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Multimedia Systems Design A Picture is worth of thousand words

- Basic idea behind the data representation inMultimedia

What constitutes Multimedia?

At the start of 1990, Multimedia means acombination of text with document images.

During this period, Document Image Managementwas an outgrowth of facsimile technology.


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Multimedia Systems DesignWhat is Facsimile technology?

Facsimile provided a means of scanning andconverting a document into coded information that describedeach pixel as white or black. When the pixel intensity was

low, information was easily readable.. When pixel intensityincreased that are too dense information was not readable,so fax machines were developed..

Different coding techniques were developed such as Run-length encoding and Huffman encoding for compression of

data for processing in fax machines. Two organizationsnamed CCIT (International Consultative Committee forTelephone and Telegraph) and NTSC (North AmericanTelevision Standards)


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Multimedia Systems DesignConferencing Technology

A number of categories from basics of conferencingtechnology including text, conversations, documentconferencing (or shared white boards), and live or store-and-

forward video conferencing are introduced these days for thebetter communication.

One common theme in all these approaches isinteractive electronic mail. A development in this field during1990s is desktop video conferencing (this allows users to

video conference from their own desks rather than having togo special conferencing facilities)

A key to the success of video conferencing will be ability ofsystems to open with sophisticated networking capabilitiesand to have good compression and decompression

capabilities.


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Multimedia Systems DesignA key to success of the video-conferencing will be the ability

of systems be open with sophisticated networkingcapabilities and to have good compression anddecompression capabilities. Video conferencing is just

one multimedia application. A wide range of newapplications are in use or under development.

a. Medical applications such as analysis of surgicalprocedures and high resolution x-ray imaging.

b. Real estate on-line video clips with propertydescriptions.

c. Multimedia help and training material.d. Security systems for employee identification


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Multimedia Systems DesignMultimedia Elements

a. Facsimile

b. Document Images

c. Photographic Images

d. Geographic Information System Maps

e. Voice Commands and Voice synthesis

f. Audio Messages

g. Video Messages

h. Full motion stored and live video

i. Holographic imagesj. Fractals


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Multimedia Systems DesignAbout Different Elements of Multimedia

1.Facsimile: Facsimile transmission is also known as run-length encoding is a medium level of compression thatcan be easily achieved in software. It has been

estimated that for a reasonably true representation andacceptable legibility a 200 dpi is essential, which iscontrasting with laser printers which supports maximumof 400 dpi. This follows CCITT Group 3 compressionstandards

2. Document Images: for serious storage of document

images in electronic form with adequate reproductionquality the requirement starts at 300 dpi. Group 4compression standards are followed in this formatwhich reduces the size to 75 kbytes which less than anuncompressed A-Size (8 inch X 11 inch) image. Thegoal of document imaging is to seriously image textbook size of data


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Multimedia Systems DesignAbout Different Elements of Multimedia

3. Photographic images: Photographic images are usedfrequently for imaging systems that are used foridentification such as security badges, fingerprint cards,

photo identification systems, bank signature cards,patient medical histories, and so on. The requirementsof photographic images are much more intense thanthose for typed documents. Photographic imagesrequire proper handling of soft shades and tones. Aresolution of 600 dpi is essential for reproducing aphotographic image on a laser printer. High resolutionsare preferable.


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Multimedia Systems Design7. Video Messages: Similar to audio messages, VideoMessages can be embedded in or attached to e-mailmessages. Video messages can range from singlesnap shot to full motion video clips. The storage andplayback requirements are even more complex forvideo messages.

8. Full motion stored and live video: CD ROM technology hasprovided the basis for the development of full motionvideo. Some of the applications include CD-ROMgames, courseware, training manuals, multimedia on-line manuals and reference material etc. An important

consideration for full motion video is the need for largeband widths for communication media, massive storagerequirements and high-density performancecompression technologies. Various standardizationtechniques are used for the above purpose and theefforts are still in progress.


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Multimedia Systems Design9. Holographic images: Holography is defined as the means of

creating a unique photographic image without the use of lens.The photographic recording of the image is called hologram,which is an unrecognized form of pattern of stripes and whorlsbut which when illuminated by coherent light as by a laser

beam, organizes the laser light into a three dimensionalrepresentation of the original objects. Holographic imagesextend the concept of virtual reality by allowing the user to getinside a part such as engine view and its operation from theinside.

10. Fractals: Fractals started as technology in the early 1980s but

has received serious attention only recently. This technologyis based on synthesizing and storing algorithms that describethe information. Fractals are regular objects with a highdegree of irregular shape. Fractals are the decompressedimages that result from a compression format that usesarithmetic algorithms to define repeated patterns in the image.


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Multimedia ApplicationsWith the progression of graphical user interfaces opened theway of variety of multimedia applications, document

image management is the first widely used application

that requires storage of large volumes of data in

document image format. Document image managementstill plays a major role most office applications based on

a multimedia system.

Image processing also known as image recognition is a very

different application, while document image

management is primarily intended for scanning

documents and retaining their images, image

processing and image recognition are intended for

recognizing objects by analyzing their raster images.


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Multimedia ApplicationsThe other applications include E-messaging and Full-motionDigital Video Applications (which includes full motion

video messages).


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Multimedia Applications (in detail)

1. Document Imaging

The first major step toward multimedia systems, was

originated in document image management.

Organizations such as insurance agencies, law offices,county and state governments, federal government

including Department of Defense manage large volume of

documents.

Technologies developed for imaging are an indispensable

ingredient in the applications that will evolve to create theefficient combination of text, image, sound and video for

attractive target called multimedia.


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Document imaging makes possible to store, retrieve and

manipulate very large volumes of drawings, documents

and other graphical representation of data. Imaging also

provides an important benefit in terms of electronic data

interchange.

Document imaging is getting the boost from the increasing

power in desktop workstations and PCs as well as from

standardization of higher-resolution display

technologies.

A minimum of 100 dpi is necessary for a typical A size

document.


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Imaging is already being used for a variety of applications.

An application such as medical claims processing not

only speeds payment to healthcare facilities, but cuts

cost of reentering information from claim forms into

computer database.Optical character recognition systems now automatically

handle the task of data entry of key fields.

In document imaging, the primary reason for scanning at high

resolution and storing image at high resolution is able toprint them on high resolution laser printers ranging from

300 to 600 dpi capability.


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In determining storage levels for these type of images

compression algorithms are very important. A

compression efficiency of 20:1 considered highly

desirable for document images.

Document Image Hardware requirements

Real-time image decompression and display place

special demands on image processing hardware.

Typically the decompression supports 4 to 8 planes,

The image planes are also called bit planes becausethey are addressed by a bit in a byte.

For acceptable responses, images must be processed at the

rate of tens to hundreds of pixels per nanosecond

(pixels/ns).


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For monochrome/still images, the image processing is done

in order of 10 pixels/ns.

For grayscale images, high speeds are required due to the

size of image. The grayscale images consists of pixelsthat have the shades of gray ranging from 16 to 256,

depending on the implementation.

For colored images, like grayscale images high speeds are

required due to features of color hues instead of shadesof gray. Most resolutions support 16 to 256 colors

display capability. The number of colors that can be

depicted depends on the number of bits used to define

the palette.


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2. Image processing and Image recognition

Unlike document image management, image

processing involves image recognition, image

enhancement, image synthesis and image

reconstruction.

The original image is not altered in a document image

workflow management system; rather annotations are

recorded and stored separately.

An image processing system, on the other hand may actuallyalter the contents of image itself.


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Image synthesis and reconstruction systems may use

combination of bit maps and complex arithmetic

algorithms to calculate drawing entities, including shading

and color variations.

Image processing systems may combine the technologies of

full-motion video with images. Video camera output forimaging requires special processors to perform optical

recognition on images at high speed.

Image recognition exists in many forms. Optical character

recognition (OCR) constrains the general imagingproblem to specific applications area such as recognition

of printed characters. Handwriting recognition is used by

the Post office for recognition of hand written zip codes

for mail sorting.


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Image Enhancement

Most image display systems feature some level of imageenhancement. The enhancement may be increasing the

sensitivity and contrast which makes the picture darker by

making borderline pixels black or increasing the gray-

scale level of pixels.

Some of the capabilities in image enhancement include

Image calibration- i.e. image pixels are adjusted to apredefined level.

Real-time alignment- image is aligned (i.e. rotated by

small angles) in real time for skewing caused by improperfeeding of paper.

Gray-scale Normalization- the overall gray level of imageor picture is evaluated to determine if it is skewed in onedirection or if needs any correction


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RGB hue intensity adjustment- Too much color makes picture

garish and fuzzy. Automatic hue intensity adjustment

brings the hue intensity within predefined ranges.

Color separation- A picture with very little color contrast can be

dull and may not bring out the details. The hardware used

can detect the range of color separation.

Frame averaging- The intensity level of the frame is averaged

to overcome the effects of very dark or very light areas by

adjusting the middle tones.


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Image Animation

Computer-created or scanned images can be displayedsequentially at controlled display speeds to provide image

animation that simulates real process. The multiple bit

plane capability of decompression and display hardware

is to decompress and save successive images in

successive bit planes.

Image animation is a technology that was developed by Walt

Disney and brought into every home in the form of

cartoons.

The basic concept of displaying successive images at short

intervals to give the perception of motion is being used

successfully in designing moving parts such as

automobile engines, such as designing parts and

modeling parts in CAD/CAM systems.


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Image Annotation

Image Annotation can be performed in one of two ways

a) as a text file stored along with the image or as a small

image stored with the original message. The annotation is

over layed over the original image for display purposes.

b) requires tracking multiple image components

associated with a single page, decompressing all of them,

and ensuring correct spatial alignment as they are over

layed.


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Handwriting Technology

Handwriting recognition has been the subject of intenseresearch for a long time. Originally this research was

performed for CAD/CAM systems for command

recognition.

The key design considerations in handwriting recognitionsystems are the ability to recognize writer independent

continuous cursive handwriting accurately in real time.

Handwriting recognition engine uses complex algorithms

designed to capture data in real time as it is being input or

from an image displayed in a window, depending on theapplication.


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Two factors are important for handwriting recognition: the

strokes or shapes being entered.

The strokes are parsed and processed by shape recognizer

that tries to determine the geometry and topology of the

strokes. It attempts to compare it to existing shapes, such

as predefined characters, In matching these strokes best

guess approach may be used. The stroke is compared

with a prototype character set until a match is found on all

predefined prototypes have been checked without a

match.

In this approach, comparisons of predefined characters can be

very processing intensive.

Multimedia systems will use handwriting recognition as another

means of input. Handwritten memos using pen-based

machines may be interpreted and read-out when they are

part of a complex document or a mail message


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Non textual Image Recognition

verbal communication is the principal mode by which weexchange information, psychologists have long known

that our comprehension of facial expressions, posture and

gestures represents important and additional input which

plays a major role in interpersonal communication.

Practical applications in medicine, manufacturing, and security

systems are fueling a growing world wide interest in

image recognition which is not easy .

The other applications include full-motion digital videoapplications, full-motion video messaging and electronic

messaging.


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Multimedia Systems Architecture

Unlike most other systems, multimedia encompasses a large

variety of technologies and integration of multiple

architectures interacting in real time.

Another important aspect of multimedia systems is that all of

these multimedia capabilities must integrate with the

standard user interfaces such as Microsoft Windows, XWindows or Presentation Manager.

The design should be such that systems can operate with or

without special hardware needed for multimedia such as

DSPs with no change in the application software, theapplication should require more absolutely no change to

operate with a variety of hardware interfaces.


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Standardization has been afoot for a number of hardware

interfaces for video animation and compression boards.

The application is designed to operate with any hardware

or operating environment that supports API. Common file

formats allow data files to be exchanged between

hardware architecture and operating environments.

Standard device independent APIs are there to support a wide

range of applications in publishing and interacting with the

applications.

The developer builds support for driver for the supportedhardware. The APIs allow the application to support a

large number of drivers. This approach can work with

peripheral boards, software designed to replace hardware

components, and network interfaces.


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Software compression and decompression can replace these

hardware boards.

Use of common APIs allows application developers to develop

applications that can work with hardware drivers as well

as with software drivers. Use of software drivers allows

the user to interact with a much wider range ofperipherals and systems.

The following figure describes the architecture of multimedia

workstation environment. In this architecture diagram left

side is very similar to non-multimedia systems. The rightside shows the new architectural entities required for

supporting multimedia applications.


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APPLICATIONS

Graphical User Interface

Design Multimedia Extensions

Operating System Software Drivers Multimedia driver

support

System Hardware Add-on(Multimedia enabled) Multimedia devices and

Peripherals


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The add-on devices and peripherals include scanners, video

cameras, VCRs and sound equipment along with their

associated device controllers and encoding hardware

(such as DVI-JPEG or MPEG-encoded boards, for all

these devices special driver software is needed)

Multimedia operations places tremendous demands on the

system hardware, in terms of both computing

performance and storage.

The various graphics standards such as MCA, CGA, EGA,

VGA, 8514 and XGA have demonstrated the increased

demands for higher and higher resolutions for graphic

user interfaces. Increasing use of GUI applications based

on window managers such as IBMs Presentation

Manager, Microsoft Windows, MITs X windows have

placed special demands on graphic resolutions on

workstation display systems


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