Scanning
From CIRCA
VTracker |
---|
Content inserted. (177 Occurances) |
Content structure inserted. (176 Occurances) |
Content changed. (2 Occurances) |
Content moved. (5 Occurances) |
Content NEED DESCRIPTION. (2 Occurances) |
Content NEED DESCRIPTION. (2 Occurances) |
Content structure moved. (1 Occurances) |
Content style of a font changed. (13 Occurances) |
UGOCHUKWU UDEMEZUE ONYIDO
Presented on September 23, 2010
Contents |
Scanning Technology
This brief paper discusses the basics of scanning technology,its history and development, related technologies, significance,and its place in the future.
Introduction/Background
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).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 TechnologyScanning 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).
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.
There are several types of scanner but the following scanners identified by Wikipedia can suffice:
Significance
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:
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.
History
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
Future
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.
Conclusion
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.
References
[Electronic Imaging Systems (2007). Retrieved 23 September, 2010 at http://www.eisca.com]
[Online Technology Learning Centre (2002). Tuscaloosa City Schools. ???Scanners and scanning???. Retrieved 22 September, 2010 at http://www.online.tusc.k12.al.us/tutorials/scanning/scanning.htm]
[Spinella E, (2002). ???Biometric scanning technologies: finger, facial and retinal scanning???. SANS Institute - InfoSec Reading Room. Retrieved 23 September 2010 at http://www.sans.org]
[ThinkQuest. ???Paul Nipkow: co-invented the television???. Projects by Students for Students Retrieved 23 September 2010 at http://library.thinkquest.org/26451/contents/inventors/nipkow.htm]
[Virtual Training Help Centre (2002). Bloomberg University. ???Digital images???. Retrieved 22 September, 2010 at http://iit.bloomu.edu/vthc/DigitalImages/Basics/intro.htm]
[Wikipedia. ???Colour depth???. Retrieved 22 September, 2010 at http://en.wikipedia.org/wiki/Color_depth]
[Wikipedia. ???Image scanner???. Retrieved 24 September, 2010 at http://en.wikipedia.org/wiki/Image_scanner#Drum]
[Wikipedia. ???RGB colour models???. Retrieved 30 September, 2010 at http://en.wikipedia.org/wiki/RGB_color_model]
[WordNet. ???Scanning???. Princeton University. Retrieved 22 September, 2010 at http://wordnetweb.princeton.edu/perl/webwn?s=scanning]
[Xerox, (1999). ???Scanning documents???. Retrieved 23 September, 2010 at http://www.office.xerox.com/small-business/tips/scanning/enus.html]
Useful Links
[DIY Book Scanners: http://www.wired.com/gadgetlab/2009/12/diy-book-scanner]
[Image Scanner: http://en.wikipedia.org/wiki/Image_scanner#Drum]
[Book Scanning: http://en.wikipedia.org/wiki/Book_scanning]
[OCR: http://en.wikipedia.org/wiki/Optical_character_recognition]
[How to Scan a Book: http://www.proportionalreading.com/scan.html]
[3D Scanning: http://en.wikipedia.org/wiki/3D_scanner]
[Ultrasound Imaging: http://www.radiologyinfo.org/en/info.cfm?pg=genus]