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On the manual transcription of braille
AppliedErgonomics 1977, 8.3,159-163
On the manual transcription of Braille B. Hampshire * and T. Whiston t • Handikappinstitutet, Bromma, Sweden; t Science Policy Research Unit, University of Sussex, UK.
Although innovations in the computerised production of braille have improved braille provision, there remains still a need for manual transcription of more complex and/or specialised material. Relatively little attention has been paid to improving this type of production despite the fact that the manual transcription of braille has two advantageous features - it utilizes a chord keyboard, and the input is encoded. Some implications and areas for future research and development are suggested. Introduction
The braille reading population
The system used for reading and writing by the blind which was developed by Louis Braille has now been in existence for 150 years. (Anon, 1975). For the first 140 years of its existence, braille was produced exclusively by manual transcription, ie, a person who knew the braille code rewrote the material in braille using a mechanical braille-writer or a stereotype machine, (a keyboard operated machine for writing braille onto folded metal sheets, which can then be used for pressing multiple copies of braille on paper).
The age structure of the blind population forms almost the mirror image of the general population. In the latter, those under 25 years comprise nearly half the population and those over 65 years account for a very small proportion indeed. In contrast, among the visually impaired, the elderly constitute a considerable majority of the population (60% are over 70 years old (Gray and Todd, 1968)), with relatively few of the young age groups. The main reason for this is simply that 'getting old' is often accompanied by failing eyesight.
The last decade, however, has seen considerable innovations and advances in the uses of computers to 'translate' inkprint into the braille code. This still, of course, requires the inkprint to be in a computer readable form, and the most usual way of doing this is to simply rewrite or keypunch the material onto punched cards or magnetic tape, or even directly on-line into the computer. More sophisticated techniques are also beginning to be used. For example, use of compositors' tapes obtained directly from the inkprint publishers are used to produce braille books in the Netherlands and a fortnightly magazine in West Germany. Optical character recognition as a means of input into the computer is also being explored. Although such developments have undeniably improved braille provision in certain areas, the almost total emphasis on the sophisticated, the high speed, and on 'high technology' generally, does not reflect the needs of the braille reading population completely, for reasons explained below. The result is that there is still a serious shortage of braille material for school children, students, and many of the blind employed in the professions requiring specialised and/or technical literature. Virtually all this area of production is still carried out manually, and has been largely unaffected by research and development in the area of braille production. Before discussing the role and (neglected) potential of manual transcribers, some description of the braille reading population and of the braille code would be illuminative.
This fact, combined with the complexity of the braille code (see below), and the consequent difficulty in learning to read it, (furthermore, if blindness has developed later in life there is considerable perceptual readjustment to make which adds to the initial learning difficulties), is mainly responsible for the very low use of braille by the blind population - of the order of 10% only. Not only does this mean that the production systems for braille material must cater for very small numbers - a production run of 100 copies of a book would be considered large, and runs of 20-30 copies are typical in England - but also, the needs for braille are not proportionally distributed across the age range. Thus, school children and students, although constituting a very small percentage (about 1%) of the visually impaired population numerically, nevertheless constitute a major segment of the market for braille material. This has important implications for braille production in that a large proportion of the braille material required by school children and students is of the kind that cannot yet be handled by computerised techniques. Production of material for this important market segment, therefore, is still dependent on manual transcribing techniques.
The Braille Code system Braille is based on a cell of six raised dots (three high by two wide), various combinations of which denote letters,
Applied Ergonomics September 1977
159
words, contractions (signs standing for two or more letters in a word), and punctuation. In addition, 78 words are abbreviated when written in braille. Thus, the 63 possible permutations of the braille cell are assigned a total of 201 'meanings' (in the Standard English Braille Code), some signs having to serve more than one purpose. For example, the sign for the letter 'E' is ". or dots 1 and 5. (The braille cell is conventionally numbered as follows I .. 4 2..5). 3..6 However, when preceded by dot 5 ( .'. ) the word 'ever' is denoted, when preceded by dots 4 & 6 ( ~". ) the suffix '-ance', when preceded by dots 3, 4, 5, &'6 ( i ". ) the number '5', and if there is a space before and'after it ( ". ), it denotes the word 'every'. To make things even more complex the rule system which governs when certain contractions can be used, cannot be completely defined operationally. For example, the English system contains the rules: "32. The contractions for BE, CON and DIS may be used only as syllables at the beginning of a word or of a braille l i n e . . . "178. Contractions (ie, upper contractions) should not be used which would upset the usual pronounciation of syllables... "200. The contraction HERE may only be used when the letters it represents are pronounced as one syllable with the 'H' aspirated, and when it is not followed by the letters d, n, or r . . . "201 .The contraction NAME may only be used when the letters it represents are pronounced as 'name'... " (National Uniform Type Committee, 1971) The task of developing braille translation software, and of training braille transcribers, is not a trivial one. Even now translation programs are not 100% accurate in their production of contracted braille; even 99-5% accuracy means 5 errors per 1000 words, which in a book of 50 000 words is 250 errors. Although this would not be particularly disruptive for ordinary print books because of the high redundancy of language (around 66%), it is more significant for braille because of its considerably reduced redundancy due to the contraction system. In addition to the code system for prose, there are special code systems for mathematics, science notation, music, etc, which often require complex formatting of the text as well. Furthermore, in Sweden, many of the books produced for school children only use certain parts of the contraction system for Swedish braille depending on each child's proficiency in braille, so that, in effect, each book is tailor made for each reader. Such sophisticated use of the contracted braille system as described above is, as yet, beyond the capabilities of existing braille translation software, although work on the development of such programs is proceding.
Sweden, Finland, and France - used exclusive manual transcription techniques; and West Germany used a computer in the production of one fortnightly magazine, but otherwise everything was produced manually. Of the three remaining countries surveyed, the UK, Denmark and the Netherlands, although they used computerised techniques (especially ir.~ the Netherlands where the general use of uncontracted braille eliminates many of the problems of computerised production), extensive use of manual transcription was still necessary. Also, in the USA, where computerised translation has been in operation for more than a decade, there is still a need for a widespread network of volunteer transcriber groups to cater for the demands for braille material. One of the main justifications for the research and development emphasis on computerised translation of braille has been the increasing shortage of skilled transcribers. This response to the declining numbers of transcribers is rather negative, in effect, saying: if sufficient transcribers cannot be found, how can we do without them altogether? There are, however, certain features associated with the manual transcription of braille that have considerable potential for exploitation, but these features are 'masked' at the present time by the conditions and equipment transcribers have to work with - in many cases essentially the same since the beginning of the century.
The potential of manual transcription: equipment design The keyboards on mechanical braillewriters and stereotype machines are chord keyboards. They consist, basically, of six character keys, each one corresponding to one dot of the braille cell, and a space bar. By pressing combinations of these keys simultaneously, all 63 braille characters can be produced. A recent review (Seibel, 1972) of data entry devices and procedures, which included a section on chord keyboards, concluded that "the potential of chord keyboard data entry is very high. Indications are that entry rates of 150% of standard typing are relatively easy to achieve. It is recommended that chord keyboard systems be explored more fully for data entry purposes . . . . " The present equipment available to transcribers does-not begin to exploit the potential high-speeds of chord keyboards. In common use in England, for example, especially by book transcribers, is the Stainsby machine (see Fig. 1) which can be fairly described as an 'ergonomist's nightmare'. It possesses the following features: • The keys require considerable effort to depress (2 to 3 times that required for an ordinary mechanical typewriter, assuming that the Stainsby is in good condition). • A long stroke movement, which has to be made in full and with pressure to obtain a satisfactory braille dot. • The hands must point inwards, towards each other, see Fig. 2), thus causing the elbows to be held up, and away from the body. An extremely tiring posture!
Current use of Braille transcribers
• The 'keyboard/embossing unit' moves, from right to left, along a rack, after each depression of the keys. The rack
Despite the innovations in computerised braille production, manual transcription is still in widespread use. In a survey of seven European countries*, three -
* Conducted by Hampshire while on a Winston Churchill Travelling Fellowship in June 1975.
160
Applied Ergonomics September 1977
Charocter keys
Releoseclip for 'corrioge return'
bar
ordinary briefcase, whereas a Perkins is more akin to carrying a rather bulky portable typewriter. A further unfortunate anomaly between these two machines is that the key arrangements are different. On the Stainsby the 3rd, 2nd, and index f'mgers of the left hand are used for the keys corresponding to the braille dots 1, 2, and 3 respectively. On the Perkins, the same f'mgers are used for dots 3, 2 and 1, respectively. The corresponding reversal exists for the right hand also. In a project to design a new braille production system for the National Library for the Blind in Manchester undertaken by the authors (Whiston, 1975), an improved braille keyboard was built which wrote onto punched paper tape. This tape could then be used to produce braille copy from an automated embossing device. The keyboard unit is illustrated in Fig. 3.
Fig. 1
The Stainsby braille writer
and keyboard/embossing unit are moved down one position on the base plate after each line has been completed. • The keys are small and smooth, thus it is easy for the fingers to slide off them while using the machine. Given, furthermore, the position of the arms, when this happens there is little that the operator can do to stop his hand falling painfully onto the upward pointing serrations of the ratchet mechanism along which the keyboard moves.
Although this keyboard has not yet been thoroughly evaluated because of unreliability in the output unit, initial comments by users, both blind and sighted, were extremely favourable. However, the detailed design of this keyboard may not be optimum as manufacturing constraints played a significant part in its design. Nevertheless, it was clear that the operators found it considerably superior to using either the Stainsby or Perkins, which suggests that there is considerable need for further work in this area. One aspect which is particularly deserving of some investigation and effort is the development of a well designed braillewriter which is genuinely portable (in an ordinary briefcase), capable of writing on both sides of the paper, and reasonably silent. Today, apart from the above braillewriters, the only
• The space key is located to the right of the right-hand set of keys. Thus, to press this key, the thumb of the right hand must be curled under the fingers of the right hand in order to reach it. An alternative technique is to take the fingers of the right hand off the keys, and move them to the space bar, then back again to the character keys. • The Stainsby is a downward writer. This is to say that the 'keyboard/embossing unit' moves from right to left embossing the braille downwards. This means that, in order to check what has been written, the paper must be removed from the base plate and turned over. This is in contrast to upward writers (eg, the Perkins, see below) which allows the braille written to be checked immediately by touch or sight. This machine has been in use since about 1905! Just under a decade ago the Americans produced a new mechanical braille-writer - the Perkins - which is also in fairly widespread use in England and all over the world. However, the Stainsby has two crucial features which will ensure its continued use. These are: • The Stainsby can produce interpoint braille, ie, braille that is written on both sides of the paper such that the dots of the cells on one side are written between the dots of the opposite side. This allows, obviously, much more braille to be written on each sheet of paper, which, given the bulk of braille books, is an important feature. The Perkins only writes on one side of the paper. • The Stainsby is more portable than the Perkins. The rack and keyboard/embossing unit are separate from the base plate on which the paper is fixed. As this base plate can be folded, a Stainsby can be fitted fairly easily into an
Fig. 2
Stainsby braille writer showing operating position
Applied Ergonomics September1977
161
not influenced by the substitution of short forms. This crucial result suggests the contention that the substitution process can be carried on while typing without slowing the keystroke rate." Thus, for the fully srmlea braille transcriber, keying speed should be increased in proportion to the decrease in the number of characters used by contracted braille compared to print - about 30% for contracted English braille. Unfortunately, the degree of complexity of the braille code (see above) makes it a rather long and difficult task to reach a stage of proficiency where encoding does not take up an appreciable amount of the keying time. In theory, there is considerable room for improvement in the braille code. In the most recent statistical analysis of the efficiency of braille contractions (Kederis et al, 1965) it was found that only 76 out of the 255 symbols that are represented by one- or two-cell braille characters occurred over 1000 times. (This was out of a word population of 291 000, in which the most frequent character - 'E' occurred 61 882 times). Of the braille contractions included within these 76 characters (22% of all contractions), they saved 75% of the total number of character spaces saved by all the contractions.
Fig. 3
Keyboard unit of the braille production system builtfor the National Library for the Blind, Manchester
means for writingbraiUe (and it is in very widespread use) is the so-called 'slate and stylus'. This is a type of 'mask' that can be fitted over a piece of paper within which are 'windows' to guide the writer where to emboss the braille cells. The embossing is carried out using a blunt stylus to press out each dot of the cell individually. Although this equipment is extremely portable and writing speeds achieved are perhaps faster than one might expect (especially in view of the fact that the braille characters have to be written back to front so that they are the correct way round when the paper is turned over), it really ought to be possible to devise something better.
The potRntial of manual transcription: encoded input Encoding the input offers considerable potential for speeding up transcription processes. The most well known example of this is, perhaps, the Stenotyping system which is used for recording the proceedings of courts of law. The 'good' Stenotypist can enter 200 words per minute (wpm), with claims for upper rates exceeding 300 wpm. These can be compared with a 'good' typist who can enter something under 100 wpm (Seibel, 1964). The Stenotype keyboard is also of the chord type, so it is not certain how much of these increased rates is due to encoding and how much to using a chord keyboard as opposed to a single stroke per character keyboard. However, in one study examining the effects of redundancy-reducing codes utilizing single character per stroke keyboards (Schoonard and Boies, 1975) it was found that "Keying rate, in terms of characters per unit time, was
162
Applied Ergonomics September 1977
Many proposals have been made for changing the braille code, the latest by Deuce & Tobin (1976), but these always meet with considerable resistance from users of braille, who tend to be extremely conservative when any new code changes are suggested. In view of this situation, a more immediately rewarding research direction might be in endeavouring to improve the rate of learning the braille code by investigating both the teaching and learning processes which occur today. Conclusion Although considerable attention has been paid to increasing braille provision by the development of technology, this attention has been focussed to a large extent on 'high technology'. As a result, manual transcription techniques and equipment have remained almost unchanged since the beginning of the century. Studies of keyboard equipment and use suggest that the manual transcription of braille has two important advantages over normal print transcription. Firstly, it utilizes a chord keyboard, and secondly, because the material is encoded by the transcriber, the number of keystrokes is reduced, and this should be without any loss of speed of keyboard operation if the transcriber is proficient with the code system. In view of these features, and a pressing need for the type of material, the production of which is better suited to manual transcription than to computerised translation, there is considerable need and scope for developing new equipment and techniques that will exploit the potential of manual transcription of braille rather better than present facilities allow.
References Anon 1975 AppliedErgonomics, 6. 4 , 2 3 7 - 2 3 8 . 1 5 0 Years of Braille.
Douce, J.L., and Tobin, M.J. 1976 Braille Automation Newsletter. February, 5-8. Discussion Paper on the Desirability of a Joint Project on the Braille Code, Extending the Use of Braille, and the Improvement of Reading Skills. Gray, P.G., and Todd, J.E. 1968 Mobility and Reading Habits of the Blind. Government Social Survey (SS386). HMSO: London. Kederis, C.J., Siems, J.R., and Haynes, R.L. 1965 The Education of the Blind. December. A Frequency Count of the Symbology of English Braille, Grade 2, American Usage. National Uniform Type Committee 1971 Restatement of the Standard English Braille System. RNIB; London.
Sehoonard, J.W., and Boies, S.J. 1975 Human Factors. 17, 2, 203-214. Short-Type: A Behavioural Analysis of Typing and Text Entry. Seibel, R. 1964 Human Factors, 6, 189-192. Data Entry Through Chord, Parallel Entry Devices. Seibel, R. 1972 Dafa Entry Devices and Procedures. In: H.P. Van Cott & R.G. Kincade (Eds) Human Engineering Guide to Equipment Design. Washington, DC. US Government Printing Office. 311-344. Whiston, T.G. 1975 Automatic Transcription of Braille. In: Proceedings of The Louis Braille British Conference on Research into Reading and Listening by the Visually Handicapped. Southern Regional Association for the Blind. Conference Report No 66.
CALL FOR PAPERS THE ERGONOMICS SOCIETY ANNUAL CONFERENCE 4 - 7 April, 1978 at the Cranfield Institute of Technology, Bedfordshire, England.
Papers are invited on all aspects of Ergonomics. Please send abstracts (300 words) as soon as possible to the Hon. Meetings Secretary, I A R Galer, Dept. of Human Sciences, University of Technology, Loughborough, Leics, U.K.
Applied Ergonomics Sep•mber 1977
163
On the manual transcription of Braille B. Hampshire * and T. Whiston t • Handikappinstitutet, Bromma, Sweden; t Science Policy Research Unit, University of Sussex, UK.
Although innovations in the computerised production of braille have improved braille provision, there remains still a need for manual transcription of more complex and/or specialised material. Relatively little attention has been paid to improving this type of production despite the fact that the manual transcription of braille has two advantageous features - it utilizes a chord keyboard, and the input is encoded. Some implications and areas for future research and development are suggested. Introduction
The braille reading population
The system used for reading and writing by the blind which was developed by Louis Braille has now been in existence for 150 years. (Anon, 1975). For the first 140 years of its existence, braille was produced exclusively by manual transcription, ie, a person who knew the braille code rewrote the material in braille using a mechanical braille-writer or a stereotype machine, (a keyboard operated machine for writing braille onto folded metal sheets, which can then be used for pressing multiple copies of braille on paper).
The age structure of the blind population forms almost the mirror image of the general population. In the latter, those under 25 years comprise nearly half the population and those over 65 years account for a very small proportion indeed. In contrast, among the visually impaired, the elderly constitute a considerable majority of the population (60% are over 70 years old (Gray and Todd, 1968)), with relatively few of the young age groups. The main reason for this is simply that 'getting old' is often accompanied by failing eyesight.
The last decade, however, has seen considerable innovations and advances in the uses of computers to 'translate' inkprint into the braille code. This still, of course, requires the inkprint to be in a computer readable form, and the most usual way of doing this is to simply rewrite or keypunch the material onto punched cards or magnetic tape, or even directly on-line into the computer. More sophisticated techniques are also beginning to be used. For example, use of compositors' tapes obtained directly from the inkprint publishers are used to produce braille books in the Netherlands and a fortnightly magazine in West Germany. Optical character recognition as a means of input into the computer is also being explored. Although such developments have undeniably improved braille provision in certain areas, the almost total emphasis on the sophisticated, the high speed, and on 'high technology' generally, does not reflect the needs of the braille reading population completely, for reasons explained below. The result is that there is still a serious shortage of braille material for school children, students, and many of the blind employed in the professions requiring specialised and/or technical literature. Virtually all this area of production is still carried out manually, and has been largely unaffected by research and development in the area of braille production. Before discussing the role and (neglected) potential of manual transcribers, some description of the braille reading population and of the braille code would be illuminative.
This fact, combined with the complexity of the braille code (see below), and the consequent difficulty in learning to read it, (furthermore, if blindness has developed later in life there is considerable perceptual readjustment to make which adds to the initial learning difficulties), is mainly responsible for the very low use of braille by the blind population - of the order of 10% only. Not only does this mean that the production systems for braille material must cater for very small numbers - a production run of 100 copies of a book would be considered large, and runs of 20-30 copies are typical in England - but also, the needs for braille are not proportionally distributed across the age range. Thus, school children and students, although constituting a very small percentage (about 1%) of the visually impaired population numerically, nevertheless constitute a major segment of the market for braille material. This has important implications for braille production in that a large proportion of the braille material required by school children and students is of the kind that cannot yet be handled by computerised techniques. Production of material for this important market segment, therefore, is still dependent on manual transcribing techniques.
The Braille Code system Braille is based on a cell of six raised dots (three high by two wide), various combinations of which denote letters,
Applied Ergonomics September 1977
159
words, contractions (signs standing for two or more letters in a word), and punctuation. In addition, 78 words are abbreviated when written in braille. Thus, the 63 possible permutations of the braille cell are assigned a total of 201 'meanings' (in the Standard English Braille Code), some signs having to serve more than one purpose. For example, the sign for the letter 'E' is ". or dots 1 and 5. (The braille cell is conventionally numbered as follows I .. 4 2..5). 3..6 However, when preceded by dot 5 ( .'. ) the word 'ever' is denoted, when preceded by dots 4 & 6 ( ~". ) the suffix '-ance', when preceded by dots 3, 4, 5, &'6 ( i ". ) the number '5', and if there is a space before and'after it ( ". ), it denotes the word 'every'. To make things even more complex the rule system which governs when certain contractions can be used, cannot be completely defined operationally. For example, the English system contains the rules: "32. The contractions for BE, CON and DIS may be used only as syllables at the beginning of a word or of a braille l i n e . . . "178. Contractions (ie, upper contractions) should not be used which would upset the usual pronounciation of syllables... "200. The contraction HERE may only be used when the letters it represents are pronounced as one syllable with the 'H' aspirated, and when it is not followed by the letters d, n, or r . . . "201 .The contraction NAME may only be used when the letters it represents are pronounced as 'name'... " (National Uniform Type Committee, 1971) The task of developing braille translation software, and of training braille transcribers, is not a trivial one. Even now translation programs are not 100% accurate in their production of contracted braille; even 99-5% accuracy means 5 errors per 1000 words, which in a book of 50 000 words is 250 errors. Although this would not be particularly disruptive for ordinary print books because of the high redundancy of language (around 66%), it is more significant for braille because of its considerably reduced redundancy due to the contraction system. In addition to the code system for prose, there are special code systems for mathematics, science notation, music, etc, which often require complex formatting of the text as well. Furthermore, in Sweden, many of the books produced for school children only use certain parts of the contraction system for Swedish braille depending on each child's proficiency in braille, so that, in effect, each book is tailor made for each reader. Such sophisticated use of the contracted braille system as described above is, as yet, beyond the capabilities of existing braille translation software, although work on the development of such programs is proceding.
Sweden, Finland, and France - used exclusive manual transcription techniques; and West Germany used a computer in the production of one fortnightly magazine, but otherwise everything was produced manually. Of the three remaining countries surveyed, the UK, Denmark and the Netherlands, although they used computerised techniques (especially ir.~ the Netherlands where the general use of uncontracted braille eliminates many of the problems of computerised production), extensive use of manual transcription was still necessary. Also, in the USA, where computerised translation has been in operation for more than a decade, there is still a need for a widespread network of volunteer transcriber groups to cater for the demands for braille material. One of the main justifications for the research and development emphasis on computerised translation of braille has been the increasing shortage of skilled transcribers. This response to the declining numbers of transcribers is rather negative, in effect, saying: if sufficient transcribers cannot be found, how can we do without them altogether? There are, however, certain features associated with the manual transcription of braille that have considerable potential for exploitation, but these features are 'masked' at the present time by the conditions and equipment transcribers have to work with - in many cases essentially the same since the beginning of the century.
The potential of manual transcription: equipment design The keyboards on mechanical braillewriters and stereotype machines are chord keyboards. They consist, basically, of six character keys, each one corresponding to one dot of the braille cell, and a space bar. By pressing combinations of these keys simultaneously, all 63 braille characters can be produced. A recent review (Seibel, 1972) of data entry devices and procedures, which included a section on chord keyboards, concluded that "the potential of chord keyboard data entry is very high. Indications are that entry rates of 150% of standard typing are relatively easy to achieve. It is recommended that chord keyboard systems be explored more fully for data entry purposes . . . . " The present equipment available to transcribers does-not begin to exploit the potential high-speeds of chord keyboards. In common use in England, for example, especially by book transcribers, is the Stainsby machine (see Fig. 1) which can be fairly described as an 'ergonomist's nightmare'. It possesses the following features: • The keys require considerable effort to depress (2 to 3 times that required for an ordinary mechanical typewriter, assuming that the Stainsby is in good condition). • A long stroke movement, which has to be made in full and with pressure to obtain a satisfactory braille dot. • The hands must point inwards, towards each other, see Fig. 2), thus causing the elbows to be held up, and away from the body. An extremely tiring posture!
Current use of Braille transcribers
• The 'keyboard/embossing unit' moves, from right to left, along a rack, after each depression of the keys. The rack
Despite the innovations in computerised braille production, manual transcription is still in widespread use. In a survey of seven European countries*, three -
* Conducted by Hampshire while on a Winston Churchill Travelling Fellowship in June 1975.
160
Applied Ergonomics September 1977
Charocter keys
Releoseclip for 'corrioge return'
bar
ordinary briefcase, whereas a Perkins is more akin to carrying a rather bulky portable typewriter. A further unfortunate anomaly between these two machines is that the key arrangements are different. On the Stainsby the 3rd, 2nd, and index f'mgers of the left hand are used for the keys corresponding to the braille dots 1, 2, and 3 respectively. On the Perkins, the same f'mgers are used for dots 3, 2 and 1, respectively. The corresponding reversal exists for the right hand also. In a project to design a new braille production system for the National Library for the Blind in Manchester undertaken by the authors (Whiston, 1975), an improved braille keyboard was built which wrote onto punched paper tape. This tape could then be used to produce braille copy from an automated embossing device. The keyboard unit is illustrated in Fig. 3.
Fig. 1
The Stainsby braille writer
and keyboard/embossing unit are moved down one position on the base plate after each line has been completed. • The keys are small and smooth, thus it is easy for the fingers to slide off them while using the machine. Given, furthermore, the position of the arms, when this happens there is little that the operator can do to stop his hand falling painfully onto the upward pointing serrations of the ratchet mechanism along which the keyboard moves.
Although this keyboard has not yet been thoroughly evaluated because of unreliability in the output unit, initial comments by users, both blind and sighted, were extremely favourable. However, the detailed design of this keyboard may not be optimum as manufacturing constraints played a significant part in its design. Nevertheless, it was clear that the operators found it considerably superior to using either the Stainsby or Perkins, which suggests that there is considerable need for further work in this area. One aspect which is particularly deserving of some investigation and effort is the development of a well designed braillewriter which is genuinely portable (in an ordinary briefcase), capable of writing on both sides of the paper, and reasonably silent. Today, apart from the above braillewriters, the only
• The space key is located to the right of the right-hand set of keys. Thus, to press this key, the thumb of the right hand must be curled under the fingers of the right hand in order to reach it. An alternative technique is to take the fingers of the right hand off the keys, and move them to the space bar, then back again to the character keys. • The Stainsby is a downward writer. This is to say that the 'keyboard/embossing unit' moves from right to left embossing the braille downwards. This means that, in order to check what has been written, the paper must be removed from the base plate and turned over. This is in contrast to upward writers (eg, the Perkins, see below) which allows the braille written to be checked immediately by touch or sight. This machine has been in use since about 1905! Just under a decade ago the Americans produced a new mechanical braille-writer - the Perkins - which is also in fairly widespread use in England and all over the world. However, the Stainsby has two crucial features which will ensure its continued use. These are: • The Stainsby can produce interpoint braille, ie, braille that is written on both sides of the paper such that the dots of the cells on one side are written between the dots of the opposite side. This allows, obviously, much more braille to be written on each sheet of paper, which, given the bulk of braille books, is an important feature. The Perkins only writes on one side of the paper. • The Stainsby is more portable than the Perkins. The rack and keyboard/embossing unit are separate from the base plate on which the paper is fixed. As this base plate can be folded, a Stainsby can be fitted fairly easily into an
Fig. 2
Stainsby braille writer showing operating position
Applied Ergonomics September1977
161
not influenced by the substitution of short forms. This crucial result suggests the contention that the substitution process can be carried on while typing without slowing the keystroke rate." Thus, for the fully srmlea braille transcriber, keying speed should be increased in proportion to the decrease in the number of characters used by contracted braille compared to print - about 30% for contracted English braille. Unfortunately, the degree of complexity of the braille code (see above) makes it a rather long and difficult task to reach a stage of proficiency where encoding does not take up an appreciable amount of the keying time. In theory, there is considerable room for improvement in the braille code. In the most recent statistical analysis of the efficiency of braille contractions (Kederis et al, 1965) it was found that only 76 out of the 255 symbols that are represented by one- or two-cell braille characters occurred over 1000 times. (This was out of a word population of 291 000, in which the most frequent character - 'E' occurred 61 882 times). Of the braille contractions included within these 76 characters (22% of all contractions), they saved 75% of the total number of character spaces saved by all the contractions.
Fig. 3
Keyboard unit of the braille production system builtfor the National Library for the Blind, Manchester
means for writingbraiUe (and it is in very widespread use) is the so-called 'slate and stylus'. This is a type of 'mask' that can be fitted over a piece of paper within which are 'windows' to guide the writer where to emboss the braille cells. The embossing is carried out using a blunt stylus to press out each dot of the cell individually. Although this equipment is extremely portable and writing speeds achieved are perhaps faster than one might expect (especially in view of the fact that the braille characters have to be written back to front so that they are the correct way round when the paper is turned over), it really ought to be possible to devise something better.
The potRntial of manual transcription: encoded input Encoding the input offers considerable potential for speeding up transcription processes. The most well known example of this is, perhaps, the Stenotyping system which is used for recording the proceedings of courts of law. The 'good' Stenotypist can enter 200 words per minute (wpm), with claims for upper rates exceeding 300 wpm. These can be compared with a 'good' typist who can enter something under 100 wpm (Seibel, 1964). The Stenotype keyboard is also of the chord type, so it is not certain how much of these increased rates is due to encoding and how much to using a chord keyboard as opposed to a single stroke per character keyboard. However, in one study examining the effects of redundancy-reducing codes utilizing single character per stroke keyboards (Schoonard and Boies, 1975) it was found that "Keying rate, in terms of characters per unit time, was
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Many proposals have been made for changing the braille code, the latest by Deuce & Tobin (1976), but these always meet with considerable resistance from users of braille, who tend to be extremely conservative when any new code changes are suggested. In view of this situation, a more immediately rewarding research direction might be in endeavouring to improve the rate of learning the braille code by investigating both the teaching and learning processes which occur today. Conclusion Although considerable attention has been paid to increasing braille provision by the development of technology, this attention has been focussed to a large extent on 'high technology'. As a result, manual transcription techniques and equipment have remained almost unchanged since the beginning of the century. Studies of keyboard equipment and use suggest that the manual transcription of braille has two important advantages over normal print transcription. Firstly, it utilizes a chord keyboard, and secondly, because the material is encoded by the transcriber, the number of keystrokes is reduced, and this should be without any loss of speed of keyboard operation if the transcriber is proficient with the code system. In view of these features, and a pressing need for the type of material, the production of which is better suited to manual transcription than to computerised translation, there is considerable need and scope for developing new equipment and techniques that will exploit the potential of manual transcription of braille rather better than present facilities allow.
References Anon 1975 AppliedErgonomics, 6. 4 , 2 3 7 - 2 3 8 . 1 5 0 Years of Braille.
Douce, J.L., and Tobin, M.J. 1976 Braille Automation Newsletter. February, 5-8. Discussion Paper on the Desirability of a Joint Project on the Braille Code, Extending the Use of Braille, and the Improvement of Reading Skills. Gray, P.G., and Todd, J.E. 1968 Mobility and Reading Habits of the Blind. Government Social Survey (SS386). HMSO: London. Kederis, C.J., Siems, J.R., and Haynes, R.L. 1965 The Education of the Blind. December. A Frequency Count of the Symbology of English Braille, Grade 2, American Usage. National Uniform Type Committee 1971 Restatement of the Standard English Braille System. RNIB; London.
Sehoonard, J.W., and Boies, S.J. 1975 Human Factors. 17, 2, 203-214. Short-Type: A Behavioural Analysis of Typing and Text Entry. Seibel, R. 1964 Human Factors, 6, 189-192. Data Entry Through Chord, Parallel Entry Devices. Seibel, R. 1972 Dafa Entry Devices and Procedures. In: H.P. Van Cott & R.G. Kincade (Eds) Human Engineering Guide to Equipment Design. Washington, DC. US Government Printing Office. 311-344. Whiston, T.G. 1975 Automatic Transcription of Braille. In: Proceedings of The Louis Braille British Conference on Research into Reading and Listening by the Visually Handicapped. Southern Regional Association for the Blind. Conference Report No 66.
CALL FOR PAPERS THE ERGONOMICS SOCIETY ANNUAL CONFERENCE 4 - 7 April, 1978 at the Cranfield Institute of Technology, Bedfordshire, England.
Papers are invited on all aspects of Ergonomics. Please send abstracts (300 words) as soon as possible to the Hon. Meetings Secretary, I A R Galer, Dept. of Human Sciences, University of Technology, Loughborough, Leics, U.K.
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