A: A scanner is a wonderful device that can be used for the following:
· to copy documents
· to capture images from photographic prints, posters, magazine pages, and similar sources for computer editing and display
· works much like a photocopy machine, but instead of just creating an image on a piece of paper it can also create digital image that can be displayed on a computer screen, manipulated, e-mailed and or printed
· to convert photographs, slides, and three-dimensional objects into files that can be pasted into a brochure, inserted into a presentation or posted on the Internet
Sources: whatis.com; How to use a Scanner, Sandy Berger, www.aarp.org; buyerzone.com
Q: What are the different types of scanner?
A: Below is a list of different scanner types.
· Flatbed - Most flatbed scanners can scan paper documents, books, photographs, and other flat objects such as leaves or pieces of fabric. It is constructed with a flat glass plate over the photosensitive array and a cover to go over the glass. Light emitted from under the glass reflects off the object being scanned and is picked up by the moving CCD array in the scan head. Flatbeds are mostly made to fit a piece of 8.5" x 11" (A4) paper or photo to be placed on its scanning area. This type of scanner consumes space.
Note: CCD (charge-coupled device) array is the core component of a scanner-the most common technology for image capture in scanners.
· Film Scanner - Also known as slide and negative scanner. It has a high optical resolution and is more compact than a flatbed scanner. The operation theory is just like the flatbed scanner but it is designed only for film scanning.
· Drum-type - Mostly used by the publishing industry to capture incredibly detailed images. They apply a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder.
Sources: Buying Guide- Scanner, View Z; How To Use a Scanner, Sandy Berger, www.aarp.org; Understanding and Choosing a Scanner (Part 1), Larry Chan; howstuffworks
Q: Which type of scanner is the most widely used?
A: A flatbed scanner is very versatile and easy to use that's why it is the most popular among end-users. It is possible to scan almost everything that fits onto its scanning surface: from documents, to photos and even 3D objects. There are also flatbed scanners that can scan slides, negatives, and transparencies with the help of software and adaptor.
Source: Understanding and Choosing a Scanner (Part 1), Larry Chan
Q: What determines the image quality of the scanner?
A: The scanner's bit depth (color depth) and resolution contribute to the quality of image it turns out. Bit depth refers to the amount of information the scanner can remember about each pixel (picture elements) it reads. When you encounter the term bit depth, always bear in mind that the higher the bit depth, the better the scanner is at distinguishing between really close shades of the same color This produces higher image quality. The minimum bit depth for decent image quality is 24 bits.
Resolution is a measure of how many pixels a scanner assigns to a given image/document. The unit of measuring resolution is dpi (dots per inch) or ppi (pixels per inch). The higher the resolution, the more detailed the image appears. However, the higher the resolution, the larger the file, and it will eat up a lot of space on your hard drive. Images scanned at a very high resolution can be massive, so, always use the resolution that fits your need.
In scanners there are two types of resolution namely: optical and interpolated (enhanced). Optical resolution is the more important and reliable kind because it measures the true number of pixels as compared to interpolated resolution, which uses mathematical computations to increase the number of pixels scanned.
For the average user an optical resolution of 300dpi will suffice. With this kind of resolution the scanned image will look good on the web or printed out on an inkjet or laser printer.
Sources: Buying Guide- Scanner, View Z; How To Use a Scanner, Sandy Berger, www.aarp.org; buyer zone.com
Q: When you buy a scanner does it automatically have a software/driver?
A: You must not forget to ask for the software/driver when you buy a scanner. The bundled software is part of the package that you buy. The bundle will probably contain a driver program, colour calibration software, image-editing software and optical recognition software (OCR). For Windows the driver program is usually TWAIN compatible.
TWAIN is the industry standard used to obtain scan information and transfer that information between scanner and computer A TWAIN driver allows imaging devices like scanners to be compatible with TWAIN-supported software. Since TWAIN is an industry standard most bundled software will operate off TWAIN.
Sources: Buying Guide- Scanner, View Z; How To Use a Scanner, Sandy Berger, www.aarp.org;
Q: How does a scanner connect to a computer?
A: Connecting the scanner to the computer can be through the parallel port, USB, and SCSI.. The parallel port connection is the slowest among the three mentioned. USB offers straight-forward installation, flexible configuration and faster data transfer. Small Computer System Interface or SCSI is a fast type of connection but can require more work to configure and install.
Source: Buying Guide- Scanner, View Z
The Quest Corner is a regular column by Quest Computer Store dedicated to computer end-users especially the newbies. For comments and suggestions you can send it to: timmy@questcomputer-store.com or call our HOTLINE 851-1688
