Automatic identification systems (Auto-ID) have become an attractive solution in a wide range of customer-oriented industries, logistics and supply chain management, fabrication and processing of products from raw materials. The Auto-ID aim is to provide information about people, animals, assets and products being processed [11].
The widely used barcode labels started the revolution in automatic identification systems in the 1980s, however nowadays are being found insufficient for an increasing number of applications. Barcodes are very cheap, but they reading distance is limited to a few centimeters, require direct line-of-sight (LOS) to be read and they can’t be reprogrammed [11].
The use of ICs to store the data would be the technical optimal solution to overcome the barcode disadvantages. The smart card is the most used type of electronic data- carrying appliance (bank cards, library cards, personal identification cards, etc.), it is based on a contact field that requires mechanical contact with the reader, which also
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makes it often quite impractical. Therefore, the need to implement a contactless system to transfer data between the data-carrying device and its reader becomes obvious, and in an ideal case, the power needed to operate the electronic data-carrying device should also be transferred from the reader using contactless technology. The Auto-ID system that uses radio waves to contactless transfer power and data is the RFID system [11].
The following subsections provide a brief introduction to different Auto-ID systems.
2.1.1 Barcode Technology
The barcode is a binary representation of data and is the most used technology for identification of products, with billions of daily scans all over the world. There are two main types of barcodes currently being used: one-dimensional (1D) and the two- dimensional (2D) barcode. The 1D barcode is the most popular and it consists of a set of bars and gaps arranged in a parallel configuration. The data representation takes place by varying the widths and spacing between bars according to a predeterminate pattern. The barcode is read by optical laser scanning, e.g. by calculating the difference in the reflection of a laser beam from black bars and white gaps, the European article number EAN-13, which is the most used standard, encodes 13 digits. The 2D barcode on the other hand, such as the quick response (QR) codes, encodes the data in both horizontal and vertical dimensions increasing the capacity, the model 2 with 177 × 177 modules can store up to 7,089 digits, it has recently been gaining more market, especially due to the advancement of the smartphone technology, where the barcodes can be capture by the device’s integrated camera and the message extracted using a mobile application [11] [12] [13] [14].
2.1.2 Optical Character Recognition
The optical character recognition system (OCR) was first used by companies in the 1960s. Its aim was to convert printed text to machine-encoded text, therefore, special fonts with stylized characters were developed in a way that they could be read both by
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the human eye as well as automatically by the OCR reader. Allowing to have high density information and in case of an emergency, be able to read the data visually [11].
Although OCR system failed to become universally applicable due to the development of its complicated reader, which at the time increased its price when compare to other Auto-ID products [11]. Nowadays, as the processing capabilities of mobile/wearable devices increases and are being equipped with high resolution cameras and microprocessors, the OCR has become feasible, attractive and ubiquitously available using sources like scanned documents, digital photographs, business cards, etc. to obtain information [15].
2.1.3 Biometric Procedures
The biometric procedures involve measuring of physical characteristics of living beings, that is, identifying people by comparing unmistakable its individual characteristics like fingerprints, voice, retina or iris [11].
2.1.4 Smart Cards
A smart card is a system where the data is stored electronically, in some cases with additional processing capacity like a microprocessor card. It comes in a plastic card of the same size as a credit card (85.60 mm × 53.98 mm). The smart card is read by placing it in the reader, where the card’s contact springs make a galvanic connection with the respective set in the reader. The data transfer takes place using a bi-directional serial interface. Two different type of cards could be found: the memory card and the microprocessor one [11].
The information in the memory card is accessed using a state machine, they can be cost effective for some type of applications and that is why they are predominantly used in price sensitive, large-scale applications [11].
The microprocessor cards contain a microprocessor connected to a segmented memory: read-only memory (ROM), random access memory (RAM) and electrically erasable programmable read-only memory (EEPROM). The ROM and its content are inserted during the manufacturing of the integrated circuit. The EEPROM contains the
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application data, the operation system allows the reading or writing of data to this memory [11], and the RAM is the microprocessors temporary working memory. The data stored in the RAM is lost after the smart card is disconnected from its supply voltage [11].
Microprocessor cards are mainly being used in security sensitive applications like banking e.g. EC-cards (electronic cash) [11].
2.1.5 RFID Systems
The RFID systems stored the data in an electronic data-carrying device, namely the transponder. The power supply as well as the data transfer between transponder and reader is achieved by means of electromagnetic fields. Due to the advantages of the RFID systems compared to other Auto-ID systems, RFID Systems are currently being developed to overcome new mass markets like item level tagging. The working principle taken from the fields of radio and radar engineering, will be explained further in the next section [11].