7/30/2019 COLOR 2D

1/24

COLOR 2D-BARCODES A SURVEY

Abstract

2-D barcodes are used to store data in both x and y dimensions compared to 1-D barcodes. Camera

equipped mobile phones loaded with barcode reading software can decode information contained in a

barcode symbol. This improves the user experience while simplifying the input of data into the mobile

device. Thus 2D barcodes works as an interface between the real and the digital world. Currently ,

there exists a number of different 2D barcodes. Among the black and white codes,Qr codes and Data

Matrix are more popular.

In recent years, colors have been used to increase the data capacity of 2D barcodes. Color barcodes

posses several challenges in a mobile environment. In this paper, I present a survey on color 2-D

barcodes .

Introduction

A bar code is simply a series of stripes (usually black) on a light background (usually white) that

can be scanned and read directly into a computer. The traditional 1D barcodes store information only

in one direction (horizontal) and vertical dimension does not carry any information but only

provides redundancy. One-dimensional (1D) bar-codes, especially UPC [5], are found printed on

packaging of products. These are mainly used in product identification but their use in complex

applications is impossible due to limited data capacity. Hence the 2D barcodes were designed to carry

significantly more data than its 1D counterpart. Fig shows 1-D and a 2-D barcode symbols.

2D barcodes are created by repeating a single 1D code over multiple rows thereby exploiting

bidimensional shapes to represent data. Figure 2 illustrates the evolution of barcode technology. In the

multiple barcode layout, multiple scans are needed to get all the information contained in the

barcode. In the stacked barcode layout, one single scan is enough to obtain the stored information but

the scanning equipment must be carefully aligned with the barcode orientation. In a matrix barcode

layout, information is represented in a two-dimensional way and acquire information with one single

scan.

Recently, cameraequipped mobile phones with high-resolution color displays have become popular .

2-D barcode technology, along with a camera mobile phone can be used for mobile tagging.

Mobile Tagging is the process of [Fig.1]:

7/30/2019 COLOR 2D

2/24

1) capturing the image of the barcode with the camera-equipped mobile phone

2) decoding the image using a software program, called barcode reader and

3) linking to the decoded URL on the world wide web to get more information.

Othe applications include viz; a number can be dialed, a text message can be sent , a back-end

application can be accessed, predefined email or sms , printed (e.g. newspaper, magazine, flyer) ,

billboards ,or mobile payment.

Both the increasing demand for higher density barcodes and the wide availability of on-board cameras

in mobile phones seem to motivate naturally the need for

2D color barcodes. However, the increased data density obtained with the usage

of colors comes at an additional cost. A rescanned image may look similar to the original, but

it may have been distorted during the Print&Scan process. Indeed, reading color

barcodes poses significant computer vision due to following factors.

First, the color balance may be drastically different in different code readers. Second, the images

containing codes may be taken by un-experienced users, and thus the location of the barcode in the

image, its orientation,its slope, etc. can be mostly unconstrained. Furthermore, possible transformations

in the prospective can distort the geometry of the barcode. The light conditions under which the images

are taken can vary dramatically.

Standard 2D Barcodes

Two dimensional barcodes fall into two different classes: stacked barcodes and matrix codes.

3.1.2.1 Stacked barcodes

In a stacked code, several barcodes are arranged one over the other, equivalent to the linking of

individual 1D barcode. Hereby the actual information is encoded along the x-axis, and the row

information in the y-axis. The advantages of stacked codes include the minimal additional effort

in going from 1D to 2D, since the same printing and evaluation systems can be used. Leading

7/30/2019 COLOR 2D

3/24

stacked symbologies include PDF417, Code 49, and Code 16K. Laser scanners, linear imagers and

area imagers are used as bar code reader.

3.1.2.2 Matrix barcodes

Matrix barcodes encode data in dark and light geometric elements arranged in a grid. The

position of each element relative to the center of the symbol is a key variable for encoding.

Recognition of the barcode is possible in any arbitrary position of the code. Matrix codes

must however be equipped with fixed code elements for the recognition of position for the

scanner. The advantage of all matrix codes is the high information density and low space

requirement. Common examples include Data Matrix, MaxiCode, and QR Code etc.

Though each 2D symbol has its own morphological Structure, different symbols may be grouped

in three main classes:

Multi-row (or stacked) codes, in which a set of linear barcodes are stacked together in

a single, multi-row symbols. A typical example is the PDF417.

2D codes with a locating target, in which a special pattern is used to locate the

symbols against a complex or unknown background. Two typical examples are the

Maxicode and the QR-code.

2D codes without a locating target, in which the locating must exploit the internal

structure of the code itself. A typical example is the Data Matrix.

2D barcodes can also be divided into two categories:

Database 2D Barcodes

Index-based 2D Barcodes

7/30/2019 COLOR 2D

4/24

The database 2D barcodes QR Code, Veri Code, mCode and Data Matrix were initially

invented to improve data capacity for industrial applications However, when integrated into

mobile phones with built-in cameras that can scan and decode data; these 2D barcodes can

operate as portable databases, letting users access information anytime, anywhere, regardless

of network connectivity.

The index-based 2D barcodes Visual Code, Shot Code, and Color Code were developed for

camera phones, so they take into account the reading limitations of these built-in cameras.

They have a much lower data capacity than database 2D barcodes, but they offer more robust

and reliable barcode reading. Each barcode basically works as an index that links the digital

world to the real world, so these barcodes require network connectivity. Figure 3.7 presents

these 2D-barcode symbols.

Figure 3.7: Most Commonly used 2D Bar codes for mobile phones

Three barcodes, which are frequently used in camera equipped mobile

phones ,are described .

3.2.1 Quick Response Code: (QR Code)

QR-Code [ISO18004] was developed by the Japanese cooperation Denso Wave

7/30/2019 COLOR 2D

5/24

[Denso03] in 1994. It was initially used for tracking inventory in vehicle parts manufacturing and is

now used for variety of industries. QR stands for Quick Response as the creator intended the code to

allow its contents to be decoded at high speed [8].

QR Codes distinctive feature is its position detection patterns, located at three of symbols

corners (see Figure 3.8a) [9]. The squares in the bottom left, top left, and top right corners are

locator patterns. When a reader scans a symbol, it first detects these patterns. The ratio of the

black and white on a line that passes through the center of the pattern (that is, B: W: B: W:

B) is 1:1:3:1:1 from any angle. This lets the reader quickly find the detection patterns, which

in turn promotes ultra-high speed barcode reading.

In the QR Code standard, corners are marked and estimated so that the inside-code can be

scanned. QR Code can encode all types of data including symbols, binary data, control codes,

and multimedia data. The maximum data capacities are 7,089 characters for numeric data,

4,296 characters for alphanumeric data, and 2,953 bytes for binary data. The symbol versions

of QR Code range from version 1 (21 X 21 modules) to version 40 (177 X 177 modules).

However, mobile applications use only versions 110 to take into account camera phone

limitations.

7/30/2019 COLOR 2D

6/24

Figure 3.8: QR Codes. (a) Symbol Structure [9], (b) Masking Operation [10], (c)

Structure-append feature, which enhances the codes scalability by dividing it multiple

data areas [11].

The features of QR barcode symbol are large capacity, small printout size and high speed

scanning etc. QR code comprised of the following pattern: finder pattern, timing pattern,

format information, alignment pattern, and data cell. The finder patterns located at three

7/30/2019 COLOR 2D

7/24

corners of the symbol intended to assist in easy location of its position, size and inclination.

In 2000 years, QR Code is being issued as National standard in China. QR Code is being

used in a wide variety of applications, such as manufacturing, logistics, and sales

applications.

Several QR Code features can enhance the codes reading robustness, including error

correction, a masking technique [10], and a structured-append function [11]. By applying

Reed-Solomon error correction coding, QR Code can restore upto 30% of available

codewords (8 bits/codeword) even if the symbol is damaged. Four different error-correction

levels are available according to the users requirement: Level L (approximately 7 percent, M

(approximately 15 percent), Q (approximately 25 percent), and H (approximately 30

percent). (The percentages are the data restoration rates for total code wordsa unit that

constructs the data area. One codeword of QR Code is equal to eight bits.)

The masking technique allocates the black and white dots evenly and helps prevent pattern

duplication. This helps readers avoid code misreading so they can quickly process the code.

Eight masking patterns exist, and encoders evaluate each pattern to select the best one (see

Figure 3.8b). So, after masking, if lines and blocks still exist those are the same colors, the

points for the masks are reduced. The encoder selects the mask with the highest mark. The

structured-append function enhances a QR Codes scalability by dividing the code into up to

16 data areas. This means we can break a large QR Code symbol into smaller ones (see

Figure 3.8c), so we can manipulate the codes cell size and data capacity and satisfy the

7/30/2019 COLOR 2D

8/24

limitations of camera phone applications. A decoder can then reconstruct the information

stored in the multiple QR Code symbols. The error correction level and code division depend

on the application, the quality of scanner, or user preference.

3.2.2 Data Matrix Code:

Data Matrix Code was invented by RVSI Acuity CiMatrix (USA). Data Matrix is one of the

most well known 2D barcode standards. Each Data Matrix symbol consists of data region

which contain nominally square modules set out in a regular way. These modules distributes

in matrix elements location and express data information. Data code bit stream is presented

by different combination of unit models distributed at matrix element places [12].

The only advantage of QR code is its ability to efficiently encode Japanese Kanji characters.

Considering all other comparison criteria, Data Matrix is preferred. It has a higher data

capacity for the same code size, being the most space efficient of all 2D symbologies. Data

Matrix Code uses between 30% and 60% less space than a QR Code containing the same

data. The minimum size for QR Code is 21x21 modules, while Data Matrix has a much more

space-efficient minimum size of 10x10 modules

Data Matrix is very compact code. It is very reliable, as it has a powerful error correction

algorithm (Reed-Solomon) built in. It employs the Reed-Solomon error correction to enable

accurate read when substantial parts of the code are distorted. There is reconstruction of the

7/30/2019 COLOR 2D

9/24

data content even after damage to the total code symbol of up to 25%. It provides

omnidirectional readability also at high transport speeds. It is widely used in the automotive,

aerospace and computer manufacturing industries, for large data capacity labelling, such as

direct part marking and package marking. The symbology is in the public domain, free of any

licensing or royalties.

Data Matrix has a finder pattern comprising two solid lines and two alternating dark and light

lines on the symbols perimeter, which is surrounded by a quiet-zone border (see Figure 3.9)

The L shaped solid border defines the physical size, orientation, and symbol distortion, and

the broken border on the opposite corner defines the symbols cell structure.

Data Matrix [13] uses two types of error correction algorithms, depending on the error

checking and correcting level employed. ECC levels 000 to 140 offer five different error-

correction levels and use convolutional code-error correction. However, ECC-200, which is

in common use, uses Reed-Solomon error correction. The symbol size determines ECC-200s

correction level.

Data Matrix ECC-200 symbols have an even number of modules on each side. Although the

maximum size is 144 rows 144 columns, each block size is limited to 24 rows 24 columns

to prevent symbol distortions. When the data exceeds the block size, the symbol is divided

into four blocks. The maximum data capacity is 3,116 digits, 2,335 alphanumeric characters,

or 1,556 bytes. The Data Matrix symbol can be square or rectangle. Several features enhance

7/30/2019 COLOR 2D

10/24

Data Matrixs reading robustness. First is its size. In a comparison with QR Code and Veri

Code in which eight digits were encoded in a .25 mm cell, it created the smallest symbol

(3.3 3.3 mm) and maintained the same level (1015 percent) of error correction.

Figure 3.9: Data Matrix Code (Symbol Structure) [14].

Second, a structured-append function can divide a Data Matrix symbol into 16 multiple

symbols. The original data can be restored from these, regardless of scanning order, by

adding three bytes to each of the smaller symbols. The first additional byte identifies the

position for the particular symbol and the total number of symbols in the sequence. The

remaining two bytes serve as a file (a file is the linked Data Matrices) identifier with a

possible value (or ID number) between 1 and 254 (thus allowing up to 254 x 254 = 64,516

7/30/2019 COLOR 2D

11/24

identifiers). Third, data compaction can compress data before encoding it in a Data Matrix

symbol. This increases the barcodes data capacity. Sema code has adopted the Data Matrix

format to encode plain-text URLs and implement them as physical hyperlinks. For example,

in Figure 3.9, a phone scans a business card to display the companys URL *14+.

3.2.3 Visual Code:

Visual Code [15] was developed to enable Human Computer Interface (HCI) using camera

phones. Each code introduces a code coordinate system with its origin at upper left edge of

the code and one unit corresponding to a single code bit pattern. The code coordinate system

is independent of the orientation of the code in the image. The code recognition algorithm is

able to map arbitrary points in an image plane to corresponding points in the code plane.

Also, camera phones, because they are mobile, sometimes randomly rotate or tilt symbols

when scanning them. Visual Code can use the amount of rotation and tilt in a captured image

as additional input parameters. So, users can obtain different information by rotating the

phone, and the users can continuously update the information by moving the phone. This

enables applications that support real-time interactions between the camera phone and nearby

active displays (see Figure 3.10).

7/30/2019 COLOR 2D

12/24

Fig 3.10: Visual Code (Symbol Structure)

Visual code markers provide a convenient means of storing decodable information about

products. By reading the bit patterns in a marker, a computer vision system, such as a cell

phone equipped with a digital camera, can extract the information and use it to make

decisions about the associated product. In a visual code system developed by Rohs [15], an

83-bit sequence is divided into nine adjacent columns of black and white squares.

These columns form the central region of the marker. The pattern within the central region

will vary between different encodings. What remain fixed, though, are five structures outside

the central region: three corner squares and two rectangles. Altogether, the central region and

surrounding guide elements form an 11-by-11 grid, which defines the entire visual code

marker [16].

Although the data capacity is limited to 83 bits, Visual Code can function both as a portable

7/30/2019 COLOR 2D

13/24

database and as an index to a remote database.

2.1 QR-Code

QR-Code [ISO18004] was developed by the Japanese cooperation Denso Wave

[Denso03] in 1994. QR-Code (Quick Response) is the de facto standard for

Japanese telecommunication providers and handset vendors. 3G Visions *3G Vision+

barcode reader decodes QR-Codes and is installed on 75% of Japanese handsets.

2.1.1 Micro QR-Code

Micro QR-Code is distinct smaller than the original QR-Code. The capacity is very

limited(maximum 35 numeric characters or 21 alphanumeric characters). A barcode

reader decoding QR-Codes is not necessarily able to decode Micro QR-Codes.

2.3 Proprietary Codes

[Semacode06] compares Data Matrix vs. proprietary codes. In the discussion the

expertise of the developers of proprietary codes in comparison to the industry driven

development of Data Matrix is questioned. The availability of technical specifications

and the width of industry support are mentioned as an argument for the standardized

format. The reliance on a single vendor involves risks in case of a change in his

business model or a close down. Proprietary codes may have limited capacity to store

data. The reason behind may be, that the vendor wants to act as a required middleware

service provider.

While the standardized codes will probably get support from manufacturers of mobile

phones, this will most likely not be the case for proprietary codes.

Beetagg

7/30/2019 COLOR 2D

14/24

Beetaggs have been optimised to address some issues of the Western mobile market

[Beetagg08]. E.g. in Japan most mobile phones are equipped with an autofocus and/or

a macro functionality. This is not the case in the Western World so the scanning of

small printed codes is not possible.

Beetagg is designed, to overcome this issue, so that the mark could be encoded

without autofocus and/or a macro lens.

Beetagg allows the placement of a logo for branding in the middle of the symbol. The

developing company states that this is an advantage over the two standardized

barcodes mentioned above. Even the standard does not provide the possibility of

brandingBut also the opportunity of branding is not included in the standards, there

are already QR-Codes and Data Matrix codes holding a logo in the centre.

Color 2D Barcodes

In order to increase data capacity, some 2D barcodes use colors to create more

symbols, resulting in larger data capacity within the same size. There is surprisingly little research work

in the liter-ature on the topic of color barcodes In order to increase the density of information, differ-ent

ink colors could be used. For example, Microsofts density of information (in bits per area unit) is

proportional to log2N, where N is the number of colors used. Thus, it

would be desirable to use a large number of colors to embed

more information in the same barcode.The main problem with using many colors in a barcode is

that the observed surface color depends not only on the sur-face reflectance spectrum, but also on the

(unknown) illumi-nant spectrum, which thus represents a nuisance parameter.Consequently,

determining the color index of each surface patch in the barcode is a challenging operation, especially

if multiple light conditions (indoor/outdoor) are expected. Other nuisance parameters include:

specularities; color drift during printing; color fading; unknown or poorly calibrated

7/30/2019 COLOR 2D

15/24

camera color response; camera non-linearity; color mix-ing from two nearby patches due to blur;

quantization and noise.

ColorCode

Perhaps the first reported attempt to use color in a 2-D barcode can be found in a patent by Han et al.

[8], who used reference cells to pro-vide standard colors for correct indexing. This technology, named

ColorCode , is marketed by Colorzip Media (col-orzip.com).

Developed by researchers at Korea's Yonsei University, ColorCode is a proprietary two-dimensional bar code system that is designed to store URLs and be read by a cell phone camera.

It allows a camera to recognize indexed codes, which are in turn linked to data. The matrix of

blocks and analog data pertaining to the number of colors are digitized and then processed by a

dedicated server using addresses registered for the codes. More information is available at

ColorZip SEA Pte Ltd. Also see United States patents:6,981,644,7,020,327, and7,487,914.

Data Glyph

PARC DataGlyphs are a robust and unobtrusive method of embedding computer-readable dataon a variety of surfaces.

Unlike most barcodes, DataGlyphs are flexible in shape and size. Their structure and robusterror correction also make them suitable for curved surfaces and other situations where barcodes

fail.

Basic DataGlyphs/Microglyphs are a pattern of forward and backward slashes representing ones and zeroes. This pattern forms an evenly textured field.

Features

1. Flexibility - adjustable size, shape, color2. High data density3. Robustness4. Adjustable error correction5. Compatible with cryptography

At 600dpi, DataGlyphs/Microglyphs offer up to 1KB per square inch of data. At this density, theGettysburg Address fits in a block the size of a small United States postage stamp.

Applications:

http://colorcode.com.sg/http://colorcode.com.sg/http://www.adams1.com/patents/US6981644.pdfhttp://www.adams1.com/patents/US6981644.pdfhttp://www.adams1.com/patents/US6981644.pdfhttp://www.adams1.com/patents/US7020327.pdfhttp://www.adams1.com/patents/US7020327.pdfhttp://www.adams1.com/patents/US7020327.pdfhttp://www.adams1.com/patents/US7487914.pdfhttp://www.adams1.com/patents/US7487914.pdfhttp://www.adams1.com/patents/US7487914.pdfhttp://www.adams1.com/patents/US7487914.pdfhttp://www.adams1.com/patents/US7020327.pdfhttp://www.adams1.com/patents/US6981644.pdfhttp://colorcode.com.sg/

7/30/2019 COLOR 2D

16/24

1. document management2. fraud prevention3. inventory tracking4. ID cards5. parts marking6.

product tagging

A different type of color barcodes [14] is mar-keted by ImageId (imageid.com). Bulan et al. [3] proposed

to embed data in two different printer colorant channels via

halftone-dot orientation modulation. Grillo et al. [7] used 4

or 16 colors in a regular QR code. PM codes [16] use color

to define layers, each of which makes up a 2-D barcode.

Kato et al. [9] select colors that are maximally separated

in a plane of the RGB color cube. The same type of color

barcode (named MMCC) was used in a study the effect of

JPEG compression on decoding [15]. Pei et al. used four

colors in a color barcode technology named Continuous

Color Barcode Symbols *13+.

None of these previous works tried to model the changes

of the observed color due to changing illuminant, except

for the patent of Sali and Lax [14], which uses a k-means

classifier to assign the (R,G,B) value of a color patch to

one reference color. Note that existing color constancy al-gorithms (e.g.[10, 6, 5, 4, 2]) are not of much

use here.

Classic color constancy assumes that neither the surface

7/30/2019 COLOR 2D

17/24

reflectance nor the illumination are known a priori, and

High Capacity Color Barcode (HCCB) technology [12]

uses 2-D barcodes enhanced with four or eight different

colors. This technology, marketed as Microsoft Tag

(tag.microsoft.com), is becoming increasingly widespread

in applications such as retail, publishing, and transit.While

HCCB may be used for a variety of applications, its most

immediate application is for marking univoquely commercial

medias such as motion pictures, video games, broadcasts,

digital video recordings, etc... We now describe briefly the

main features of HCCB (see Figure 4). It consists of rows of

strings of symbols (triangles) of four different colors: black,

red, green and yellow, and consecutive rows are separated by

a white line. While the number of rows in a HCCB code

may vary, the number of modules in each row is always a

multiple of the number of rows. A module represents the basic

entity for storing information in a 2D code. HCCB has a black

boundary around it, further surrounded by a thick white band.

These patterns are designed to act as visual landmarks in order

to locate the barcode in an image. The black boundary at

the bottom of HCCB is thicker than the boundaries on the

other three sides: the bottom boundary acts as an orientation

7/30/2019 COLOR 2D

18/24

landmark, as barcodes may be at an arbitrary orientation in

the image. The last 8 symbols on the last row are always in

the fixed order of black, red, green and yellow (2 symbols per

color) and can be used as a color palette during the scan.

This paper provided a complete scheme allowing locating and reading bar codes with a 2D

vision system. It is composed of two main functions: bar code localization on the overall

image, and the reading stage. The localization of the symbol, which can be oriented in any

direction, is carried out with an original method, which relies upon the extraction of high-density

area of mono-oriented gradients. The reading method is based on the detection of the

transitions between the stripes by extracting the zero-crossings of the second derivative of the

ID signal reconstructed from the 2D bar code block.

In this paper, we propose Color Quick Response Code or CQR

Code for short, which is a Matrix code that has been extended into

a 3D barcode system. Matrix code itself is a 2-dimensional

barcode that appears to be a 2D image that consists of usually

black and white dots that can be printed or displayed on a screen.

CQR Code is an extended version of the popular QR Code. 3D

barcodes contains data not only in its x and y axis, but also in

depth. By stacking QR Codes we can create a new barcode system

that can store more data than other existing barcode systems.

Through this barcode system, we can embed data that normally

7/30/2019 COLOR 2D

19/24

could not be done using existing barcode systems.

From the tests that had been conducted, currently the CQR Code

is capable of storing data up to 9KB with 3 layers and 8 colors.

The CQR Code can be read with 40% - 100% chance of success

using a multi-format mobile phone barcode reader prototype. We

have also implemented a simple color correction algorithm into

the barcode reader to ensure its accuracy.

In conclusion, CQR Code has the potential for future

developments for it to be a simple, sophisticated, and easy to use

barcode system that can store relatively large amounts of data.

In paper, an extended version of the popular QR Code known as Color Quick Response Code( CQR )

is described that contains data not only in its x and y axis, but also in

depth. This paper shows that by implementing color patterns (instead of just black and white), utilizing

mobile phone cameras, and data compression, more data can be added into the matrix code.

paper also contains procedures to encode a CQR Code and also procedures to read it using a mobile

phone barcode reader application. By stacking the QR Codes a new barcode is created that is capable

of storing data up to 9KB with 3 layers and 8 colors. CQR Code can be utilized for mass mobile content

distribution and can be integrated with printed media. The data capacity can be improved by adding

more layers into the barcode system A better color correction algorithm can be implemented to

improve barcode reader accuracy and for tackling the problem of discoloration and color changes of the

color barcode by external factors.

HCC2D

Bulan et al. [3] proposed

7/30/2019 COLOR 2D

20/24

to embed data in two different printer colorant channels via

halftone-dot orientation modulation. Grillo et al. [7] used 4

or 16 colors in a regular QR code.

The contribution of this work is a new 2D code technology,

named HCC2D (High Capacity Colored Two Dimensional),

which use colors to increase the code data density. The intro-duction and recognition of colored

modules in HCC2D poses

some new and non-trivial computer vision challenges, such

as handling the color distortions introduce by the hardware

equipment that realizes the Print&Scan process. The HCC2D

codes presented in this paper are able to support different

types and sizes of data input, and adapt smoothly the code

dimension to the actual input size. In order to support all

those scenarios in which the Print&Scan process imposes

the usage of only two colors (i.e., Black&White) HCC2D

considers Black&White codes as codes with exactly two

colors. In particular, HCC2D has been designed so as to be

fully compatible with the standard QR code, which is currently

the most widespread 2D code technology (a standard QR code

represents the simplest case of our 2D colored code). The main

advantage of HCC2D over QR is that HCC2D is able to store

substantially more data than QR, while preserving the strong

7/30/2019 COLOR 2D

21/24

reliability and robustness properties of QR.

The main goals of our HCC2D code are to increase the

space available for data and to preserve strong robustness and

error correction properties similar to the original QR standard.

HCC2D increases the storage space by generating each module

of the data area with a color selected from a color palette.

Figure 7 illustrates samples of HCC2D with 4 colors HCC2D

Kato et al. [9] select colors that are maximally separated

in a plane of the RGB color cube. The same type of color

barcode (named MMCC) was used in a study the effect of

JPEG compression on decoding. In this

paper, we present the challenges faced by the use of colours in 2D

barcodes for mobile devices. We also introduce a novel colour

selection scheme for 2D barcode, which is implemented in our

novel colour 2D barcode - the MMCCTM. Our novel selection

scheme resulted in a robust 2D barcode that can use more colours

than existing colour 2D barcodes for mobile devices. CHALLENGES OF A COLOUR ENCODING SCHEME

Despite the potential of using colour to increase the data

capacity of barcodes, most researchers/developers prefer to

develop monochromatic 2D barcodes. This is because the use

7/30/2019 COLOR 2D

22/24

of a greater multitude of colours introduces problems that

negatively affect the robustness of barcode reading. First of all,

colours are more susceptible than their monochromatic

counterparts to external effects. For example, a colour image

can be reproduced differently from its original colour,

depending on the image capturing and processing devices (e.g.

scanner, digital camera and web camera) [2], the printing

devices used and/or the quality of papers where the image is

printed.

Lighting conditions can also have a great impact on the

colour value of captured images [2], [3]. In fact, lighting is the

primary factor to be considered when using colours. The

gamma correction or white balance might be automatically

performed by the built-in camera of mobile phones so as to

minimise the lighting effect and produce better images.

However, what is performed by these cameras is greatly

dependent on the Charge Coupled Device (CCD) or

Complementary Metal-Oxide Semiconductor (CMOS) sensor

used [4].

The factor inherent in colours also has a significant effect on

the robustness of barcode reading. A particular colour is often

identified within a colour space. Increasing the number of

7/30/2019 COLOR 2D

23/24

colours to encode data reduces the distance between colours in

a given colour space, making it difficult to distinguish each

colour robustly. To ensure the robustness of barcode reading,

the colours that are furthest apart in a particular colour space

are usually selected for encoding data into colour symbols or

cells. However, it is inevitable that the use of more colours

reduces the distances between the neighbouring colours.

performed by the built-in camera of mobile phones so as to

minimise the lighting effect and produce better images.

However, what is performed by these cameras is greatly

dependent on the Charge Coupled Device (CCD) or

Complementary Metal-Oxide Semiconductor (CMOS) sensor

used [4].

The factor inherent in colours also has a significant effect on

the robustness of barcode reading. A particular colour is often

identified within a colour space. Increasing the number of

colours to encode data reduces the distance between colours in

a given colour space, making it difficult to distinguish each

colour robustly. To ensure the robustness of barcode reading,

the colours that are furthest apart in a particular colour space

are usually selected for encoding data into colour symbols or

cells. However, it is inevitable that the use of more colours

7/30/2019 COLOR 2D

24/24

reduces the distances between the neighbouring colours.

we have proposed a novel colour selection scheme that overcomes some of the challenges

encountered in using more colours for 2D barcodes. Our novel

scheme has resulted in the design of a novel colour 2D barcode,

which is a robust and fault tolerant barcode using more colours

than any existing colour 2D barcode for mobile devices.