Electronic Travel Aids New Directions for Research (1986) / Chapter Skim
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5: Sensory Enhancement and Substitution
5: Sensory Enhancement and Substitution
Pages 53-66
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From page 53... ...
Use of these other modalities requires that a person pay more careful attention to the spatial stimuli present in the environment and the use of sensory aids, especially for information requiring high resolution. Although learning is necessary to use spatial information acquired through any sensory modality, there are special problems in the absence of visual information or with the use of sensory aids.
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From page 54... ...
THE VISUAL SYSTEM What are the visual requirements of mobility? We consider separately visual information gathered from immediate and more remote environments.
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From page 55... ...
Experimental psychologists could contribute to the understanding of mobility by defining the involvement of these cues in mobility tasks and by showing how their use is affected by various visual impairments. Vision of the remote environment may also be discussed in terms of more global abilities, such as the ability to follow a path from instructions, the ability to reverse a path traveled once, the ability to locate oneself with respect to objects, and the ability to achieve a memorial representation of the environment in which the travel task is performed.
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From page 56... ...
The use of Corning CPF color filters for mobility is an intriguing but not yet well-understood form of sensory enhancement. In these examples, some properties of patterns of visual stimulation are transformed, while other properties are invariant.
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From page 57... ...
The human auditory system is capable of detecting binaural time of arrival differences as short as 30 microseconds and binaural intensity differences in the single dB range. The pinna also has as effect on the localization of sound sources in space.
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From page 58... ...
This resolution appears to be based on neural activity transmitted via slow adapting (SA3 afferents and for complex patterns, like letters, it is not greatly different whether the spatial stimuli are applied to the finger in a stationary manner or the fingers are swept across the stimuli. It is also an interesting fact that the relationship between resolution and the primary afferents is the same in the skin and in the foveal region of the retina.
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From page 59... ...
However, Stereognosis is extremely important and lies at the heart of the success of the cane. Implications for Sensory Aids How might the somesthetic sense serve the purposes of a sensory aid?
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From page 60... ...
However, these skin areas might provide an effective portal for low-resolution information. EXI STING ENVIRONMENTAL SENSORS A variety of sensory aids for visually impaired people have been developed as technology has advanced, which are discussed in Chapter 6.
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From page 61... ...
One effect of using the Trisensor appears to be a reduction over previous devices in the magnitude of directional errors, and it is reasonable to attribute such an effect to an increase in angular resolving power brought about by the incorporation of a center channel. However, so far there has been no direct psychophysical comparison of the Trisensor and the Binaural Sensory Aid.
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From page 62... ...
The Somatosensory System If sensory aids are to take full advantage of the capacities of the somatosensory system, they must effectively engage the mechanisms responsible for tactile perception and stereognosis. Natural examples of tactile perception are Braille reading and texture perception.
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From page 63... ...
Closer interaction between engineers and psychologists with specialization in human factors engineering would facilitate this endeavor. A more thorough assessment of existing sensory aids is needed, but there are more fundamental issues that must be addressed.
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From page 64... ...
The effect of visual impairment on spatial learning also merits study. When the natural optical display from which visual observers acquire spatial information is transduced to create an acoustical display, extensive recoding takes place.
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From page 65... ...
Detrimental Effects of Mobility Aids The designer of a sensory substitution system should be mindful of the natural ability of the sensory system to be addressed and the interference that may be caused by substitute signals. For instance, the auditory system has useful ability to acquire spatial information from the natural acoustic display, and the benefits associated with the use of a sensory substitution system must be weighed against the costs incurred by compromising natural auditory ability.
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From page 66... ...
The possibility of being able to control modifications or organizational processes in order to enhance compensation in the advent of a sensory deficit presents a significant challenge to science and technology. RECOMMENDATION: Research should be encouraged on the use of animal models to study the effects of device use on sensory development and functioning and to assess the relative contributions of the various kinds of information provided by sensory aids to the development of spatial knowledge and spatial ability.
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