Week 6 FYP1

Week 6

Date: 21-25/10/2013 (Monday to Friday)

Title: Research and findings

This week, the research continues on focusing about the barcode scanner. The research focusing on what type of barcode scanner and how it works.

Summarize of my research :

A barcode reader (or barcode scanner) is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones. Additionally, nearly all barcode readers contain decoder circuitry analyzing the barcode's image data provided by the sensor and sending the barcode's content to the scanner's output port.

For UPC barcodes, the barcode scanners that can scanned it are the pen-type scanner and the laser-type scanner.

Pen-type scanner

Pen-type readers consist of a light source and photodiode that are placed next to each other in the tip of a pen or wand. To read a bar code, the person holding the pen must move the tip of it across the bars at a relatively uniform speed. The photodiode measures the intensity of the light reflected back from the light source as the tip crosses each bar and space in the printed code. The photodiode generates a waveform that is used to measure the widths of the bars and spaces in the bar code. Dark bars in the bar code absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is a representation of the bar and space pattern in the bar code. This waveform is decoded by the scanner in a manner similar to the way Morse code dots and dashes are decoded.

Laser scanner

Laser scanners work the same way as pen type readers except that they use a laser beam as the light source and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the bar code. As with the pen type reader, a photodiode is used to measure the intensity of the light reflected back from the bar code. In both pen readers and laser scanners, the light emitted by the reader is rapidly varied in brightness with a data pattern and the photodiode receive circuitry is designed to detect only signals with the same modulated pattern.

For QR code, the scanner that can be used are the camera-based scanner and the camera on the smartphone.

Camera-based scanner

Camera-based scanner is a scanner that can read 2D barcodes (QR code). It uses t a camera and image processing techniques to decode the barcode.

Camera on smartphone

This technique is widely used around the world to decode the QR code. There are a lot of phone application that are available that can be used to decode the information in the QR code.

There are also some barcode scanner that can scan both UPC and QRC. For an example is the Motorola DS4208.