Appendix D - Calculating Code Size and Capacity

The code stamp size and the data capacity are influenced by the print media and the dpi (dots per inch) capability of the printer used.

The data in a 2D barcode is rendered as groups of modules. A module contains one or more dots and is equivalent to Binary 1. The residual white space in the code is treated as a Binary 0. The interplay between the black and white areas allows the meaning of the pattern to be referenced as data.

For the matrix code types of QR Code and DataMatrix, each black area or module is recommended to comprise of 4 or more dots to maximize the stability of the code stamp. The overall size of the stamp is then constrained by the printer head and the number of dots in a module, this relationship is detailed below.



The module size will then directly impact the overall size of the barcode stamp depending on the capacity required.

Carl Sewell has a spreadsheet that shows the relationship between barcode proportions (rows and columns) , the data capacity (Numeric, Alphanumeric and ASCII) and the stamp size in inches for the DataMatrix format,

B2C

The largest opportunity for the adoption of 2D barcodes will be within the B2C segment through the distribution of tickets and promotional coupons, generically referred to as vouchers.

Vouchers

These can be earned through paying for a service or by receiving a coupon for a free item, for example a coffee from your nearest Starbucks.

Air New Zealand has already adopted the use of 2D barcodes, specifically the PDF417 format, as a key enabler of their self service check-in solution. This approach could easily be transcribed to adjunct service providers as a means of distributing tickets to customers.

By applying a different format that can be easily presented from a mobile phone screen to an appropriate barcode reader, TicketMaster could transform the purchase, distribution and admission process for venue events for example; concerts, sporting events, trade shows and cinemas.


Similarly businesses that wish to reward customers with free products or merchandise through a promotion, typically be sending coupons, could utilise 2D barcodes to revolutionise this form of marketing campaign.

A coffee franchise could adopt 2D barcodes in the following process. First, send the coupon in the form of a matrix code to a known customer as an SMS or MMS. On receiving the electronic message, the customer can then present the coupon on their mobile handset. The square, compact nature of matrix codes such as QR Code or DataMatrix, lends itself to the size and proportiions of the average mobile phone screen. This is not the case for traditional linear barcodes. The data capacity of 2D barcodes gives the franchisee greater flexibility in tailoring coupon content. It is therefore possible to achieve personalised coupons that contain coffee choice, member information and location data in a very compact and portable coupon form.

Another example: Dynamic Advertisement

Matrix Codes

The most established form is the matrix code that uses vertical and horizontal grid of pixels to encode data.  Forms of matrix codes inlcude:

• QR Code - Quick Response codes, the most successful form of matrix code widely adoptied in Japan.
• PDF417 - a stacked barcode commonly used by airlines for eTicket presentation.
• DataMatrix - a similar form to QR Code widely used in USA.

Basic Characteristics

Our research has identified two main forms of 2D barcodes - Matrix Codes and Radial (Polar Coordinate) Codes.

• Matrix Codes
• Radial Codes

One of the key differentiators for the use of 2D barcodes is the data capacity they offer.  Due to the use of both horizontal and vertical axes, the data can be stored in a much smaller area when compared to traditional barcodes, like those used in shops.  The table shows potential data capacity and usage options for five of the main symbologies.

The actual data capacity of a 2D barcode is dependent on a number of factors.  These include the media choice, the final size of the presentation allowing for the resolution of the dots used in the printing process (Appendix D) and the level of error correction required (Appendix E).

With the higher data capacities available in 2D barcodes, a number of different types of message can be encoded in the barcode.  This allows for a wide range of potential uses, though the intepretation of the message is generally dependent on the capabilities of the reader.

The different message types allow for different modes of operation for publishers and subscribers of 2D barcodes.  These are a choice of a push mode or a pull mode.

Introduction

This online report discusses the potential use of 2-Dimensional (2D) Barcodes within New Zealand.  This is an applied use of a common piece of technology, the mobile phone camera, that takes data in the form of a binary image and turns it into information.

One version of this application has been in active use in Japan sunce 1995 and has evolved from a way of tracking car parts to mobile tagging where information is now quickly and easily retrieved by most current Japanese mobile phone (Appendix A).

The report will outline the basic characteristics of this evolution of tradtional barcodes, the types of industries and ways that these industries could use 2D barcodes and finally any issues and barriers to the form adoption of this technology.

The barcode has evolved from the one dimensional form widely adopted in the retail industry since the 1950's to the current forms of 2D barcodes now in circulation and being applied to diverse industries outside of retail.  This evolution has resulted in higher data capacity and greater flexibility of use, all in a smaller presentation area.

Why use 2D Barcodes?