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Review of Literature

The literature review on this dissertation is reviewed on the various key areas related to the development of an extensible British Sign Language dictionary and Finger Spelling tool. This includes on detailed study on the topic of deafness and hearing impairment, Sign Language and its elements, various types of Sign languages followed in different countries, British Sign Language, Dictionary, Finger Spelling, Sign Supported English (SSE) and Visual Internet chat system. It also explains the technologies used in the Dictionary such as the Virtual Human Animation, Video based Signing system, Avatar based Signing System. Finally It explains on the tools used in developing the system, consists of JA Signing, Lingua Sign, and HamNoSys.

Technical Background of the Proposed System

The most essential and elementary form of the human interaction is the communication. The common form of communication between deaf communities is the Sign Language. It is the form of transmission of information from one person to another through medium of signs. The Sign Language has developed tremendously in recent days and well progressed through its several innovative technologies [Naqvi et al., 2005]. Sign language uses different digital techniques one among them is the sequence of signing in video systems. These sign sequences videos are broadly used in the television channels and Internet dictionaries. Various softwares such as Mak Messenger, Virtual Human and E-sign etc have been developed with the use of the signing notations such as Makaton, SignWriting, and HamNoSys [Zwitserlood et al., 2005]. The recent development in the Sign Language is the virtual human signing which replicates the human by Avatars. These Virtual Human Animation systems have been almost unwrapped many possibilities of communication by bringing the information on signing as closer to the visual nature of sign language. The Applications of the Virtual Human Animation is brought into existence by undergoing several extensive evaluation and various investigations and by further enhanced improvements of the quality. This virtual human animation has been applied in various applications; this includes the weather forecasting, bank, and the post office. On considering the post office it helps the signing person by translating the speech of post office clerk into the sign language and display to the person using the avatar.(signing for deaf) Thus, in order to provide an extension to the Signing system, an online BSL dictionary and finger spelling tool is developed with a help of the virtual Human Animation. The Online BSL dictionary is a digital representation of sign language which uses both the avatar and streaming video in alphabetical and various contexts. It mainly targets both the hearing and deaf audience who has no prior knowledge of sign language and act as a reference guide.

Deafness and Hearing Impairment

In general, deafness occurs as the result of damage in the parts of the ear [Ow et al., 2007]. In order to define it technically, deafness refers to the loss of hearing ability from one or both ears, right from the birth. It also results in the damage of inner, outer or any part of the ear. Hearing impairment on the other hand refers to the complete, fractional or partial loss of hearing ability from one or both ears and its level of impairment can be vary according to its severity it may be mild, moderate, severe or profound [Lim, 2008]. Hearing Impairments can be varied according to its nature.

A deaf person faces a lot of barriers in order to communicate. Below are the lists of barriers faced by deaf people in their life.

They face a serious problem by physically and also lead to some mental pressure which causes them not to lead a normal life.

Everything around us is based on sound, but it is unable for them to live with this sound which pushes them to a stress level of life.

They are highly dependent on the machines or an interpreter for communication or even to express their own thoughts.

These problem faced by them is not a transitory it is an everlasting disability.

It may not encompass them with alternative organs such as replacement of heart etc. it is a matchless disability which leads them to a great struggle by affecting their lives from birth to death.

Studies shows the fact that signing came into existence and widely spread into the deaf world only after 20 th century, Still there are lot many people who are unaware of this signing technology [Turner, 2000].

Sign Language

Sign Language is a visual-spatial language, which involves the portions of the body includes the hands, the face, eyes and mouth as a separate articulators [Lim, 2008]. To define, the Sign Language is more complex system than the spoken language consisting of more than a thousands of signs in which each of them has their own variance from the other by the minor changes in the motion of the hands, shape and the varying positions. (1) It is a rich language comprises of grammar and lexicons and entirely different to that of English. Sign language mainly involves of four elements for signing. It constitutes the forms of hand, movements, Location they held and finally the orientation [Filhol et al., 2006].

There are four signing components are group together to form a Sign Language. These elements are explained in detail as below.

1. The Hand Shape sign element is the foremost element which is based on the shape of the hand while signing.

2. The positional orientation of the palm such as palm up or down gives the structure to the signing.

3. The movement of the hands forms the sense for signing.

4. Finally the position of the hands as it rests brings the message of the word.

Thus all these four postures jointly form a Sign Language (6).

Apart from this there also some important element in the sign language communication it constitutes the facial expressions and the association of hands. As the face shows the emotions of the words and association of the hands presents the structure of the word and in turn enhancing the communication [Ohene-Djan et al., 2003]. In the last thirty years, sign language has become the standard way of guidance to the deaf people and also for deaf children. Sign language helps the deaf children to communicate well with both hearing and deaf people. It is also evident from the studies that they possess excellent communication skills unlike their superiors only with the help of using sign language [Ohene-Djan et al., 2003]. The figure below represents as how the signs are clearly explained by the four signing elements, facial expressions and Association of the hands [Vinson et al., 2008].

Types of Sign Languages

There are various types of sign language followed by almost all the countries. Studies show that the efficient communication between the deaf people and the normal by means of signing and human gestural system has almost made it used extensively by all the countries though it is not a universal language. Though it is used almost in all the countries the most common among the sign languages is the American Sign Language (ASL), the British Sign Language (BSL) and the Auslan Sign Language.

British Sign Language (BSL)

The sign language which is in general designed for the people of United Kingdom and in Scotland is termed as the British Sign Language (BSL). The British Sign Language (BSL) is the most preferred language used by almost all communities of hearing impaired and deaf people in the UK. It conveys the meaning of the words by using the features such as hands, facial expressions and head movements. It is a highly visual language which has developed over many hundreds of years in order to meet the needs of deaf people to interact with each other and to the normal people. BSL is not entirely based on the English Language but has a different structure to English. As each sign language does not have corresponding matching word in English, BSL has its own set of grammatical structure. It is a visual language which is constantly developing and changing, as does by every living language. It has been estimated that nearly 70,000 deaf people in the United Kingdom, between 50,000 and 100,000 people in the UK, uses the BSL as the main language [Turner, 2000]. It is also found that British sign Language is the fourth indigenous language [Kyle et al., 2005].There are other non-BSL forms of sign language which include Cued Speech, Paget-Gorman Sign System, Signed English and Sign Supported English. These may include the use of speech. These forms do not represent the natural language of deaf people and are usually used for educational purposes. The figure below illustrates the Signing for the word "Weather" in British Sign Language [BSL, 2009].

Forms of the BSL Sign Language

Signed English

Signed English is a form of the British Sign Language which is the parallel representation of the spoken English manually. Signed English is mainly designed for the deaf community children’s in order to educate them the English Language and the core of the Language such as Grammar by means of the signs. This Signed English method can be applied to various languages other than English. It is a simple and attractive way of communication that makes the children to learn easier. (signed English reference)

Sign Supported English (SSE)

British Sign language has another form called Sign Supported English (SSE).Sign Supported English (SSE) is commonly used in Britain [BSL, 2009].SSE is basically not a language by itself.SSE uses the same signing as of that of British Sign Language but they are used in the same way as English spoken. SSE is mainly used to support children's with hearing impairments by helping them with the training in spoken English, and the English grammar with the help of signing.

Finger Spelling

British Sign Language constitutes of one of the similar technology in the Sign Communication, constitutes the Finger spelling which is the technology used to interpret the sign language with a medium of hands and fingers. Finger spelling interpretation is triggered with the help of hand shapes i.e. it is used to spell the words letter by letter through signs for recognition of the signs and clear view of sign for an individual alphabet [BSL, 2009]. It is also illustrated as an individual display of letters in hands in order to spell out proper names or locations. Though it was developed by the committee of the hearing people for the deaf it has been developed and evaluated based on the complete research by understanding the difficulties, where it plays a major role in the interpretation of the sign language. It requires the Basic knowledge in Signs of the alphabet A-Z as it basically contains only the letters. There are two forms of the Finger Spelling, constitutes the Right-Handed Finger Spelling and the Left Handed Finger Spelling.

Finger Spelling is used to perform the signing a letter by operating the hands towards the raised and a comfortable position by bending the elbow [Jerde et al., 2003]. When the arm is protected at a stationary position it is said to be the performance of finger spelling [Lim, 2008]. It is most frequently used to interpreting the word by alphabets for the word clarifications and for the precise names, such as a name of the person, the streets name etc. The figure below illustrates the working of finger spelling of by depicting the hand shapes which represents the Alphabets [Sutton-Spence et al., 2008].

Visual Internet Chat System

Visual Internet Chat System is a future extension of the Sign-Language enables the deaf users to make use of the Internet mode of communication. There are several Real-time communications technologies which include mainly the text, voice, video chat, and teleconferencing is increasingly being used by enabled users to communicate and to share information. As displeasure we cannot find such technologies for the deaf people. Though it has some it was not successful. There has some existence such as Mak-Messenger but the result is very limited with some drawbacks in the technology [Verlinden et al., 2005]. Thus this visual Internet chat system is aimed to propose the extensive chat system to the deaf communities which enable them to exchange their ideas by communicating visually with the help of signs and with some animating avatars.

British Sign Language Dictionary Tools and Technologies

British sign language Dictionary

Online sign language dictionary is mainly aims to support and to educate the deaf community. This Dictionary based education system is been suggested by many Researchers and analysts as they consists of the collection of resources of more than several thousands of English words. In short in can educate them by the search of the user query by presenting the sign videos. It consists of highly sophisticated learning technologies that make use of recent adaptive strategies together with it such as avatars video, which is been attracted by most users especially the kids that make them to learn by means of its positive influence. There are various online BSL dictionaries are currently in use that act as a well-known guide to the Sign Users. Educational tools are also available online that use these digital representations of sign language, There are also several Dictionary based tutorial systems for the kids such as Kids Sign Online (Ohene-Djan, J., et al, 2004 ) that uses these video to develop an interactive way of learning environment in order to teach sign language, and sign writing (Sutton,1996 ).

Technologies in Developing the Sign based system

Virtual human signing system

Virtual Human Signing system is generally developed to animate the Sign Language. This system helps to convert the contents of the information and present it by interpreting as signs. Virtual human signing involves the development of expressive Signing characters such as avatars. As due to the problems faced by the deaf people for information finding in the text, the same information is presented in the form of human animation and avatars.

Video based signing system

This video based signing system is generally the traditional way of the human signing system. Although it is the conventional way in the Sign language it is the most accurate and efficient way in depicting the signs as it produces the same result as how it is produced by the human’s sign. Though there are some recent developments exists in this system it is not extensively used as this video-based signing is widespread among several countries. For example though BSL is now implemented the Avatar based signing systems, this technology is not put into practice in the Auslan Sign Language which still follows the traditional video based signing.

Sign Language Animation System

Sign Language animation method can be possible by means of a motion capturing system. The motion capturing is the technology in which the real signer who present the signing for a complete sentence which split the signs into individual by an motion capture suit which is illuminated and gets separated by the three separate data streams which in turn connected to the motion capture stream and synthesized into a single motion-data stream which is animated and produced as an virtual human an `avatar' directly. This is a motion capturing system for producing the Avatars which in turn known as the Sign Language Animation. The main a drawback of motion capturing is that it is labour intensive and requires expensive equipment [Glauert et al., 2009]. An alternative to motion capturing is a synthetic creation of animation which uses the SiGML based signing system.

JA Signing

JASigning which is known as the Java ARP Signing is generally a Synthetic sign language performance system, which is an recent advancement in the virtual human Signing system. It dominantes the SiGML Signing system by creating the Avatar based on the Java based ARP tool kit which was developed during the ViSiCAST and eSIGN projects.

Avatar based signing system

Avatar based signing system have been developed in recent years as this system produces the permit to control the animation content by using a range of avatars embedded in a wide range of applications which also have the facility to include with the help of the extensive support on the web pages [Glauert et al., 2009]. This is done by an integration of framework by SiGML processing through Animgen, and supports a number of avatars developed. The real virtual avatar video has numerous applications in the British sign language. It forms a part of the virtual signing project.

British sign language consists of two types of the Avatars, where the first is developed by the Motion capture system with the help of the sensors. It has been evaluated and successfully implemented in Real time applications. The second type of avatar has been developed based on the synthetic signing with the SiGML notation systems which also replicates the facial movement through the audio which motivates them to lip read which helps them to improve the hearing capability.

Tools used in the development of the Sign based systems.


SiGML (Signing Gesture Markup Language) was initially developed in the ViSiCAST project as a key component of a prototype "natural language- to-signed-animation" system project and it is used to generate realistic animation of signing using Virtual Human Avatars [Glauert et al., 2009]. It is a syntactic representation to facilitate computer processing for the Animation of signing. Thus the Key purpose of SiGML is to support the characterization of signing gestures in a manner allowing them to be animated in real-time using a computer generated virtual human character, or avatar.

The Animgen

The AnimGen involves the synthetic Signing system as it utilizes the most advanced techniques for skeletal animation in order to realize well defined hand shapes and movements, leading to accurate body contacts [Glauert et al., 2009]. In addition, to the skeletal animation it also includes a range of facial gestures is animated by weighting morph targets giving appropriate displacements for facial mesh points. AnimGen, requires a number of configuration files for each avatar that contain skeleton specific data to achieve correct arm movement and hand shapes [Glauert et al., 2009].


HamNoSys is practically a formal model in the signing systems which is a pictographic notation used for deaf signing mainly used for the software in generating the signs. Hamnosys is based on Stokoe's 4-parameter model comprising of

1. The Hand Shape sign element is the foremost element which is based on the shape of the hand while signing.

2. The positional orientation of the palm such as palm up or down gives the structure to the signing.

3. The movement of the hands forms the sense for signing.

4. Finally the position of the hands as it rests brings the message of the word. [Kennaway, 2002]. It has the same parameters for every signs. It is designed in such a way as it is not in the human understandable form. It is also presented as it cannot be read the machines nor the computer system. The purpose of HamNoSys is to support the transcription and analysis of human signing in a manner that is independent of the particular sign language used by the signer. The figure below is a sample of a HamNoSys notation [Kennaway, 2002].

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