FREE ESSAY ON ADVANCEMENTS IN PERIPHERALS

ADVANCEMENTS IN PERIPHERALS

Recent Developments in Computer Peripherals 
Including an in-depth look at Multimedia Input Devices
A Report by
Mr Matthew James Smith
HNC BIT Year One
Contents
Title Page Number 
Introduction Two
Section One -
Development in Peripherals Three
Section Two -
Multimedia Input Devices Five
Section Three -
An in-depth look Digital Cameras Six
The History of the Digital Camera Six
How Digital Cameras Work Seven
Conclusion Nine
Appendix / References Ten
Glossary Eleven
Introduction
Peripheral Devices
A Peripheral device is any external device attached to a computer. Without Peripherals a
computer is just a box full of wires, transistors and circuits, which is able to: -
1. Respond to a specific set of instructions in a well-defined manner.
2. Execute a prerecorded list of instructions (a program). 
The only problem being that without any input Peripherals you cannot tell the computer to
do any of the above processes, and if you could, without an output device of some kind,
the computer has no way of delivering the result to the user!
Examples of peripherals include printers, disk drives, display monitors, keyboards, and
mice etc.
These can be separated into two categories: -
Input devices
An input device is any machine that feeds data into a computer. For example, a keyboard
is an input device. Input devices other than the keyboard are sometimes called alternate
input devices. Mice, trackballs, and light pens are all alternate input devices.
Output devices
An output device is any machine capable of representing information from a computer. This
includes display screens, printers, plotters, and synthesizers.
C.P.U.
Central Processing Unit
Fig One
Section One -
Developments in Peripherals in the Last Few Years
There have been many advances in the field of Peripherals over the last few years. Even
the humble keyboard and mouse have been re-invented to produce the Ergonomic keyboard and
the cordless and laser mouse. There have also been advances in monitors such as flat
screen displays and LCD screens. But there have also been advances in technology, which
although not new, have been made commercially available for home use such as the digital
camera, scanners, digital video camera and the colour printer. To look at some of the
advances in detail we should put them into their categories.
Output Devices
Printers
Printers have developed from the daisy wheel printer to the thermal printers of today.
Other advancement in printers have been the laser printer (Same technology as
photocopiers), which is used commonly in offices as it produces very high quality text
and graphics. I general the Printer has developed in four areas. It has made improvements
in the quality of type, the speed in which it can print, the quality of graphics and the
number of fonts now available.
Monitor (Display Screen)
Monitors a few years ago were usually monochrome, displaying only two colours. E.g.
orange and black or green and black. Another type of "Old Style" monitor is a Grey Scale
monitor. This type of monitor displays different shades of grey. These monitors are now
used in the minority. Most of the Monitor used today are colour monitors, capable of
displaying 16 to over one million different colours! There are a number of different
types of colour monitor as shown in the table below.
Video Standard Resolution Simultaneous Colors 
VGA (Video Graphics Array) 640 by 480 16
320 by 200 256
SVGA (Super Video Graphics Array) 800 by 600 16
1,024 by 768 256
1,280 by 1,024 256
1,600 by 1,200 256
XGA (Extended Graphics Array) 640 by 480 65,536
1,024 by 768 256
Input Devices
Mouse
A mouse (Fig 2) is the device that controls the movement of the cursor or pointer on a
display screen. The mouse has been around about 40 years. It was invented by Douglas
Engelbart of Stanford Research Center in 1963, and pioneered by Xerox in the 1970s. The
mouse is one of the great breakthroughs in computer ergonomics because it frees the user
to a large extent from using the keyboard. In particular, the mouse is important for
graphical user interfaces because you can simply point to options and objects and click a
mouse button. Such applications are often called point-and-click programs. A significant
advance in the use of the mouse is the cordless mouse. The mouse isn't physically
connected to the computer at all. Instead it relys on infrared or radio waves to
communicate with the computer. Cordless mice are more expensive than normal mice, but it
does eliminate the cord, which can sometimes get in the way. Other advances in mice have
been 
Keyboard
The keyboard is the most commonly used peripheral for inputting information onto a
computer. The standard layout of letters, numbers, and punctuation is known as a QWERTY
keyboard because the first six keys on the top row of letters spell QWERTY. The QWERTY
keyboard was designed in the 1800s for mechanical typewriters and was actually designed
to slow typists down to avoid jamming the keys. This type of arrangement is still used
today but has not advanced much with the exception of the ergonomic Keyboard. This was
designed to allow more effective use of the QWERTY layout.
Section Two -
Multimedia Input Devices 
But the above peripherals have not had nearly as much advancement as multimedia
peripherals. This is the use of computers to present text, graphics, video, animation,
and sound in an integrated way. Long touted as the future revolution in computing,
multimedia applications were, until the mid-90s, uncommon due to the expensive hardware
required. With increases in performance and decreases in price, however, multimedia is
now commonplace. Nearly all PCs are capable of displaying video, though the resolution
available depends on the power of the computer's video adapter and CPU. 
Because of the storage demands of multimedia applications, the most effective media are
CD-ROMs. 
Listed below are some of the devices, which are now commonplace in our homes.
Optical Scanner
Scanners are used to scan in images and are used in conjunction the graphics
applications. Scanners can also scan text by making use of OCR (Optical Character Reader)
technology, which can then be manipulated in word processing applications. Most home
scanners are Flat Bed Scanners. Flatbed Scanners are like a photocopy machines. It
consists of a board on which you lay books, magazines, and other documents that you want
to scan.
Digital Camera
A digital camera stores images digitally rather than recording them on film. Once a
picture has been taken, it can be downloaded to a computer system, and then manipulated
with a graphics program and printed. Unlike film photographs, which have an almost
infinite resolution, digital photos are limited by the amount of memory in the camera,
the optical resolution of the digitising mechanism, and, finally, by the resolution of
the final output device. Even the best digital cameras connected to the best printers
cannot produce film-quality photos. However, if the final output device is a laser
printer, it doesn't really matter whether you take a real photo and then scan it, or take
a digital photo. In both cases, the image must eventually be reduced to the resolution of
the printer. 
The big advantage of digital cameras is that making photos is both inexpensive and fast
because there is no film processing. Interestingly, one of the biggest boosters of
digital photography is Kodak, the largest producer of film. Kodak developed the Kodak
PhotoCD format, which has become the de facto standard for storing digital photographs. 
Web Cam
A web cam is similar to a digital camera, but instead of taking still shots, it can
stream images much like a video camera. Thus enabling the user to send live video form
their computer across the Internet. 
Section Three - 
An in-depth look Digital Cameras
History
The history of the digital camera starts with the evolution of the television, back in
the 1940's and 50's. When television was first broadcast it was all live. A way had to be
found to record the images being broadcast. In 1951 Bing Crosby laboratories introduced
the VTR, which recorded the electrical impulses onto magnetic tape. By 1956 the VTR
technology worked well, and it began to have a large impact on the television industry.
This, tied in with the development of computers in the 1950's started the digital age. 
The next large step occurred with NASA in the 1960's. Before NASA sent astronauts to the
moon, probes were sent to map the surface of the moon. These probes sent back analogue
signals to earth, NASA engineers found that the transmissions were too weak to compete
with natural radio sources in the cosmos. Current television receivers could not decipher
the images sent back from the moon, so NASA engineers had to find a way to enhance and
sharpen the images. Images were processed through a computer and turned into a digital
signal, and all noise and corruption of the data was removed. By the time Apollo went to
the moon, transmissions were coming back crystal clear. 
After that the cold war accelerated development of digital imaging, mostly used for spy
satellites and imaging systems.
In 1995 Kodak released the dc40 and at under a $1000 it was the first digital camera
marketed for consumers. The Apple QuickTake 100 was also made available at the same time.
Both connected to the computer via serial cable. 
How Digital Cameras Work
No two digital cameras are the same, and therefore this explanation of how a digital
camera works is merely a generalization of the internal process of how a digital camera
takes a picture. There are two versions of this description, an entry level description
meant for the casual user who just wants to know how a digital camera works in general,
and in relation to a 35mm camera. The other description is a little more technical, and
for this review click here. As the internal workings on each camera works a little
differently the following information may not be 100% correct as per your digital
camera.
A digital camera is similar to a 35mm camera in the way that it takes pictures and stores
them on some sort of memory card. The way a digital camera differs from a 35mm camera is
what's inside. When you prepare to take a picture on your digital camera, (by pressing
the shutter release button half way down), the auto focus (if you are using it.), is
applied, the CCD (charged-couple device) charges up and becomes prepared for the picture
to be taken, and possibly the flash prepares to be used. Once the shutter button is fully
depressed, the shutter will open, allowing light to enter the camera and strike the CCD.
The light is then measured electronically on the CCD and is then sent off to the internal
memory of the camera, called the buffer. Once the image information reaches the buffer,
it is then compressed (if selected) into JPEG format. The completed image is then
transferred to the memory card on the camera. Some cameras will need this process to
finish before taking another picture, some cameras have an internal buffer that is large
enough to hold a number of pictures, and can therefore take multiple pictures in a row,
called burst shooting. 
Before a picture is taken the camera must prepare for it. That is why there is sometimes
a delay from when the shutter release button is pressed and when the picture is actually
taken. Newer cameras have much faster response times, but some of the old cameras have
quite a noticeable lag. To prepare for a picture to be taken, the shutter release button
is pressed halfway and the camera performs a number of operations. If the camera has some
of it's automatic functions turned on, one or more of the following may need to be
performed, the auto focus will need to focus in on the target, the white balance,
exposure time and shutter speed need to be calculated, and the CCD (Charged-Couple
Device) must be charged, as it can't hold a charge very long. Once the shutter release
button is pressed, the shutter is opened, and it allows light to pass though the lens and
strike the CCD. 
The CCD is made up of (usually) millions of tiny sensors that record the amount of light
that hits them. The sensors only record the amount of light that hits them, not the
colour of the light. For the digital camera to detect what colour is in each pixel, a
special method is used. To capture colour, the digital camera applies a colour filter
over the individual sensors, the filter is usually applied directly to the CCD using dye.
The most common filter used is the Bayer filter, see the table at the bottom of this page
for an example. This image would be 4 pixels square on the CCD, a 2x2 pixel pattern
repeating thousands of times consisting of Red, Blue, and Green filters, and as you may
have noticed there are twice as many green squares as red and blue. This is because human
eyes have sensitivity to the luminescence properties of green, because it is in the
middle of the spectrum. So a 1 mega pixel camera will have 540,000 green pixels, 270,000
red pixels, and 270,000 blue pixels. A few manufacturers use a different method involving
4 colours, (Cyan, Green, Magenta, and Yellow), see in the table below. Using this method
there are an equal number of pixels for each colour.
Bayer filter CMYK filter
There are two different settings that determine how much light strikes the CCD, the
shutter speed, which determines how long the light stays on the CCD, and the aperture
setting, which determines how much light hits the CCD. After the light strikes the CCD,
the individual sensors convert the amount of light hitting them into an electrical
signal, which is originally stored as an analogue signal, and is converted to a digital
signal by a analogue to digital converter (ADC). 
Each of these sensors represents 1 pixel, and the actual 24-bit colour is determined by
the average of the pixel and all of its neighbours. The information on the CCD is then
read one horizontal line at a time to the internal memory of the camera, and on their way
to internal memory they pass through the internal filters, such as white balance and
colour. The internal memory then stitches all of the individual pixels into an image. The
image in its uncompressed form is then (if selected), compressed. The compression is
almost always JPEG compression, and JPEG is named after the committee that designed it,
the Joint Photographic Experts Group. The JPEG method is based on the fact that humans
are much more aware of small changes in brightness (luminance) than small changes in
colour or large changes in colour or brightness. The JPEG compression algorithm works
well and can easily achieve a 10:1 or 20:1 (or more) compression ration, depending on the
compression settings, with minimal visible image quality loss. After all this happens the
image is then saved to the memory device of the camera, whether it be Smart Media,
Compact Flash, or some other type of memory, (see our Memory section of this site to see
the differences between the different types of storage media).
Conclusion
In the last few years, computers have become more affordable to the general public. But
they have also had an exponential advancement in memory, processing power and software
applications. With the use of the Internet and E-mail, this combination has prompted an
explosion in the manufacture of peripherals which are able to benefit from these
advancements. In the last five years, peripherals, especially Multimedia Peripherals,
have made the Personal Computer an almost essential household appliance. In the next few
years we can expect to see advancements in peripherals which may one day prompt the next
computer revolution.
Appendix/References
To produce this report, I consulted some computer magazines (PC Pro, What PC, PC Buyer)
and some mail order catalogues (Global Direct, Dabs Direct, Simply), but the information
on these magazines are only correct at the time of going to press. Also, they provided
little in the way of information about the product such as how it worked and its
history.
While searching on the World Wide Web I found websites such a Webopedia.com. This site
offered an online directory of computer terms and thorough explanations with diagrams. I
also found ComputerUser.com, this is a website with offers a "Hi Tech" dictionary which
helped in explaining some of the terms I was encountering. Another site which had many
recourses to offer was Cnet.com. But the site which I found most useful was
DigitalCamera.Com. This site offered a vaiety of information on the subject I had chosen
to white about in this report.
In conclusion, this report would have been much less informative if it were not for the
up-to-date information offered by the Internet.
Glossary
Aperture The aperture in a camera determines how much light strikes the CCD, a small f
number on the camera indicates a larger aperture, and a large f number indicates a
smaller aperture. Many cameras allow you to change the f number, which corresponds to the
aperture size. The f number corresponds to how big the aperture is in relation to the
lens. A f/4 aperture setting means that the aperture is one quarter the size of the lens.
A f/10 setting means that the aperture is one tenth the size of the lens. 
Buffer The buffer is the internal memory in the digital camera, it stores the pictures
after the information comes off of the CCD. The internal memory also helps in burst
shooting, as it will hold a number of pictures as the camera takes pictures. 
CCD CCD stands for Charged-Couple Device. The CCD is the part of the digital camera that
converts light to an electric signal useable by the digital camera's electronics. The CCD
is made up of (usually) millions of tiny sensors that record the amount of light that
hits them, each sensor contains the information for one pixel. The sensors only record
the amount of light that hits them, not the color of the light. For the digital camera to
detect what color is in each pixel, a special method is used. To capture color, the
digital camera applies a color filter over the individual sensors, the filter is usually
applied directly to the CCD using dye. 
Digital The storage of data in the form of binary numbers, 0 and 1. Digital information
can be copied and stored with no loss of information. 
JPEG JPEG is named after the committee that designed it, the Joint Photographic Experts
Group. The JPEG method is based on the fact that humans are much more aware of small
changes in brightness (luminance) than small changes in color or large changes in color
or brightness. The JPEG compression algorithm works well and can easily achieve a 10:1 or
20:1 (or more) compression ration, depending on the compression settings, with minimal
visible image quality loss. 
LCD Stands for Liquid Crystal Display. This is usually the small screen on the back of
the digital camera, though not all cameras have them. Used to display camera information,
menu systems, and can be used as a viewfinder. Most LCD's are difficult to see in bright
sunlight, due to the fact that the sun's rays overpower the light being emitted by the
screen. 
Pixel A pixel is one dot that carries the information from the optical sensor on the CCD
to the image itself. Each pixel displays one color and all of the pixels together produce
the image. 
Shutter The shutter is a device which limits how long light strikes the CCD, the amount
of light is determined by the shutter speed and the aperture setting. The shutter differs
between digital cameras, some will use a physical shutter, and some use an electronic
shutter. The physical shutters will allow light to strike the CCD by letting light past
some kind of physical barrier. The electronic shutters will turn the CCD on for the time
allotted by the shutter speed. 
Shutter Release Button This is the button that you use to take your picture, this button
is sometimes used to prepare the camera for picture taking. Pressing the shutter release
button halfway may (depending on your camera, and its settings), focus the auto focus,
prepare the flash, adjust the white balance, exposure time, and shutter speed. Pressing
the shutter release button all the way down will open the shutter and the picture will be
taken. 
Shutter Speed The shutter speed is the length of time that the CCD is exposed to light.
Shutter speed times range from very short, up to 1/10000 of a second to infinitely long.
Small shutter speeds are better for action shots. 
White Balance The white balance relates to what the camera determines as the color white
in the image. Different light conditions will result in the color white appearing
differently. Some cameras will offer automatic white balance, this will allow the camera
to choose the white setting based on what it thinks should be white in the picture.
Sometimes this will be a problem is there is a dominant color in the picture that is not
white. Other cameras have a number of white balance presets, including fluorescent,
sunlight, cloudy, and others.