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Presented on September 23, 2010


Scanning Technology

This brief paper discusses the basics of scanning technology, its history and development, related technologies, significance, and its place in the future.


The process of converting data into computer format is by digitizing them, and the way in which graphics are digitized is by scanning. According to Online Technology Learning Centre (2002), scanning “is the process of transforming a physical media into a digital file and then formatting that file so that it can be read by a computer application.” The physical media can be items such as a photograph, small objects, text, or even a document in the form of paper etc. It can therefore be deduced that scanning is also the process of converting files, images, and data into easily accessible, retrievable, and searchable electronic formats. WordNet defined scanning “the process of translating photographs into a digital form that can be recognized by a computer,” or “as the act of systematically moving a finely focused beam of light or electrons over a surface in order to produce an image of it for analysis or transmission.”

As a means of converting data into a computer format, scanning of documents and images is usually carried out using a scanner. Scanner, often referred to as image scanner is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image, (Wikipedia).

Scanning modes and preferences

Common scanning modes and preferences a user can employ or choose from when scanning documents and images are Line Art, Greyscale, and Colour scanning. However, the scanning preference to be used is largely dependent on the type of document or image a user wants to scan. Line Art - this preference is often used when the graphic is black and white, without an identifiable shade of gray. The line art is relevant for sketches, cartoons, blueprints, diagrams, black and white logos. When the image or file scanned is in black and white in line art, lots of space is saved. This is primarily because a pixel can only be black or white; as a result, the computer doesn't need to store lots of colour information. This means that the higher the colour, the more space consumed.

Greyscale - when graphic has shades of grey as well as black and white, grey scale is usually the appropriate preference to be used in the scanning process. Greyscale scanning records up to 256 shades of grey, and so the transition from white to black is smooth. Because of these varying shades of grey in the greyscale preference, scanned images are much bigger than those of the line art.

Colour - colour preference is normally used when scanning a colour graphic, photograph, image, and document. In scanning colour images, each pixel stores one of millions of different colours. As a result, coloured scans occupy most space in the storage device, (Virtual Training Help Centre, 2002).

Scanning resolution

The type of selected scanning resolution determines the quality of images, texts, and documents when they have been processed. Virtual Online Help Centre (2002) defined resolution as ‘a measure of how clear and sharp an image is’. Scanning resolution is measured in dots per inch (dpi). A dot per inch is a printer resolution (hard copy format). In the digital world, the appropriate term used is pixels per inch (ppi), but the term dpi has been adopted by many people to represent digital resolution, even though dpi and ppi are used interchangeably. [1] Virtual Online Help Centre (2002) identified that when a scanner scans a graphic or a digital camera takes a picture, the image is stored as a pattern of discrete dots. Each dot stores information about the graphic, which results to the increase of the dots. As the dots increases, the inch also increases; therefore, the more information stored, the more the image file.

The type of scanning resolution to be used is largely dependent upon what a user plan to use the scanned image for. Virtual Online Help Centre (2002) highlighted some rough guidelines for choosing a scanner resolution.

72-100 dpi for images that will be viewed on a computer screen (e.g., web graphics); 250-300 dpi for images that will be printed on an ordinary inkjet or laser printer; 600 for a very high-quality printer or for commercial printing; 300-600 (or more) if you want to enlarge or edit the image; 600 or higher for archiving for future use (a user can reduce the resolution at a later time, but cannot add any resolution).

Colour depth

When scanning an image, colour depth or bit depth is used to select or to represent the colour of a single pixel in a bitmapped image or video frame buffer. Unlike scanning resolution which is in dpi or ppi, colour depth is calculated in bits per pixel (bpp) (Wikipedia). Using a high colour depth provides large range of several different colours. In the course of scanning an image, bits increases and the number of colours becomes too large for a colour map. So in higher colour depths, the colour value typically directly encodes brightness of red, green, and blue to specify a colour in the RGB model. However, the RGB colour model is a colour model in which red, green, and blue light are added together in various ways to reproduce a broad array of colours. The term RGB is derived from the initials of the three additive primary colours of red, green, and blue. Its main function is for the sensing, representation, and display of images in electronic systems, such as televisions, computers, conventional photography, and can also be used in scanning images.

There are different bit colours identified by Wikipedia. The following are predominantly used when scanning texts, images, and documents with a scanner:

1-bit monochrome (black and white of 2 colours); 8-bit greyscale (4 colours); 8-bit colour (256 colours); 12 bit colour (4096 colours); 15/16-bit colour (High Colour of 65,536 colours); 24-bit colour (True Colour of about 16,777,216 mixed colours); 32-bit colour (Deep colour of about 4.2 billion distinct colours);

There are other types of colours available, but are specifically for high level graphics and computer workstations, as well as industrial uses. These colours include 36-48 bit colours, which are also deep colour like the 32 bit.

Types of scanner

There are several types of scanner but the following scanners identified by Wikipedia can suffice:

Drum Scanner: The drum scanners make use of the Photomultiplier Tubes (PMT), to capture the images. Photomultiplier tubes (PMT), are sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. Reflective originals are placed on an acrylic cylinder, the scanner drum, rotating at a high speed while it moves, scans the object in front of precision optics that deliver image information to the PMTs. Drum scanners have capacity to reproduce scans that are of high quality in resolution, color depth, and value structure. More so, because drum scanners are capable of producing resolutions of up to 12,000 pixels per inch (PPI), they are usually used for enlarging images during scanning processes. The origin of the name drum scanner was from the clear acrylic cylinder, the drum, on which the original artwork is mounted for scanning documents and images. File:Drum Scanner II.jpg Drum Scanner

Flatbed scanner: This is composed of a glass pane (or platen), under which there is a bright light (often xenon or cold cathode fluorescent) which illuminates the pane, and a moving optical array in CCD scanning.

File:Flat-Bed Image Scanner II.jpg Flat-Bed Scanner

Hand scanners: these come in two forms of document and 3D scanners. Hand held document scanners are manual devices that are dragged across the surface of the image to be scanned. Normal hand held scanners have a small window for viewing the document being scanned. Though use of handheld scanner is gradually running out, 3D scanners are more popular in industrial design, reverse engineering, inspection & analysis, digital manufacturing and medical applications.

File:Hand Scanner.jpg Hand Scanner


Scanning provides varying benefits to man today. Basically, with electronic document imaging, any type of documents are scanned, captured, and processed automatically. Basic significance of this technology is the efficiency which it provides to man, his environment, and businesses in the ever-evolving and increasing demand in information and communication technologies (ICTs). Furthermore, the following listed, but briefly explained significance of scanning technology cannot be overlooked:

Improved customer service – With the advent of scanners, customer services in organizations has improved because scanned documents, images, texts, and photographs can be easily reached and provided for users benefit. In libraries for instance, the reference and reprographic services section provides efficient and effective service to its clientele by retrieving scanned books, newspapers, and magazines at a faster rate.

Enable creation of text editable, searchable, and retrievable electronic files – Documents, images, and photographs can be searched, retrieved, and edited. Once a document has been scanned, its quality (especially resolution and colour depth) can be changed and also improved to sooth the user’s desire and purpose. Scanned documents can be easily arranged and stored in files and folders on a computer in alphabetical or chronological order.

Enable electronic archive, management, and distribution of important documents – Scanned documents can be electronically archived and stored away for years, and can also be retrieved for re-distribution.

Immigration purposes – Most organizations including governments and non-governmental organizations have introduced use of biometric information for easy identification of its personnel, individuals, and citizens. For governments, its importance includes using finger-print scanner to super-emboss finger-print details of individuals on passports along with the bio-data. With this new technology, switching of passports cannot be possible, while tracking of terrorists becomes easier, because biometric data of an individual cannot have a semblance or be identical with someone else.

Creates cost effectiveness and space – Electronic Imaging Systems (2007) stated that electronic imaging of documents provides solutions and services designed to reduce costs and improve productivity of organization for customer satisfaction. Cost of printing papers, postage, and miscellaneous services becomes limited because documents, images, photographs are now scanned stored away for several uses. Large amount of scanned files and documents can be sent to long distances (including the space) through emails thereby eliminating the costs of printing and mailing. In offices, piles of files and documents that usually occupy space is now a thing of history, because documents are scanned and stored on disks for easy retrieval.

Finally, similar to the above stated significance, Xerox (1999) identified that the power of scanning technology ensures document security and accessibility, increases productivity in organizations, speeds-up business processes, and as well as reduces operating costs for businesses and organizations.


The origin of scanning can be traced to Paul Nipkow, who in 1884 patented his image scanning machine. It was to use a rotating disk with a series of holes arranged in a spiral, each spaced from the next by the width of the image; a beam of light shining through the holes would illuminate each line of the image, (ThinkQuest).

Present day scanners are outgrowth of early telephotography devices which consists of rotating drum with a single photo detector. These are similar to the drum scanner developed by Russell A. Kirsch in 1957 at the United States National Bureau of Standards (USNBS). He invented the drum scanner which operated on telephotography technique, with components such as rotating drums. The drums had a photo detector attached to them, rotated at 60 or 120 rotations per minute (rpm) speed (Wikipedia). Later models of the scanner rotate at a standard speed of up to 240 rpm. However, these scanners send linear analogue AM signal through the normal telephone voice lines to receptors, after which, a special paper is used to print images. These models of scanners were in operation up to the middle of 1990’s before the development of modern day scanners.

Furthermore, the first image scanner developed for computer processing was the drum scanner, which was used to scan the first image. The image was that of Russell Kirsch’s three month old son, Walden. The image was scanned in a black and white resolution of 176 pixels.

Related technology

3D scanner is a device used to collect data of an object shape and appearance. The data can further be used to design 3D models for numerous uses in the entertainment industry, for movie production, video games, industrial designing, reverse engineering and prototyping, quality control and inspection of cultural artifacts, etc. The main aim of 3D scanner is basically to create geometric samples on the surface of the object being scanned. In order to produce a 3D model, the lidar scanner may be used to scan buildings, rock formations, etc. The lidar scanners aims its laser beam in a wide range with its head rotating horizontally, a mirror flips vertically and scans the object, (Wikipedia).

File:3D Scanner.jpg

Biometric scanning is one of the recent advanced scanning technologies available. Spinella, 2003 stated that it is a scanning technology developed for measuring and analyzing personal characteristics of both physiological and behavioural state of individuals. This technology includes fingerprints, voice patterns, hand measurements, irises, and others for verifying human identities. One specific advantage of the biometric technology is that personal unique identities of one individual cannot be stolen neither will it be used to represent another, other than the particular individual. Spinella, 2003 further indicated that given the problem solving nature of the technology, more and more organizations continue to adopt it for security check, access control, fraud and theft in their businesses.



Considering the continuous growth and development of technologies in the contemporary society, demands for new technologies continue to be on the rise, and as such, the future and development of scanning technology cannot be neglected. Today, the technology is in high demand and is applied in a wide variety of spheres, ranging from individuals, organizations, governments, to technological inventions and innovations, medicine, building technology, oil, and gas industries, etc. Therefore, newer models with high capacities and of good quality will continue to emerge from manufacturing industries such as HP, Canon, Xerox, and the more. Research and development (R&D) will continue to advance the production of this technology for industrial, commercial, and individual uses. Xerox and many other companies, has a multifunction machines for creating digital copies of any document that can be easily archived, stored, shared, retrieved, emailed, faxed or printed.


Scanning is very important in our everyday businesses and lives. Digital images, document files, and pictures can be scanned and sent across long distances via email, which is cost effective rather than posting them via regular mails. Before the advent of digital cameras, scanners were considered highly important because of the role they played to individuals and organizations. Still, its importance in the contemporary and ever-evolving society cannot be neglected.


[Electronic Imaging Systems (2007). Retrieved 23 September, 2010 at]

[Online Technology Learning Centre (2002). Tuscaloosa City Schools. “Scanners and scanning”. Retrieved 22 September, 2010 at]

[Spinella E, (2002). “Biometric scanning technologies: finger, facial and retinal scanning”. SANS Institute - InfoSec Reading Room. Retrieved 23 September 2010 at]

[ThinkQuest. “Paul Nipkow: co-invented the television”. Projects by Students for Students Retrieved 23 September 2010 at]

[Virtual Training Help Centre (2002). Bloomberg University. “Digital images”. Retrieved 22 September, 2010 at]

[Wikipedia. “Colour depth”. Retrieved 22 September, 2010 at]

[Wikipedia. “Image scanner”. Retrieved 24 September, 2010 at]

[Wikipedia. “RGB colour models”. Retrieved 30 September, 2010 at]

[WordNet. “Scanning”. Princeton University. Retrieved 22 September, 2010 at]

[Xerox, (1999). “Scanning documents”. Retrieved 23 September, 2010 at]

Useful Links

[DIY Book Scanners:]

[Image Scanner:]

[Book Scanning:]


[How to Scan a Book:]

[3D Scanning:]

[Ultrasound Imaging:]

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