5
Research and Development Needs and Future Directions

Considerable research work is underway on topics such as causes, degrees, and types of visual impairment; responses to tactile and visual stimuli; and devices to assist visually disabled people. These research and development programs have contributed significantly to an understanding of the needs of visually disabled people for participating fully in fundamental activities of life. Many of these research programs have resulted in approaches for meeting those needs. Although some of the understanding revealed by this work is applicable to the design of banknotes for visually disabled people, little of the technical work has specifically addressed the issue of banknote design and implementation. Essentially no research specifically addresses features that will make it possible for all visually disabled individuals to denominate U.S. banknotes independently and confidentially.

The research required covers three areas. The first is psychophysical, directed toward determination of the significant dimensions and gradation of steps that will permit reliable human discrimination of the features. The second level of research is practical materials science, which is directed toward the materials and processes that will yield durable, wear-resistant, survivable, and environmentally acceptable materials for printing features on, or for adding relief to, banknotes. The final area of research is applied science and engineering, which should have the intent of devising methods for economically and reliably imprinting the required features at a scale commensurate with the production of durable banknote features.

Two types of needs and directions require technical work. In the short term, there are features that are not technically difficult to incorporate, but optimization of these features is needed. The nature of the near-term studies will tend to be empirical and psychophysical. In the intermediate term, research is required to identify the thresholds and optimum application of low-relief features for tactile sensing. The research and development needs and directions for features that might be incorporated in the long term will be considerably more fundamental and require identification of appropriate physical characteristics of new features. The long-term research will, in many cases, be dependent on the potential applicability of developments in electronics, photonics, materials, and nanotechnology.

Empirical/Psychophysical Technical Needs

As indicated in Chapter 4, the candidate features fall into a few categories. The technical information needed for features in each category is specified without detailed descriptions of



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--> 5 Research and Development Needs and Future Directions Considerable research work is underway on topics such as causes, degrees, and types of visual impairment; responses to tactile and visual stimuli; and devices to assist visually disabled people. These research and development programs have contributed significantly to an understanding of the needs of visually disabled people for participating fully in fundamental activities of life. Many of these research programs have resulted in approaches for meeting those needs. Although some of the understanding revealed by this work is applicable to the design of banknotes for visually disabled people, little of the technical work has specifically addressed the issue of banknote design and implementation. Essentially no research specifically addresses features that will make it possible for all visually disabled individuals to denominate U.S. banknotes independently and confidentially. The research required covers three areas. The first is psychophysical, directed toward determination of the significant dimensions and gradation of steps that will permit reliable human discrimination of the features. The second level of research is practical materials science, which is directed toward the materials and processes that will yield durable, wear-resistant, survivable, and environmentally acceptable materials for printing features on, or for adding relief to, banknotes. The final area of research is applied science and engineering, which should have the intent of devising methods for economically and reliably imprinting the required features at a scale commensurate with the production of durable banknote features. Two types of needs and directions require technical work. In the short term, there are features that are not technically difficult to incorporate, but optimization of these features is needed. The nature of the near-term studies will tend to be empirical and psychophysical. In the intermediate term, research is required to identify the thresholds and optimum application of low-relief features for tactile sensing. The research and development needs and directions for features that might be incorporated in the long term will be considerably more fundamental and require identification of appropriate physical characteristics of new features. The long-term research will, in many cases, be dependent on the potential applicability of developments in electronics, photonics, materials, and nanotechnology. Empirical/Psychophysical Technical Needs As indicated in Chapter 4, the candidate features fall into a few categories. The technical information needed for features in each category is specified without detailed descriptions of

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--> research procedures. An organization undertaking to make the recommended measurements should be familiar with problems associated with visual impairment and proficient in performing the suggested determinations. Visual/Tactile Features Variable Dimensions Most countries denominate banknotes by size along with other indicators. The size differences are generally in both length and width. The committee recommends thorough psychophysical studies to optimize the combination of length and height to permit reliable absolute judgment by banknote size. If a change in dimensions were to be made in U.S. banknotes, such knowledge would be helpful. Research in this area should be carried out with the goal of determining the optimum strategy for implementing the size variations recommended in Chapter 4. In some instances, templates are supplied to ensure that blind people will be able to denominate banknotes in accordance with size differences. In countries where templates have been supplied, it has been observed that after a short time, people who are blind learn to recognize denominations utilizing their sense of touch and no longer use the templates. On the other hand, if templates were built into wallets or other types of billfolds, it is probable that they would be used much more extensively. Such an arrangement would be of great help to those whose sense of touch has been impaired later in life, such as individuals with advanced cases of diabetes. Holes A practical concern is the effect of hole shape, size, number, and spacing on durability and wear. Empirical tests that address such questions are very much in order. It is important to determine the optimum hole size for easy identification and for rigidity with wear. Given an optimum hole size, the number and locations that are required to ensure accurate denomination and orientation would need to be determined. The effectiveness of the combination of a single hole for orientation or denomination with banknote dimensional changes for denomination should be assessed in terms of durability, wear, reliability, and aesthetics. The wear characteristics of suitable holes would need to be determined. Materials and processes appropriate for edging and forming such holes need to be identified. The treatment of the edges of such holes to promote long-term durability is an area that requires more research. Some research is also needed into the willingness of the public to accept banknotes that contains marks generally interpreted as invalidating.

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--> Visual-Only There is substantial literature on visual processes and perception under a range of conditions. The committee found that most of the data are not directly relevant to the specific case of banknote applications. Identification of the smallest useful set of features should be made, and optimum use of these features identified. One or more colors could easily be combined with a visual/tactile feature or with a feature that is tactile only. Early research into these features should establish a basis for contrast, size of features, and selection of appropriate colors that can be used to enhance discrimination by visually disabled persons. The existence of an extensive visual science literature indicates that identification of requisite characteristics of these features would require development, not research. Numerals Though there is a substantial body of research on size (width and height) of characters; optimum optical contrast as a function of illumination, intensity, and wavelength; whether the characters should be black on white or the converse; optimum location; and whether characters should be in more than one location, there has been little research directed toward banknote denomination and recognition. Application of the existing body of research to the optimum type of numerals and ratio of numeral-to-background areas for banknote denomination requires some development, and continued research into more long-term ideas, such as the effectiveness of fluorescence or scintillation in the areas occupied by the numerals, is recommended. Color The selection of effective colors for banknote denomination, as well as the degree of saturation required to ensure easy and accurate recognition by visually disabled individuals, is an area about which much is still unknown. To maximize color discrimination over as wide a range of lighting conditions as possible, development is needed on the application of color theory to the selection of hues for banknote denomination. Included in this effort should be optimum colored area, size, location, number, shape, and color combinations. It is also possible to incorporate phosphorescent or fluorescent material that would glow if illuminated by ultraviolet light or in some cases by ordinary white light. Such an attribute may be extremely useful under poor illumination conditions for normally sighted individuals as well. One or more counterfeit deterrents could also be incorporated in colored areas. Optically variable inks are being considered in the new banknote design. Research is needed to determine if this feature would be applicable to denomination coding of banknotes or if it is too subtle for people with low vision.

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--> Tactile-Only If tactile-only features were to be incorporated into banknotes, certain information about the nature of such features is essential in order to maximize the probability that they will be useful over the life of the banknote. There is some question about whether the raised areas should be bumps; characters; lines; or some other shape, such as a doughnut. Information on minimum height to ensure accurate, reliable recognition is essential, as is the effect of age and wear as a function of height. The optimum presentation of a tactile mark needs to be approached in terms of banknote manufacturing, as well as the psychophysical or human factors area. Most research in tactile character reading has concentrated on braille, where the symbols are approximately 400 µm higher than the background surface. In contrast, intaglio printing can produce features approximately 60-70 µm high. Short-term investigations into ability to read such low-relief features should establish minimum detectable feature heights and dimensions. The nature of the tactile feature, that is, its shape; the number of individual elements (such as dots or lines); and the spacing of any individual elements will have an effect on the minimum detectable height and need to be considered in concert with the height criteria. Knowing minimum detectable feature heights and dimensions would allow researchers to determine the acceptable amount of wear that a tactile feature can experience before the feature is no longer useful. To ensure that these tactile marks remain recognizable over the lifetime of the banknote, more-durable marks than are currently available will be required. More investigation into methods of making the tactile marks durable is necessary before implementation can be recommended. Another problem that would require research is the effect of raised or tactile features on the ability to manufacture, stack, and sort banknotes at high speed and to determine what sorts of tactile features would minimize these problems. There has been extensive research into the most effective way to present tactile denominators, especially in the Netherlands. The committee recommends that the Treasury Department and the Federal Reserve stay apprised of the work going on overseas and of experiences with circulation of banknotes with various types of tactile marks. As a result of the technical work discussed, raised-relief features could be developed and tested against sound technical guidelines. Feature Combinations Research is recommended to study various combinations of features to determine an optimum set to improve ease of denomination or to add authentication or orientation information. The extent of success of visually disabled individuals in using these combinations should be quantified, and the research carried out in this area should be directed toward the identification of a figure of merit for combinations of features.

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--> Substrate Materials For several of the features discussed to be more effective and more durable, research is needed on the currency base paper. The fibrous composition and sizing of this substrate is specified by the government and has changed little through the years. Research that could lead to greater durability and thus longer life even in current banknotes would be beneficial. It would be appropriate to consider other, new fiber furnishes (containing some portion of synthetic fibers, for example) or layered composite structures. Some synthetic (plastic) papers may also be suitable as currency base paper. A composite substrate that could resist abrasion would be ideal for tactile features to aid visually disabled as well as normally sighted people. Tactile features might also be more effective with the use of a smoother substrate, from which they would stand out more easily. Current paper-making practices result in papers that delaminate easily, usually because the hydrodynamic forces during paper making cause the fibers to be arranged in the plane of the sheet with very little out-of-plane orientation. A substrate that would resist delamination, perhaps a composite in which the fibers had some out-of-plane orientation or contained tough synthetic fibers, would be ideal for banknote features involving holes, clipped comers, or modified edges. Research directed to improve current U.S. banknote base paper could have significant impact on note durability and on the ability to incorporate certain counterfeiting deterrents, as well as robust aids to help visually disabled people. Devices The committee agrees that a desirable approach would be to permit virtually all visually disabled individuals, together with normally sighted persons, to denominate banknotes without the aid of devices. It is conceivable, however, that under certain circumstances very simple, inexpensive, unobtrusive, and accurate devices could be of assistance under dim lighting conditions—not only to visually disabled people but also to normally sighted individuals. Since a device is the only method of authentication of banknotes by a blind individual, it is appropriate for short-term technical work to be undertaken that concerns itself with the potential advantages and utility of very simple devices that could be available immediately. Together with this should be a longer-term, highly focused research and development program designed to derive much more sophisticated devices. Adaptation of Current Devices Fixed-placement devices are currently in use in vending machines, ATMs, and retail establishments (e.g., ultraviolet lamps to detect the presence of optical brighteners). Information should be provided on overt features to enable device designers to make devices more portable, smaller, faster, and more reliable, both for use by visually disabled individuals and for those who currently use fixed-placement devices.

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--> Some types of very simple, inexpensive, devices that are currently available and that could prove useful for banknote denomination in various settings are a small flashlight on a key chain, which could be made wavelength-selective utilizing filters; a small magnifying glass, perhaps equipped with a light source; plastic templates that could be used to denominate different-sized banknotes (were there a hole in the currency, this template could also be used for front-to-back differentiation and rotational orientation); a light source such as either light-emitting diodes (LEDs) or lasers to emit a single wavelength or a broad spectrum of light; and finally, a very simple magnetometer that senses a predetermined magnetic pattern in the banknote and converts the information to aural, visual, or tactile information. In all cases, the physical processes are well known, but research and development into miniaturization and reliability is required. It is likely that such development will be market driven. Technologically Advanced Devices Very advanced devices could not only recognize and denominate but also authenticate banknotes. They must be inexpensive, reliable, easy to use, inconspicuous, and quick, and they must give acceptable rates of false positive and false negative readings. Ideally, such a device would be built into a wallet or other equally ordinary item and provide a visual, aural, or tactile response. Devices of this kind would probably require incorporation of active or passive material into bank notes. The possibilities are myriad. However, the performance and cost requirements are extraordinarily stringent. It is highly probable that the basic technology on which such devices will be predicated will come from significant advances in areas like photonics, molecular electronics, microwave and radar emission and sensing, microelectronics, nanotechnology, and materials. Research in these areas is increasingly underway in university, government, and industrial research and development laboratories. For example, low-cost radar technology developed at the Lawrence Livermore National Laboratories has been adapted for use in inexpensive tools that permit location of wires, pipes, and studs in walls and underground (FLC, 1994). Another possibility could be based on an LED array and a photosensor. Such a device could be very small and, with continued materials and manufacturing advances, quite inexpensive. In addition to staying abreast of the research and development discussed, it is also imperative for currency designers and manufacturers to maintain contact with the research and development centers concerned with aiding visually disabled people. It is important that advances in the various potentially relevant sciences and engineering disciplines be monitored and their relevance to potential Treasury Department or BEP interests or needs recognized. The committee supports the approach suggested in the National Research Council report on anticounterfeiting measures that the BEP or other appropriate body sponsor annual or semi-annual technical workshops (NRC, 1993), in this case to encourage development of the field of features usable by visually disabled people.

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--> Smart Money The long-range possibility that features can be developed that will permit individuals with any degree of visual impairment to both denominate and authenticate banknotes cannot be ignored. Such currency might respond to touch and transmit to the individual aural, visual, or tactile information that would permit easy, rapid denomination and authentication. The principal barrier would probably not be technology but the development of durable materials and the cost of manufacturing. The components might be divided into two parts, with the very inexpensive portion incorporated in the note and the more expensive portion built into a very simple, easy-to-use aid such as a wallet or a card or glove. These types of designs may prove to be too expensive for inclusion in lower denominations but could be used effectively in larger denomination banknotes. Conclusions and Recommendations Development of features building on the extensive literature on visual and tactile processes and perception is warranted for near-term banknote feature additions. Highly directed, psychophysical/empirical technical work should be undertaken as a high priority effort that addresses questions regarding optimum dimensions, optical contrast, location, colors, physical size, etc., for making recognition and denomination of U.S. banknotes easy, convenient, and inconspicuous for visually disabled individuals. Similar to the work suggested for individual banknote features, technical work should also be performed to identify combinations of features that enhance denomination and orientation. Near- or mid-term research is required to define the threshold and accuracy for reading the types of low-relief tactical features that are likely to be applicable to banknotes. Long-term research into advanced features, possibly leading to smart money, should be initiated as possible directions become evident from technology development. Advances in microelectronics, nanotechnology, molecular electronics, materials, photonics, and magnetics should not only be followed but also encouraged by supporting technical work that is focused on deriving very sophisticated but inexpensive, reliable, accurate, inconspicuous devices to assist visually disabled people in recognizing, denominating, and perhaps authenticating U.S. banknotes. Technical work underway by organizations and institutions concerned with the problems of people who are visually disabled and with solutions to those problems should also be followed. Very often, these organizations themselves maintain contact with the technological areas identified and are in a position to adapt them for their own purposes, that is, to ultimately benefit visually disabled individuals.

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--> References FLC. 1994. FLC Newslink. June. NRC (National Research Council). 1993. Counterfeit Deterrent Features for the Next-Generation Currency Design. National Materials Advisory Board, NRC. Washington, D.C.: National Academy Press.