Download - Multimedia Input
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MULTIMEDIA INPUT/OUTPUT
TECHNOLOGIES
UNDER GUIDANCE OF :-
Prof: YOGESH CHAUDHARY
By:-
PRANJAL SAIGAL(383).
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TOPICS TO COVER
Key Technology Issues Pen Input
Video And Image Display
Print output Technologies Image Scanners
Digital Voice and audio
Digital Camera Video Images and Animation
Full Motion video
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Key Technology Issues
Pen Input
Video And Image Display
Print output Technologies
Image Scanners
Digital Voice and audio
Digital Camera
Video Images and Animation
Full Motion video
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Key Technology Issue
The need of it was to get a balance between
them.
Earlier only text was the option but now we
have unlimited dimensions to work with.
Audio itself includes. capturing, enhancing,
compressing, retrieving.
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DOES IT MAKES A SENSE??
BALANCE BETWEEN THE PARTS OF THE SYSTEM INCLUDING HARDWARE AND
SOFTWARE CAN ONLY LEAD TO PROPER FUNCTIONING OF IT..
BULLOCK CART
TRUCK ENGINE
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INPUT DEVICES..
Keyboard is a basic device we have to deal
with non-GUI interface. Traditional alpha-
numeric data entry, later got modified too.
Multimedia objects such as image, sound,
video depend on input device and storage for
quality.
The display quality can not exceed the
capturing quality.
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Analog V/S Digital Input
In case of monochrome scanner only 1 or 0was there, then for grey scale 0 to 256 shadeswere available, for colored it was hue
intensity. For audio the microphone only produces
analog input, so has to be converted.
Light intensity level in video camera. So we need special program for this purpose
called codecs they do the conversions.
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Resolution and Bandwidth issues
The measure to quality of a object is resolution.
For images its pixels/inch,
Average of 100 pixels/inch.
200 pixel/inch is very good.
Official printers provide 300 to 600 pixels/inch.
Professional offset printers provide 1200 to 1800 pixel/inch.
For sound sampling rate and bits used for
representing amplitude,
4khz at 8 bit is minimal acceptable for(mono) voice-grade sound.
8khz at 16 bit for music quality.
Its up to 44.1khz at 16 bits for multichannel stereophonic sound.
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For video VCR quality is the minimum with 300
lines in screen upto 320 X 240 pixels.
For a HDTV we have 1280 X 1024 pixels. Another measure is number of bits palette used
for a HDTV 16 bits are used.
The next criteria is frames per second Low quality video have 15 frames/sec
A medium quality is about 30 frames/sec
TV operates at 60 frames /sec
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Key Technology Issues
Pen Input
Video And Image Display
Print output Technologies
Image Scanners
Digital Voice and audio
Digital Camera
Video Images and Animation
Full Motion video
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PEN INPUT Why pen????
Allows operations like point, pick, drag and click on an object. Gestures can be understood by the system and much enhanced
features are available now.
Best for unskilled people, individuality with help ofhandwriting is maintained.
Provides a better control than joystick or a mouse ball.
Used in palmtop(PDA) integrated cellular phones for pointingand dialing numbers.
Its more easy to draw with a pen than a mouse since a non-
electronic ink version is something we use in real life too. Very useful in data entry(converts the data to ASCII code
automatically)
It helps in power saving in palmtop.
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APPLICATION
WINDOWS
Recognizer
(Microsoft or
third party)
R C manager
Penwin.dl part of
pen windows
Dictionary
(from Microsoft
or third party)
Pen driver
(OEM supplied)
Display Driver
WINDOWS FOR PEN COMPONENTS IN MICROSOFT WINDOWS
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HOW DOES IT WORKS??
All this is done with the DLL files that are
provided by Microsoft. The digitizer responds to the movement of pen
by interrupts with its x and y coordinates.
This data is send to RC manager where theprocess of inking is done if the messages are
coming from the pen and its displayed on the
screen by display manager. Else if windows is sending messages then only
movement is recorded and no inking is done.
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ELECTRONIC PEN
The digitizer responds to the pen status including if
its touching the screen or not , pressure, angle, pen
rotation and so on.
It takes around 200 samples per second to track thepen movement and then generates the signals
The tip of pen contains a sensor that behaves as left
mouse button.
All this data is hence used for pointing selecting or
inking the object.
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DIGITIZER
The two most common digitizers are
1) A transparent digitizer bound to the surface of the screen
2) A separate tablet containing electronic digitizing circuit Bonded technology is now a days used in PDA or palmtop where
there is no space for a separate keyboard.
Where as a separate tablet is used in complex CAD systems wheremore accuracy is required.
Technically the working of digitizer is based on two concepts:-1) Electromagnetic digitizer:- The pen here contains a magnetic coil at
its tip which is sensed in terms of voltage generated by the coilbeneath it .
2) Electrostatic digitizer :- Here a grid of wires are available andvoltage is generated by the touch of the pen and this is converted
into useful signals both these technologies are analog.3) C:\Program Files\Synaptics\SynTP
The accuracy of the digitizer is measured in terms of number of lines itcan draw in an inch ,It can be up to 1000 lines per inch also.
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Pen driver The pen driver has two drivers : an installable windows pen
driver and a virtual driver.
All interrupts go to pen driver where packets are made ifwindows is at normal mode else in enhance mode theinformation goes to virtual driver then packets for pen driverare made there
Pen driver then sends packets to RC manager, therequirements for handwriting recognizer are:-
1) 100 packets/sec must be send to RC manager this is to ensure theobject is completely identified eg for letter I and j
2) It must have a 200 dots /inch resolution so that the sufficientgranularity is attained and object is recognized
3) Must report 0.001 inch in x and y coordinates for details of the object tobe correct
4) This is more application dependent eg to draw is still easy to write is acomplex job..
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Recognition Context manager(R C manager) This is the heart of the pen system it keeps a harmony between display,
recognizer, dictionary the pen message and mouse message
differentiation and inking(actual).
It basically recognizes hand written characters, symbols or drawings and
then ASCII equivalent characters are produced.
Its not limited to ASCII only it can also recognize non roman like Arabic
Devnagri and other languages.
Its concept is to break the design in to vectors which is then studies as a
32 bit information and is matched to all data for production of actual
word or character.
It can be made more specific by taking the sample of the handwriting of
the user before using this.
Then the best matching result is produced, options are then generated in
case of confusion to select form (eg car and can).
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DICTIONARY
This is to validate the recognition result. The word is
compared to best possible validation. Dictionary is a DLL ; it can be a language dictionary,
engineering dictionary for a special set of words that need to
be recognized, its possible to use multiple dictionary at a
time.
DISPLAY DRIVER
Its a DLL that interacts with the GDI(graphical device
interface) and display hardware.
It provides a distinctive new cursor a pen pointing innorthwest direction to distinguish it from mouse pointer.
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Key Technology Issues
Pen Input Video And Image Display
Print output Technologies
Image Scanners Digital Voice and audio
Digital Camera
Video Images and Animation
Full Motion video
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Graphic Revolution Most applications are with menu, icons , graphics
capabilities like pie chart ,bar graph etc.
Video brings life to applications animation which entertain,
educate and help us develop our senses.
Games are no longer just an entertainment thing, virtual
reality has made world safe and more experiencing thanever.
Modes of advanced communication have made the world
shrink manifold and brought us close to our dear ones.
The usage of technology is much easier after theintroduction of GUI.
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Display System Requirement Hypermedia documents and display o/p are expected to be
viewed on typical office computers that has wide range ofdisplay systems including VGA(),8514A,XGA & other high
resolution display.
A careful design and implementation is required for ensuring
that all applications can perform on all types of hardware.
Its not just about painting of the screen but attaining a high
level of compatibility is to be achieved.
So a negotiation is required between application and GUI
environment to scale the display info to the resolution
required by the workstation.
Increasing use of powerful low cost chips used for GUI that
combines image and graphics on one board for same screen.
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When we add image processing , synchronized audio, video
animation, full motion video make the equation more
complex.
Its not just about high resolution graphics, video imaging but
areas like scientific image analysis, machine vision, medical
vision, geophysical application and video conferencing have
also rapidly evolved.
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Display System Technologies
Important aspect is to resize the window to suit users preferences,because this causes number of pixels to change
Scaling down to a smaller size is done by dropping the pixel but scalingto a larger window requires adding pixels that do not exist in originallycaptured image.
The concept seems complicated?? But what about whenthis has to be done at 30 frames/sec???
This problem is addressed by mixing and scaling technologies in a singlemonitor.
VGA mixing : Images from various sources are mixed in the imageacquisition memory. An image once captured, is fixed in memory and itsx and y position and size are also fixed.
Mixing with scaling :Using scalar ICs can resize in predefined windowthis causes data lose in some cases and when both the tasks areperformed it might be a failure since same buffer is used so adiscontinuous o/p may be available.
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Dual buffer VGA mixing/scaling : The loss of original image isovercome by providing dual buffering. The original image ismaintained in a separate buffer so that another round of
scaling and resizing can be achieved dynamically. This is done by separate boards, or an add-on to mother
board this is a memory hungry scheme.
Hardware always adds to the cost so a software approach isessential.
Installing a daughter board provides a favor of their ownbackdoor bus for high-speed inter board transfer.
With availability of 80686 and Pentium software solutionsare more flexible except for most demanding applications.
Another approach is using digital signal processors (DSPs)examples of such are RS-170/NTSC or CCIR/PAL.
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DISPLAY PERFORMANCE ISSUES
The 3 main factors that affect the performance areNETWORK BANDWIDTH, DECOMPOSITION OR DECODING,
DISPLAY TECHNOLOGY NETWORK BANDWIDTH . This is important in case of client
server operation where data is resident on a LAN-connectedserver. It might become choppy and incoherent if the videois bandwidth is insufficient.
To optimize network and storage most design store andtransfer compressed data, which is decompressed at thetime of display.
Compression and decompression have to be highly effective
and optimized. Final component here is display technology, a motion video
may require repainting of screen up to 30 to 60 frames persecond thus buffer is required.
Vid Di l T h l S d d
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Video Display Technology Standards
IBM introduced MDA(Monochrome Display
Adapter)720X350 and CGA(Color Graphic Adapter) 640X200
in 1981. It could only display 25 row of alphanumeric text character.
Where as CGA was capable of both text and bitmap image,
with separate input signal for RGB. They were not
compatible.
Then came Hercules Monochrome Graphics Adapter just a
year later it could display both text and graphics at 720X350
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Resolution and Dot Pitch A screen resolution of a screen is the number of pixels per
scan line times the number of scan lines, e.g.: 1024x768
means 1024 pixels and 768 scan lines
Each pixel is a made of RGB phosphorus arranged in a triad.
The distance between one set of RGB to next RGB is the dotpitch.
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For a 14 inch monitor
Dp horizontal =(width in inches/no of pixel) x 25.4 mm
=(9.875/1024)x25.4
=0.24 mm
Dp vertical =(height in inches/no of lines) x 25.4 mm
=(7.125/768)x25.4
=0.24 mmFor a 17 inch monitor
Dp horizontal =(width in inches/no of pixel) x 25.4 mm
=(12.901/1024)x25.4
=0.32 mm Dp vertical =(height in inches/no of lines) x 25.4 mm
=(9.675/768)x25.4
=0.32 mm
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Hori ontal Refresh Rate Vertical Refresh Rate
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Horizontal Refresh Rate, Vertical Refresh Rate,
and Flicker
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Horizontal refresh rate or horizontal scan frequency is a
measure of the rate at which the scanlines are painted. Its
measured in kilohertz and VGA monitor has a horizontal
refresh rate of 31.5 KHz. Vertical refresh rate is close to horizontal it varies from 50 to
72 Hz
For a standard NTSC television signal, the vertical refresh
rate is 30Hz. Flicker is because of lower vertical refresh rate, and is
dependent on individuals persistence of vision.
If the vertical refresh rate is low successive images do not
appear fast enough for the brain to retain a continuoussense of the image(feels like turning on and off of light)
This is specially observed when a bright light is used in the
vicinity.
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Interlaced and Noninterlaced Scan Mode: In interlaced
mode, odd-numbered scan lines (1,3,5,7 and so on) are
scanned first and then even-numbered lined(2,4,6 so on) in
next pass. Thus it takes 2 passes to paint or refresh oneframe on screen in the next pass.
In non-interlaced mode it goes sequentially in one pass,
therefore the screen is repainted twice in same time.
For multimedia applications using non-interlaced mode isbetter since it reduces flicker.
Long-persistence phosphorus is used in interlaced mode
since it retains the brightness in the next pass, but the
drawback is retaining causes older scene to appear over new
one.
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Display Terminology
Triad : A triad consists of a set of red, green and blue
phosphors arranged in a triangle. Pixel: A pixel is made of a triad.
Convergence : if the beam of electron has divergence then
pure white color is not obtained and the monitor is not
perfectly aligned PINCUSHIONING:
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BARREL DISTORTION:
ROPING:
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DRIFT: These effect appear as unwanted motion in horizontal
lines due to electronic component drift over time and image
moves up in very slow motion.
JITTER: This is caused by unwanted electronic signals thatcause the image to jump.
SWIM: Swim is another form of drift where shadow image
sort of appears.
SHADOW MASK: A tiny hole and is located just behind thescreen to guide the electron beam to strike one of the three
phosphors in a triad.
DEGAUSSING:Its a circuit that removes unwanted magnetism
from the monitor so that no deflection is there. MONITOR EMISSIONS: Monitors generate electromagnetic
radiation which falls into two category,
VLF 2KHz to 400KHz
ULF 2Hz to 5Hz
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Key Technology Issues
Pen Input Video And Image Display
Print output Technologies
Image Scanners
Digital Voice and audio
Digital Camera
Video Images and Animation
Full Motion video
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PRINT OUTPUT TECHNOLOGIES
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PRINT OUTPUT TECHNOLOGIES
DOT
MATRIX
INK JET LASER LASER
PRINT
SERVER
COLOR
TECHNOLOGY 9 & 24 pin
matrix,
impact
printers
Ink jet laser laser Ink jet color
Object type Text Text ,graphics,
images
Text ,graphics,
images
Text ,graphics,
images
Text ,graphics,
images
Document
Type
Forms,
checks
All types of
documents
All types of
documents
All types of
documents
All types of
documents
Speed 50-300 cps 50-200 cps 4-16 ppm 8-30 ppm 1 ppm
DPI - 300 dpi 300-1600
dpi
300-1600
dpi
300-1200
dpi
Output
Quality
Reasonable Laser-like Excellent Excellent Reasonable
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IMPACT PRINTERS
DIASY WHEEL PRINTER
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DOT MATRIX
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Print Server Topologies:
location of a printer depends on convenience of the users. It
could be attached to user workstations, workgroup LANs or
as a central resource.
All shared printers need to manage their queue very
efficiently.
Text is sent to printers in ASCII form and is converted to a
bitmap by the printer electronics, bitmap graphics is sent
exactly as it is.
Printer drivers are the files that control the actual operation
and facilitate all applications to use printer.
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DYE SUBLIMATION PRINTER
It has a thermal printing head with thousands of very tiny
heating element, each of them can be heated to one to 256different temperature under program control.
The cyan panel is rolled under the thermal printing head
first, this subjects the cyan ink to a high temperature and it
sublimates and attaches it self to paper making small dots.
The intensity of the dot depends on the temperature.
This is then repeated with Magenta, Yellow and then Black.
These printers are used for printing high quality multimedia
color images, and has immerged as a cheap alternative ofphotograph
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COLOR PRINTER TECHNOLOGY ISSUES
Many applications use International de lEclairages CIE XYZ
color model. It provides a mathematical representation of all
visible color and hardware is independent.
Still a device-independent color model does not works well in
practice for the following reasons:
1)Monitor use RGB model where as printers print in CMYK.
2)Color range of each technology is different.
3)Even after calibration, the color vary when printed.
POST PRINTING PROBLEM:
1)Dithering allows blending color; yet many colors never blend.2)Some times unpleasant dots called Moire pattern.
3)Color printing requires multiple pass which may result bad.
4)Color look different on different medium.
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Key Technology Issues
Pen Input
Video And Image Display
Print output Technologies
Image Scanners
Digital Voice and audio
Digital Camera
Video Images and Animation Full Motion video
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IMAGE SCANNER
CHARGED COUPLED DEVICES: All scanners use CCD as their
photo sensors. It consists of cells arranged in a fixed array,
cells are charged by intensity of light, which depends on the
pixel shade in the document.
The bright light that is emitted during the scan is used for
charging CCD and the charge is then measured by an analog
to digital device.
The binary value for the charge can range from 1 bit/pixel to
16 bit/pixel.
CCD extremely linear and sensitive to small change. They give
good result even if the document is not very clear.
It can operate under a wide spectrum of frequencies and has
high noise resistance.
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FLATBED SCANNERS
ROTARY DRUM SCANNER:
Transport
DRUM
Scan Position 1
Front PageScan Position 2
Front Page
Rotary Drum Scanner Construction
Handheld Scanners
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Handheld Scanners :
They can scan area is about 3 to 6 inches. S/W allow a page
to be scanned in two passes and reconstructed in software
to provide the same function as a full-page scanner. It can be used for surfaces that are curved and they also cost
less.
Unsteady movement may cause skewing, poor registration,
and improper alignment.
Color capturing in CCD
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Color capturing in CCD
Mirror
Lens
C
C
D
Mirror
Document
Moving
Three
Color
Lightsource
C t i l i
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Capturing color using scanners
Two approach are there
1) In first all three light source are switched on and therequired source is filtered and one component captures 4
bit (12 bit/pixel) or a true color image captures 8 bit(24
bit/pixel).
2) In second approach three lights are switched in sequence
and the CCD captures the component one by one.
Three CCDs are used to capture the information and then it
is been send to the memory.
HALF TONES: A black and white photograph is an image
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HALF-TONES: A black-and-white photograph is an image
built with a large number of shades of grey, that is with a
continuous tone.
Half tone is the technique to produce grey only by usingblack and white dots that vary in size.
DITHERING P i t i t i i l d t b t d t
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DITHERING:Printers print in pixel or dots but scanners dont
scan in dots so the scanners scan a group of pixels together
in a different pattern to approximate half tone patterns.
It is used to approximate shades of grey by varying thenumber of dots printed on the screen, the dark areas are
represented by many black dots where as light area by fewer
black dots.
Key Technology Issues
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Key Technology Issues
Pen Input
Video And Image Display
Print output Technologies
Image Scanners
Digital Voice and audio
Digital Camera
Video Images and Animation
Full Motion video
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DIGITAL VOICE Importance of voice:
How is this voice been converted into digital form. ADC converts voice into 8 16 or 32 bit digital value, this
determines the resolution of the voice.
ADVANTAGES:
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ADVANTAGES:
It requires times less effort than other ways of
communication
Low or unskilled people can also use them
Adds more life to the system specially in case of multimedia
Warnings and error messages can be delivered in a better
way
Disadvantage:
The accent in some cases is a hurdle for the system.
Existence of local words.
Needs expensive hardware. Similar sounding words.
V i R iti S t
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Voice Recognition System
SEPARATION BETWEEN WORDS
SPEAKER DEPENDENCY AND SPEAKER-INDPENDENTRECOGNITION
USE OF PHONEMES
VOCABULARY SIZE
Word Separation
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Word Separation When we speak discrete words we give a pause of 100ms to
500ms
This reduces up to 50ms in continues speech.
Therefore in such condition its almost very difficult to
recognize the end of a word and beginning of next word.
S k d d t d i d d t
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Speaker dependent and independent
recognition
(SD)In speaker dependent it recognizes the special
characteristics of the speaker, and it needs training(how??).
Normally this type contains few thousand words only, and
can not be used by other person.
(SI)Does not needs any training, but has large vocabulary.
Needs training from different people.
Use of phonemes
Dynamic binding at time of conversion. Phonemes reference pattern
Similarity is observed.