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Automation of the DTW Process

The aim of this study is to replace the one-on-one human facilitator in the feedback loop (Figure14 — adaptive learning) with an automated system — one based on a neural network pattern classifier. Further, our basic aim is no longer to produce text output from speech input, but rather images. Cast in terms of a pattern recognition problem, suddenly artificial neural networks become relevant again, whereas for conventional speech recognition they have been largely superseded by hidden Markov models.

A 2002 pilot study centered around the Macintosh-based proof-of-concept system shown in Figure 15. It comprised: (a) a voice input pre-processor (microphone, sound card, and noise filter), (b) a fast Fourier transform package (which converted sampled words to frequencies), and (c) an ANN pattern classifier (the output from which was the 1-of-n “best match” from the reference word look-up table). We hasten to add that this reference vocabulary was kept very small in this first instance.

Figure 15. Original Macintosh-based system (2002)

‘Talk-Write’

Figure 16. Apple Macintosh G4 screen dumps of Talk-Write software (top: user manual; bottom: input)

By the end of this 12-month inaugural study, whilst some success was forthcoming with each of these three sub-sections, the overall system performance was somewhat lacking.

A second system was developed the following year. A screen dump from the Apple Mac G4 screen is shown in Figure 16, from which we see integration of IBM ViaVoice®, as well as support for additional input devices — namely scanner, graphics tablet and mouse. These latter devices are needed in order to augment speech input. More specifically, users are able to input their own drawings (either pre-prepared or new, via the tablet or mouse), in order to complement their oral stories.

As a first approximation to speech recognition for literacy, images could simply be linked on a one-to-one basis with words in the inbuilt vocabulary look-up table — whether that be as part of the Macintosh OS/X™ inbuilt speech library, or third-party software packages such as Dragon NaturallySpeaking™ or IBM ViaVoice® (the latter is shown in Figure 16). Ultimately however, we are aiming to do this the other way around

— in other words, to produce image output from speech input, then link the former on a one-to-one basis to text. Over time the user begins to associate (internalize) these words and images as part of the DTW process.

Other system features critical to producing an automated DTW “engine” are:

1. storage of speech input in a form easily indexed and retrieved as needed, and 2. synchronised playback of keywords/phrases in the speaker’s own voice rather

than in the unrealistic styles used in commercial speech synthesis packages.

Up to the present time, an unrealistically small reference vocabulary has been used;

obviously this would need to be expanded significantly before a production version is released into the marketplace. More to the point, we have yet to determine just what constitutes a “minimum yet sufficient”-sized vocabulary to enable users to tell their stories (and no doubt this will vary considerably from user to user).

CONCLUSION

This work-in-progress has thrown up numerous exciting possibilities for future investigation. Apart from the system issues outlined above, there is much experimenta-tion that could be performed to determine optimum pattern recogniexperimenta-tion configuraexperimenta-tions (to date, only simple, naïve multi-layer perceptron/back-propagation neural networks have been used). Likewise, we have yet to benchmark ANNs against alternative pattern classifier approaches.

The future possibilities and applications of draw-talk-write are limited only by our fears and lack of perceived safety. For example, “literary dramaturgy” has recently enabled people to consider and experiment public writing processes with literacy-inefficient people. DTW provides rich potential for minorities to voice, witness, and be heard by audiences who demand text and belittle those that have not mastered it.

What we need to assist us in our endeavours is technology that can record voice into text, synchronise it with playback in the voice of the narrator and the production of images, in other words, an intelligent system which incorporates word recognition, but which is configured in a manner that enables computer illiterate people to utilise the

system. Thus the computer system needs to respond to the user, rather than constrain people because they cannot meet the demands or limitations of the machine.

Lastly, successful automation of DTW on a computer platform would have far-reaching consequences beyond the specific (text-illiterate) section of the population of interest in the present study. Indeed, any community possessing a strong oral (story-telling) tradition could stand to benefit from this technology. Moreover, since the system output is images rather than text, it would have universal appeal.

ACKNOWLEDGMENTS

Financial support for this project from the Apple University Development Fund — AUDF — is gratefully acknowledged. The contributions of the following colleagues are likewise much appreciated: Kim Draisma, Ernie Blackmore, Marion Worthy, David Welsh, Frances Laneyrie, “the Dancer” and “the Prisoner” (fellow DTW travellers); Brian Pinch, Sunil Hargunani, Rishit Lalseta, Benjamin Nicholson, Riaz Hasan, Brij Rathore, and Phillip Dawson (software developers); and Professor Michael Wagner (proofreading and comments).

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ENDNOTES

1 Two well known examples of ANNs learning unexpected input-output associations are (a) sunny versus cloudy days instead of images of forests with and without Army tanks, and (b) photographs of ‘males’ versus ‘females’ being classified not on the basis of gender, but rather on the amount of white space between the tops of their heads and the top of the photograph [ref. The Dream Machine, Episode#4, BBC 1991].

2 Technical And Further Education — technical/vocational post-secondary school colleges.

APPENDIX: AUTOMATIC SPEECH