MGMT 1050 Lecture Notes - Lecture 12: Image Scanner, Surface Acoustic Wave
MGMT 1050 Tutorial 12 Notes – Multimedia Devices and Scanners
Introduction
Scanners
• Common technologies include resistive, capacitive, and surface acoustic wave.
• Some touch screens are capable of detecting multiple touch points.
• Scanners are the primary means used to input paper images.
• Although video frame grabbers and television cameras can also be used for this
purpose, scanners are generally less expensive and more convenient.
• There are three primary types of scanners, flatbed scanners, sheet-fed scanners, and
handheld scanners
• All three work similarly and differ only in the way the scan element is moved with
respect to the paper.
• In a flatbed scanner, the paper is placed on a glass window, while the scan element
moves down the page, much like a copy machine.
• In a sheet-fed scanner, a single page of paper is propelled through the mechanism with
rollers
• The scan element is stationary. Handheld scanners are propelled by the user over the
page.
• Regardless of which means is used, the basic operation is the same.
• The scanning mechanism consists of a light source and a row of light sensors.
• As the light is reflected from individual points on the page, it is received by the light
sensors.
• Translated to digital signals that correspond to the brightness of each point.
• Color filters can be used to produce color images, either by providing multiple sensors
or by scanning the image three times with a separate color filter for each pass.
• The resolution of scanners is similar to that of printers, approximately 600–2400 points
per inch.
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