
information, version information, data and error
correction codes. For format information, one-module
array must be reserved near the top-left, top-right,
bottom-left finder pattern and version information, an
area of a 6 × 3 block above the bottom-left finder
pattern and a 3 × 6 block to the left of the top-right
finder pattern is reserved.
• Quiet Zone: It is a 4-module wide area containing no
data, and it used to ensure that the surrounding text or
markings should not misguide the QR code data.
V. E
NCODING AND
D
ECODING
O
F
A
QR
C
ODE
A. Procedure for the generation/encoding of a QR Code
In order to convert input data into a QR code symbol, we’ll
go through some step [4] [5] [6]; figure 5 shows an overview
of the encoding process.
• Data Analysis: A QR code encodes a string of text. The
QR standard has four modes for encoding text: numeric,
alphanumeric, byte, and Kanji. Each mode encodes the
text as a string of bits (1s and 0s), but each mode uses
a different method for converting the text into bits, and
each encoding method is optimized to encode the data
with the shortest possible string of bits.
Therefore, first step should be to perform data analysis
to determine whether text can be encoded in numeric,
alphanumeric, byte, or Kanji mode, and then select the
most optimal mode for your text.
• Data Encoding: Next step is to encode text. The result
of this step is a string of bits that is split up into data
codewords that are each 8 bits long.
The mode used for encoding is identified by the Mode
Indicator, which is a string of 4 bits. Encoded data must
start with the appropriate mode indicator which is used
for encoding.
The number of characters that are being encoded is
represented by the string of bits known as Character
Count Indicator. Character Count Indicator is placed
after the mode indicator and its length is version
dependent.
• Error Correction Coding: QR codes use error
correction. This means that the string of data bits that
represent our text, we must then use those bits to
generate error correction codewords using a process
called Reed-Solomon error correction.
QR scanners read both the data codewords and the error
correction codewords. By comparing the two, the
scanner can determine that it reads the data correctly or
not, and if it did not read the data correctly it can correct
errors.
• Structure Final Message: The data and error correction
codewords generated in the previous steps must now be
arranged in the proper order. For large QR codes, the
data and error correction codewords are generated in
blocks, and these blocks must be interleaved according
to the QR code specification.
• Module Placement in Matrix: After generating the data
codewords and error correction codewords and
arranging them in the correct order, you must place
the bits in the QR code matrix. The codewords are
arranged in the matrix in a specific way.
Fig.5 QR code encoding
41
• Data Masking: Certain patterns in the QR code matrix
can make it difficult for QR code scanners to correctly
read the code. To counteract this, the QR code
specification defines eight mask patterns, each of which
alters the QR code according to a particular pattern.
• Format and Version Information: The last step is to add
format and (if necessary) version information to the QR
code by adding pixels in particular areas of the code
that were left blank in previous steps. The format pixels
identify the error correction level and mask pattern
being used in this QR code. The version pixels
encode the size of the QR matrix and are only
used in larger QR codes [4].
B. Procedure for decoding a QR Code
Decoding data from the QR code is the reverse of the
encoding procedure. Figure 6 shows an overview of the
decoding process [5] [6].
• Recognizing Modules: Recognize dark and light
modules as an array of “0” and “1” bits by locating
and getting an image of the symbol.
• Extract Format Information: Decode the format
information and release the masking pattern and
apply error correction on the format information
modules as necessary. Also obtain a mask pattern
reference.
• Determine Version Information: If version
information is applicable then decode it from the
version information area and then determine the
version of the QR code symbol.
• Release Masking: In order to release the masking,
XOR the encoding region bit pattern with the Mask
Pattern whose reference has been extracted from the
format information.
• Restore Data and Error Correction Codewords:
Restore the data and error correction codewords of
the message by reading the symbol characters
(according to the placement rules for the model).
• Error Detection and Correction: By utilizing the
error correction codewords, identify errors and if any
error is detected, correct it.
• Decode Data Codewords: Divide the data codewords
into segments according to the Mode Indicators and
Character Count Indicators. And finally, decode the
data characters according to the mode(s) in use and
output the decoded text as result.
VI. T
YPE
O
F
QR
C
ODES
QR Codes are categorized into five broad categories [6].
A. QR Code Model 1 & 2
The original QR Code is QR Code Model 1, a code capable of
coding 1,167 numerals with its maximum version being 14 (73
x 73 modules).
QR Code created by improving Model 1 so that this code
can be read smoothly even if it is distorted in some way.
QR Codes that are printed on a curved surface or whose
reading images are distorted due to the reading angle can be
read efficiently by referring to an alignment pattern embedded
in them.
This code can encode up to 7,089 numerals with its
maximum version being 40 (177 x 177 modules).
Fig.6 QR code decoding
Fig. 7 Type of QR Codes
42
B. Micro QR Code
This QR Code is only one orientation detecting pattern
code so that it can be printed in a smaller space. A major
feature of Micro QR Code is it has only one position detection
pattern, compared with a regular QR Code that require a
certain amount of area because position detection patterns are
located at the three corners of a symbol.
Furthermore, QR Code requires at least a four-module
wide margin around a symbol, whereas a two-module wide
margin is enough for Micro QR Code. This configuration of
Micro QR Code allows printing in areas even smaller than QR
Code.
C. LogoQ (Logo QR Code)
The Logo QR Code is a novel type of QR Code created to
enhance visual recognizing-ability by blending it with letters
and pictures in full color.
Since LogoQ is a highly designable type of QR Code, it
becomes possible to differentiate LogoQ from the ordinary QR
Code.
Since a proprietary logic is used when generating LogoQ
codes, it is possible to combine design-ability and readability.
D. iQR Code
iQR Code is a matrix-type 2D code, allowing easy reading
of its position and size. This code allows a wide size range of
codes from ones smaller than the traditional QR Code and
Micro QR Code to large ones that can store more data than
these.
This code can be printed as a rectangular code, turned-over
code, black-and-white inversion code or dot pattern code
(direct part marking) as well, leaving a broad range of
applications in various areas.
E. Encrypted QR Code
Encrypted QR Code is a type of QR Code equipped with
reading restricting function. This can be used to store private
information and to manage a group which is capable of
accessing QR Code information. Basically, an encrypted QR
Code is a QR Code, which contains encrypted data.
In Encrypted QR Code system, data information is
encrypted by using encryption techniques and then the
encrypted data is applied to the QR Code encoder (generator)
which generates the QR Code. Later this QR Code is first
scanned and decoded by the QR Code decoder then data
information is retrieved using decryption techniques. Figure 8
show an overview of encrypted QR code mechanism.
VII. M
ERITS AND
D
EMERITS
O
F
QR
C
ODE
A. Merits of the QR Code
• Omnidirectional and Fast Scanning: QR code can be
read much faster and scanned from any angle within
360 degrees i.e. no need to align the scanner with the
code symbol.
• Small Size: QR code takes less space. A QR Code
can hold the same amount of data contained in a 1-D
barcode in only one-tenth the space.
• Huge Data Storage Capacity: QR code has high data
storage capacity. A single QR Code symbol can
contain up to 7,089 numerals (200 times the amount
of data storage capacity of the traditional 1-D
barcode).
• Many Types of Data: The QR Code can handle
numerals, alphanumeric characters, Japanese,
Chinese or Korean characters and binary data.
• Error correction: Error correction technique used in
QR codes enables successful decoding of the code
symbol even if up to 30% of the data is dirty or
damaged.
• Direct Marking: The QR Code due to high degree of
readability under low-contrast conditions allows
printing of a symbol directly onto a part or product.
• Available for Everyone: Anyone can make their own
QR code according to their need, for example, user
can create QR code of the URL of its own website
for advertising purpose.
• Wide Range of Uses: There are lots of potential uses
of QR codes. They can be used to extend the user
experience in store, restaurants, websites and more.
B. Demerits of the QR Code
Although QR code has many positive points on its side but,
there are some demerits of the QR code too, such as, Need of
QR code scanner; to decode the code users must have a QR
reader app, which limits the audience; Security issues, before
scanning a code, the scanner can never really know where the
code is going to lead them; Lack of public awareness, large
portion of population is still unaware of this technology.
VIII.
A
REA
O
F
A
PPLICATIONS
Although the QR Code was originally designed to track
automotive components but, now these days it is rapidly used
in many other areas where traditional barcodes are used, such
as Manufacturing, Retailing, Healthcare, and Transportation
[7]. Also, QR code found useful in some novel application
Fig.8 Concept of Encrypted QR Code
43
fields including mobile marketing, online advertising,
electronic ticket/coupon, electronic payment, identification,
academics[8], information security, OMR sheet tampering
detection [9] etc.
Mobile marketing gains popularity and has recently
witnessed rapid growth, where the QR Code increasingly
appears in print and online advertising, as well as on signs,
hoardings, posters, and other particulars.
By scanning a QR Code with a smartphone, consumers can
be connected to a relevant Web page or receive targeted
marketing messages such as a special offer, discount coupon,
product or store information, etc.
IX. I
MPACT
A
ND
G
ROWTH
O
F
QR
C
ODE
I
N
T
ODAY
’
S
E
RA
QR codes are quickly arriving at high degrees of
acceptance. More and more people adopt and use this
technology every day. One of the reasons behind the rapid
growth of the QR code is that it gains momentum as
smartphone users grow across the world and marketers use QR
codes to reach mobile consumers.
QR codes first started to appear in marketing campaigns in
2011-2012. Even then, when there was significantly low
smartphone and mobile internet penetration, QR codes mark
their presence in the market. A study held in 2012 shows that
Americans were the most likely to have used the technology.
According to the study of 2,000 Americans and 1,000
Europeans undertaken by Pitney Bowes, US consumers
frequently scan QR codes across every medium by which the
codes were delivered.
In July 2012, comScore reported that there were 5.1 million
QR code users in Germany, 3.3 million in the UK and another
3.4 million in Spain.
The use of code scanning has gone up during the past years,
as awareness and adoption of QR Codes grow exponentially.
QR code stats done by ScanLife shows that, 23 million QR
codes are scanned during the first quarter of 2015, which is
nearly 10 million more than during the first quarter of 2012,
and the first quarter of 2012 had posted a 157 percent increase
as compared to the first quarter of 2011 [10].
X. C
ONCLUSION
In this paper, we studied QR code technology, its benefits,
application areas, and its impact on marketing and
technological world. Initially, QR code are developed and use
for inventory tracking stuff but, now these days, they found
applications in many new areas like marketing, advertising,
secure payment systems, education industries, etc.
Adoption of the QR codes grows rapidly during past years
and number of users increases exponentially, due to its features
like high data storage capacity, fast scanning, error-correction,
direct marking and ease of use.
A
CKNOWLEDGMENT
We would like to convey our very great appreciation to our
mentors for their unceasing encouragement about this
paperwork.
R
EFERENCES
[1] Dong-Hee Shin, Jaemin Jung, Byeng-Hee Chang “The psychology
behind QR Codes: User experience perspective” ,Science Direct,
Computers in Human Behavior 28 (2012) pp 1417-1426.
[2] Phaisarn Sutheebanjard, Wichian Premchaiswadi, “QR Code
Generator”, IEEE 2010 8th International Conference on ICT and
Knowledge Engineering (24-25 Nov. 2010) pp 89-92.
[3] QR Code, http://www.qrcode.com/en/
[4] QR Code Tutorial, http://www.thonky.com/qr-code-tutorial/
[5] ISO/IEC 18004:2000. “Information technology-Automatic identification
and data capture techniques- Bar Code symbology- QR Code ”, 2000.
[6] Y. Yan, H.W. Liu, “Research and Application of Encoding and
Decoding Tech. of QR Code”, University of Science and Tech, Beijing,
[7] T. Sriram, V.K. Rao, “Application of barcode technology in automated
storage & retrieval systems”, Industrial Electronics Conference
Proceedings. Taipei, 1996, pp. 5-10.
[8] R. Dorado, E. Torress, C. Rus, "Mobile learning: Using QR codes to
develop teaching material", IEEE - Technologies Applied to Electronics
Teaching (TAEE) 2016, Seville, Spain,22-24 June 2016.
[9] Sumit Tiwari, Sandeep Sahu, “A Novel Approach for the Detection of
OMR Sheet Tampering Using Encrypted QR Code”, IEEE -
International Conference on Computational Intelligence And Computing
Research (2014), Coimbatore – India, 2014, pp. 604-608.
[10] ScanLife.com, “QR Code Adoption: Trends and
Statistics”,www.scanlife.com
TABLE IV. S
TUDY REPORT BY
S
CAN
L
IFE
TABLE III.
S
TUDY REPORT BY
S
CAN
L
IFE
44
