multimedia input

8/4/2019 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


Print output Technologies

Image Scanners


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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Pen Input



Image Scanners


Digital Camera


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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Pen Input Video And Image Display


Image Scanners Digital Voice and audio

Digital Camera


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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Pen Input Video And Image Display


Image Scanners


Digital Camera


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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Pen Input



Image Scanners


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.



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Pen Input



Image Scanners


Digital Camera


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.

multimedia input

Documents