Accessible Maps for the Blind: Comparing 3D Printed Models with Tactile Graphics

[Wotipati]

Links

• Paper: https://dl.acm.org/citation.cfm?id=3173772

Authors

• Leona Holloway, Kim Marriott, Matthew Butler

Abstract

• Tactile maps are widely used in Orientation and Mobility (O&M) training for people with blindness and severe vision impairment. Commodity 3D printers now offer an alternative way to present accessible graphics, however it is unclear if 3D models offer advantages over tactile equivalents for 2D graphics such as maps. In a controlled study with 16 touch readers, we found that 3D models were preferred, enabled the use of more easily understood icons, facilitated better short term recall and allowed relative height of map elements to be more easily understood. Analysis of hand movements revealed the use of novel strategies for systematic scanning of the 3D model and gaining an overview of the map. Finally, we explored how 3D printed maps can be augmented with interactive audio labels, replacing less practical braille labels. Our findings suggest that 3D printed maps do indeed offer advantages for O&M training.

スライド出典: CHI勉強会2018 スライド作成者: 北海道大学 渡邉拓貴さん

[XiyueWang-Miraikan]

Approach

• Pilot study
  • A pilot study was conducted first to gather feedback on possible applications of 3D printing for accessibility.
    • A wide variety of 3D models-buildings, cityscapes, and maps were shown to 21 severely vision-impaired adults.
    • A clear preference for 3D models of street maps and floor maps over tactile maps was demonstrated.
  • A hand-on workshop was run at the Round Table Conference on print disability.
    • Twenty-five accessible format producers, teachers, and vision-impaired users were presented with tactile graphics and 3D printed models.
    • Comments suggested that the 3D maps were more engaging and allowed more intuitive representations of stairs, walls, and doorways.
• Main study: Comparing Tactile Maps & 3D Print
  • Hypotheses:
    • H1: 3D maps will be easier to understand than tactile maps due to easily recognized 3D iconic symbols.
    • H2: Relative height of objects in a 3D model will be more easily understood and offer a performance advantage.
    • H3: Using a 3D map, it’s easier for touch readers to construct a detailed mental model. (Better recall of features and layout)
  • Designed 2D tactile graphics and 3D maps (1 neighborhood, 2 train stations, 2 parks in each format) based on the same tactile graphic guidelines with several iterations.
  • A controlled study was run to validate the hypotheses.
• Touch reading strategies are analyzed
  • Participants placed their hands over both types of graphics to gain an overview. (More frequent in 3D)
  • Scanning during the exploratory phase is not inhibited by 3-dimensional elements.
  • 3D maps: More vertical movements. Using fingertips.
• A 3D campus map with audio labels is prototyped
  • Using a user-driven design methodology.
  • Three models with iterative refinements based on feedback from vision-impaired students.
• A guideline is proposed for the design of 3D printed maps, interactive audio labels, and 3D map reading training.

  Evaluation

• Participants: sixteen adult touch readers (Eleven of the participants had the experience with 3D printed models)
• Training phase
  • Get familiar with a tactual exploration of a 3D model with explicit instructions (E.g. “feel the sides of the buildings all the way to the base to find the doors”.)
• Test Phase
  • Pre-experiment: A verbal description giving contextual information
  • Experiment: Exploration by asking and confirmation -> Model removed, recall questions -> Model returned, route-finding questions. -> Four experience evaluation questions.
  • Post-experiment: Three final questions were asked to test longer-term recall.
• The total time is about 1 hour.

  Result

• 3D maps are more preferred.
• The use of 3D iconic symbols is more understandable.
• The 3D map holds a modest higher accuracy in route-finding.
• The 3D map may take a shorter time to explore due to content.
• In terms of the mental map, improved memory performance was supported for short-term recall but not for long-term recall.

  Limitation & Future Work

• Participants were touch readers with experience reading tactile graphics.
• A replication of the study with participants with recent vision loss is needed to determine whether similar benefits are found.

[XiyueWang-Miraikan]

Guidelines

Design of 3D printed maps and plans:

1. As with tactile graphics, additional explanations should accompany 3D models to provide a context in which to understand the model.
2. The 3D model must physically allow the reader’s fingers sufficient space to easily explore the salient features.
   • Adequate space must be allowed for fingers to explore all pathways including access under overhanging objects.
   • This may require widening of streets and laneways.
3. The height of buildings and walls should represent their relative height.
   • The vertical scale can differ from the horizontal scale.
   • Heights should be low enough for the fingers to easily reach the base.
4. Features like streets or paths that are intended to be traced by a finger can be easily understood and followed if an indented path wide enough to contain the fingertip is used
   • rather than the raised lines commonly used in tactile graphics.
5. Where possible, use iconic 3D symbols to represent stairways, buildings and other 3-dimensional landmarks.
6. Be careful to ensure that there are no sharp points on map elements
   • They could cause discomfort if
     • the touch reader moves their fingers over it quickly
     • places their hands on top of the map.

       When providing interactive audio labels:

7. Audio trigger points should not be intrusive or distort the appearance of the 3D map.
8. Triggering of auditory information should be the result of a definite action.
9. The use of different interaction gestures to convey levels of information allows users to build their understanding to the depth they wish.

   Insights into training touch readers to read 3D maps:

10. Instruction in techniques for reading 3D models is required, in the same manner that training is now given for reading tactile graphics.
11. Encouragement is needed to feel the sides and base of objects.
    • There is a tendency to touch only the tops of map elements, causing lower features to be missed.
12. A quick overview of 3D maps can be gained by placing both hands on top of the map.

[XiyueWang-Miraikan]