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OPTICAL DEVICES
Optics:
Branch of physical science dealing with the propagation and
behavior of light. In a general sense, light is that part of the
electromagnetic spectrum that extends from X rays to microwaves and
includes the radiant energy that produces the sensation of vision (see
Electromagnetic Radiation; Energy; Spectrum; X Ray). The study of optics
is divided into geometrical optics and physical optics, and these branches
are discussed below.
Optical Device:
A device for producing or controlling light.
Type of optical Devices:
There are some well known optical input devices.
Optical mouse
Optical Scanner
Optical Storage Devices
WI Remote
Optical Mouse:
An optical mouse uses a light-emitting diode (LED) and a small
CCD (charge coupled device) camera to detect motion. Modern optical
mice can work on virtually any surface. The early designs for optical mice
used two lights of different colors, and a special mouse pad that had a
grid of lines in the same two colors, one color for vertical lines and another
for horizontal lines
Optical Scanner:
A computer input device that uses light-sensing equipment to
scan paper or another medium, translating the pattern of light and dark
(or color) into a digital signal that can be manipulated by either optical
character recognition software or graphics software. A frequently
encountered type of scanner is “flatbed,” meaning that the scanning
device moves across or reads across a stationary document. On a flatbed
scanner such as the common office copier, such objects are placed face
down on a flat piece of glass and scanned by a mechanism that passes
under them. Another type of flatbed scanner uses a scanning element
placed in a stationary housing above the document.
Other scanners work by pulling in sheets of paper, which are
scanned as they pass over a stationary scanning mechanism, as in the
common office fax machine. Some specialized scanners work with a
standard video camera, translating the video signal into a digital signal for
processing by computer software.
A very popular type of scanner is the hand-held scanner, so
called because the user holds the scanner in his or her hand and moves it
over the document to be scanned. Hand-held scanners have the
advantage of relatively low cost; however, they are somewhat limited by
their inability to scan areas more than a few inches wide
Optical storage,
The typical Optical disc, stores information in deformities on the
surface of a circular disc and reads this information by illuminating the
surface with a laser diode and observing the reflection. Optical disc
storage is non-volatile. The deformities may be permanent (read only
media), formed once (write once media) or reversible (recordable or
read/write media). The following forms are currently in common use:
CD, CD-ROM, DVD, Blu-ray Disc, HD DVD: Read only storage, used
for mass distribution of digital information (music, video, computer
programs)
CD-R, DVD-R, DVD+R: Write once storage, used for tertiary and offline storage
CD-RW, DVD-RW, DVD+RW, DVD-RAM: Slow write, fast read storage,
used for tertiary and off-line storage
Magneto-optical disc storage
Magneto-optical disc storage is optical disc storage where the magnetic
state on a ferromagnetic surface stores information. The information is
read optically and written by combining magnetic and optical methods.
Magneto-optical disc storage is non-volatile, sequential access, slow
write, fast read storage used for tertiary and off-line storage.
3D optical data storage has also been proposed.
WI Remote
The, sometimes nicknamed "Wii mote", is the primary
controller for Nintendo's Wii
console. A main feature of the
Wii Remote is its motion sensing
capability, which allows the
user to interact with and
manipulate items on screen via
movement
and
pointing
through
the
use
of
accelerometer and optical
sensor technology. Another
feature is its expandability
through the use of attachments
The Wii Remote was announced at the Tokyo Game
Show on September 16, 2005. It has since received much
attention due to its unique features and the contrast between it
and typical gaming controllers. It has also gained significant attention
from hackers using it to control non Wii-related devices through Wii
homebrew
It was first designed in November 19, 2006 by Nintendo for Video game
controller .Its speed was16 KB EEPROM chip (16.3 kilobytes) and its source
of connection is Bluetooth.
Laser range-finder
A laser range-finder is a device which uses a laser beam in order to
determine the distance to a reflective object. The most common form of
laser range-finder operates on the time of flight principle by sending a
laser pulse in a narrow beam towards the object and measuring the time
taken by the pulse to be reflected off the target and returned to the
sender. Due to the high speed of light, this technique is not appropriate
for high precision sub-millimeter measurements, where triangulation and
other techniques are often used.
Light Pen
Light Pen, a pointing device in which the user holds a wand, which is
attached to the computer, up to the screen and selects items or chooses
commands on the screen (the equivalent of a mouse click) either by
pressing a clip on the side of the light pen or by pressing the light pen
against the surface of the screen. The wand contains light sensors and
sends a signal to the computer whenever it records a light, as during close
contact with the screen when the non-black pixels beneath the wand's
tip are refreshed by the display's electron beam. The computer's screen is
not all lit at once—the electron beam that lights pixels on the screen
traces across the screen row by row, all in the space of 1/60 of a second.
By noting exactly when the light pen detected the electron beam passing
its tip, the computer can determine the light pen's location on the screen.
The light pen doesn't require a special screen or screen coating, as does a
touch screen, but its disadvantage is that holding the pen up for an
extended length of time is tiring to the user. See also Automation;
Computer-Aided Design/Computer-Aided Manufacturing; Graphics
Tablet; Touch Screen.
Assignment #: 3
Audio & Video
Input Devices
By: Syed Adeel Ali
(SP08-BCE-080)
To: Mr. Engr. Bilal Qasim
Dated: 10th March, 2008