pctechguide.com

  • Home
  • Guides
  • Tutorials
  • Articles
  • Reviews
  • Glossary
  • Contact

Scanner Operation

On the simplest level, a scanner is a device which converts light (which we see when we look at something) into 0s and 1s (a computer-readable format). In other word, scanners convert analogue data into digital data and can have a Document Data Capture.

All scanners work on the same principle of reflectance or transmission. The image is placed before the carriage, consisting of a light source and sensor; in the case of a digital camera, the light source could be the sun or artificial lights. When desktop scanners were first introduced, many manufacturers used fluorescent bulbs as light sources. While good enough for many purposes, fluorescent bulbs have two distinct weaknesses: they rarely emit consistent white light for long, and while they’re on they emit heat which can distort the other optical components. For these reasons, most manufacturers have moved to cold-cathode bulbs. These differ from standard fluorescent bulbs in that they have no filament. They therefore operate at much lower temperatures and, as a consequence, are more reliable. Standard fluorescent bulbs are now found primarily on low-cost units and older models.

By late 2000, Xenon bulbs had emerged as an alternative light source. Xenon produces a very stable, full-spectrum light source that’s both long lasting and quick to initiate. However, xenon light sources do consume power at a higher rate than cold cathode tubes.

To direct light from the bulb to the sensors that read light values, CCD scanners use prisms, lenses, and other optical components. Like eyeglasses and magnifying glasses, these items can vary quite a bit in quality. A high-quality scanner will use high-quality glass optics that are colour-corrected and coated for minimum diffusion. Lower-end models will typically skimp in this area, using plastic components to reduce costs.

Flatbed

The amount of light reflected by or transmitted through the image and picked up by the sensor, is then converted to a voltage proportional to the light intensity – the brighter the part of the image, the more light is reflected or transmitted, resulting in a higher voltage. This analogue-to-digital conversion (ADC) is a sensitive process, and one that is susceptible to electrical interference and noise in the system. In order to protect against image degradation, the best scanners on the market today use an electrically isolated analogue-to-digital converter that processes data away from the main circuitry of the scanner. However, this introduces additional costs to the manufacturing process, so many low-end models include integrated analogue-to-digital converters that are built into the scanner’s primary circuit board.

The sensor component itself is implemented using one of three different types of technology:

  • PMT (photomultiplier tube), a technology inherited from the drum scanners of yesteryear
  • CCD (charge-coupled device), the type of sensor used in desktop scanners
  • CIS (contact image sensor), a newer technology which integrates scanning functions into fewer components, allowing scanners to be more compact in size.
  • Scanner Operation
  • PMT Scanners
  • CCD Scanners
  • CIS Scanners
  • Scan Resolution
  • Scanner Interpolation
  • Color Scanners
  • Bit-Depth Printers
  • Dynamic Range Scanners
  • Scan Modes
  • Scanner File Formats
  • TWAIN Drivers
  • Color Calibration
  • OCR Technology
  • Photo Retouching

Filed Under: Scanners

Latest Articles

ADSL2 Speed and wiki – History of ADSL2

Even before designs based on the first generation standards (ITU G.992.1 and G.992.2) had been perfected, the ITU had been working on a latter revisions of the ADSL standard. In July 2002, the ITU completed two new ADSL standards - designated as … [Read More...]

Cinepak technology

Cinepak is another asymmetric video compressor, developed jointly by Apple and SuperMac (a company later acquired by Radius). The format outputs 320x240 (quarter screen) at 15 fps with good quality, at a data rate that even slow … [Read More...]

IVI Technology

Shortly after the introduction of Apple QuickTime, Intel responded with its Indeo Video Interactive (IVI or Indeo 4.0) codec. This format allows for scaleable software-only video playback. IVI can compress video symmetrically (in real time, … [Read More...]

Comments

  1. Pergolesi says

    May 8, 2012 at 3:47 pm

    What is the date of this article?

  2. iknf says

    September 8, 2013 at 5:39 pm

    not bad

Gaming Laptop Security Guide: Protecting Your High-End Hardware Investment in 2025

Since Jacob took over PC Tech Guide, we’ve looked at how tech intersects with personal well-being and digital safety. Gaming laptops are now … [Read More...]

20 Cool Creative Commons Photographs About the Future of AI

AI technology is starting to have a huge impact on our lives. The market value for AI is estimated to have been worth $279.22 billion in 2024 and it … [Read More...]

13 Impressive Stats on the Future of AI

AI technology is starting to become much more important in our everyday lives. Many businesses are using it as well. While he has created a lot of … [Read More...]

Graphic Designers on Reddit Share their Views of AI

There are clearly a lot of positive things about AI. However, it is not a good thing for everyone. One of the things that many people are worried … [Read More...]

Redditors Talk About the Impact of AI on Freelance Writers

AI technology has had a huge impact on our lives. A 2023 survey by Pew Research found that 56% of people use AI at least once a day or once a week. … [Read More...]

11 Most Popular Books on Perl Programming

Perl is not the most popular programming language. It has only one million users, compared to 12 million that use Python. However, it has a lot of … [Read More...]

Guides

  • Computer Communications
  • Mobile Computing
  • PC Components
  • PC Data Storage
  • PC Input-Output
  • PC Multimedia
  • Processors (CPUs)

Recent Posts

CD-RW Installation Connection

As well as configuration jumper blocks, the back of the CD-ReWriter has a number of connectors. Each of these will need to be connected to the … [Read More...]

USB Flash Drives

These are not "drives" at all - the misnomer was gained as they were intended to replace old portable drive technology. Offering massive storage and … [Read More...]

Top Computer Privacy Issues You Need to Know

The internet impacts every aspect of your life, irrespective of which part of the world you are in. Whether you're scouting for information for your … [Read More...]

[footer_backtotop]

Copyright © 2025 About | Privacy | Contact Information | Wrtie For Us | Disclaimer | Copyright License | Authors