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Page 433 Chen et al. Intell Robot 2023;3:420-35 https://dx.doi.org/10.20517/ir.2023.24

Table 4. Walking experiment with a single object
Direction Distance
More than 2 m Number of successes 20 17
Success rate 100% 85%
Less than 2 m Number of successes 20 19
Success rate 100% 95%

Table 5. Walking experiment with multiple objects
More than 2 m Less than 2 m
Number of successes 14 16
Success rate 70% 80%

user should move to the left; then, the user immediately moved forward and to the left. When the distance
to the obstacle was still more than two meters, the motors vibrated relatively slowly, which could alert the
user to prepare for a directional movement. However, if a mistake was made in the recognition part, the
wrong vibration pattern was presented, causing the user to fail to pass by the obstacle.

As a future solution, if the performance of Raspberry Pi can be updated to be compatible with a camera with
a higher resolution, YOLO alone will be able to detect faces at greater distances, which is expected to
increase the overall accuracy and success rate. With more computing power, the matching algorithm for the
detection of multiple objects would be faster and smoother.

5. CONCLUSIONS
Focusing on providing mobility assistance to visually impaired people, this study developed a wearable
system equipped with a distance measurement function that included its tactile presentation via a
corresponding vibration pattern.

Real-time object detection, which is a part of the system, used YOLO V3 models, stereo cameras, matching
methods, and skin color detection to achieve obstacle detection. For the tactile display, by employing the
vibration characteristics of SMA actuators and also by embedding them in the tactile glove, the signals
provided due to real-time object detection were properly converted into vibration patterns to present
proper tactile movements for avoiding objects.

Due to limitations in the computing power of Raspberry Pi, however, the detection accuracy and execution
speed have yet to reach a satisfactory level. Thus, we are planning to improve the performance accuracy and
processing speed through hardware updates in the future.

DECLARATIONS
Authors' contributions
Conceptualization, investigation, validation: Chen Y, Shen J, Sawada H
Data curation, formal analysi,methodologys, visualization: Chen Y, Sawada H