Chapter 6 ( How to write a report )

Computer systems computer systems

 Topic: scanners

Abstract

• Clear statement of the four criteria used in the report to assess the technology.
• Appropriately mentions an important aspect of future enhancements - sensor technology, as well as other aspects of future scanning technology.
• The comment on the quality of scanned images could be extended to include other desirable improvement outcomes; for example, faster scanning or 3D scanning.

      This report investigates the current state of scanner technology and examines the predicted future advancements of scanners. A brief history of the scanner and its operation is initially outlined. The discussion then focuses on the advantages and limitations of the five main types of scanners in common use today: drum, flatbed, sheet-fed, slide, and hand held scanners. The performance of these scanners is examined in relation to four main criteria: resolution, bit-depth, dynamic range and software. It is concluded that further technological advances in these four areas as well as the deployment of new sensor technology will continue to improve the quality of scanned images. It is also suggested that specialised scanners will increasingly be incorporated into other types of technology such as digital cameras.
Introduction
    The purpose of this report is to survey the current state of scanner technology and to briefly discuss predicted advancements in the field.
By examining a range of recently published journal articles, magazine articles and internet sites on the topic of scanners this report describes the main types of scanners in common use today and examines their performance in relation to four criteria: resolution, bit-depth, dynamic range and software. The report then considers the effect of further technological advances in these four areas, as well as the deployment of new sensor technology on the future development of scanners.
The first scanner, initially referred to as a 'reading machine', was developed in 1960 by Jacob Rabinow, a Russian born engineer. The device could scan printed material and then compare each character to a set of standards in a matrix using, for the first time, the "best match principle" to determine the original message (Blatner, Fleishman and Roth 1998, p.3). This reading machine was to form the basis for the development of current scanning, sorting and processing machines.
Body
    A scanner is a device that uses a light source to electronically convert an image into binary data (0s and 1s). This binary data can then be used to store the scanned image on a computer. A scanner recreates an image by using small electronic components referred to as the scanner's 'eyes' (Scanner tips 2000). The type of 'eyes' used in today's scanners are charge-coupled devices (CCD) and photomultiplier tubes (PMT). These electronic eyes measure the amount of light reflected from individual points on the page and translate it to digital signals that correspond to the brightness of each point (Englander 2000).
To create a file on the computer that represents a colour image, the scanner divides the image into a grid with many individual points called pixels or picture elements (Scanner tips 2000). A scanning head, termed a row of 'eyes', reads over the grid and assigns a number to each pixel based on the main colour in that pixel, using green, blue and red. For example an aqua pixel would be saved as a number to represent the proportion of blue, green and red which represents the colour aqua (Scanners, digital cameras and photo CDs 2000).
    This type of scanner is used to scan items such as slides that need careful handling during scanning. Unlike other scanners, the scanning heads in slide scanners do not reflect light from the image, but rather pass light through it. This enables these scanners to produce superior results without distortions caused by reflective light. To be able to scan small and detailed items, these scanners have a large number of eyes on the scanning head which produces a high quality result. Slide scanners tend to be more expensive and less versatile than flatbed and sheet-fed scanners as they are limited to only scanning slides and film. These scanners, however, are well suited to users requiring high quality scans of large numbers of slides (Scanner tips 2000).
Conclusion
    This report has identified five types of scanners currently available. Some are primarily used for professional purposes such as the drum scanner; others are used more broadly in the workplace and home such as flatbed scanners and to a lesser extent sheetfed scanners. Scanners for specialized purposes have also been identified such as slide and handheld scanners. The performance of these scanners is dependent upon their resolution, bit-depth, dynamic range and software. Scanners have improved significantly in recent years in terms of weight, size, price and speed, and the replacement of CCD technology with CIS technology is anticipated to produce further benefits to these areas as well as to scan quality. The impact of these improvements is expected to increase the accessibility of scanner technology to a wider range of users and its suitability for a wider range of purposes. In relation to this, the future of scanner technology seems to point to the convergence of different technologies. Specialized scanners are currently being incorporated into other types of technologies such as digital cameras, printers, and photocopiers. This can be expected to continue with other forms of technology in conjunction with further improvements to image quality, speed, price, size and weight.
Reference list
Anderson, D. The PC Guide. [http:www.pctechguide.com/18scanners.htm].
Blatner, D., Fleishman, G. Roth, G. (1998) Real world scanning and halftones 2nd edition, Peachpit Press, USA.
Englander, I (2000). The Architecture of computer hardware and systems software. John Wiley, USA, p272.
Figeiredo, J. McIllree, J. Thomas, N. (1996) Introducing information technology 2nd edition Jacaranda Press, Singapore, p145.

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