Emitting LED Block at Crosswalk Entrance for Visually Impaired Persons

Available online at www.sciencedirect.com

ScienceDirect Procedia Manufacturing 3 (2015) 3147 – 3151

6th International Conference on Applied Human Factors and Ergonomics (AHFE 2015) and the Affiliated Conferences, AHFE 2015

Emitting LED block at crosswalk entrance for visually impaired persons Norihiro Ikedab, Kazuya Takahashic, Tomoyuki Inagakid, Katsuya Satoa, Sin-Ichi Itoa, Motohiro Seiyamaa, Shoichiro Fujisawaa, * a

Tokushima University, 2-1 Minami-josanjima, Tokushima 770-8506, Japan b KICTEC Inc., 150 Umegaoka, Agui, Chita, Aichi, 470-2295, Japan c General Support Center for the Visually Handicapped , 2-37-10 Kamiogi, Suginami, Tokyo 167-0043, Japan d Nihon University, 7-24-1 Narashinodai, Funabashi, Chiba 274-8501, Japan

Abstract Visually impaired persons require tactile walking surface indicators (TWSIs) for independent walking. However, if these blocks are installed following guidelines for constructing TWSIs, it’s unkind to users. Therefore, we propose LED blocks installed at crosswalk entrances for blind and visually impaired persons. These blocks can be detected through the soles of shoes and through use of residual vision. This study conducted an experiment with amblyopic examinees in which we evaluate the visibility of the LED blocks. © byby Elsevier B.V. This is an open access article under the CC BY-NC-ND license © 2015 2015The TheAuthors. Authors.Published Published Elsevier B.V. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of AHFE Conference. Peer-review under responsibility of AHFE Conference Keywords: TWSIs; Visually impaired person; Assistive devices; LED block; Crosswalk

1. Introduction According to WHO, about 80% of visually impaired persons have low visual capacity (LV). LVs’ safe independent mobility will be improved if Tactile Walking Surface Indicators (TWSIs) are installed. Guidelines for installing attention TWSIs, a kind of TWSI, for nighttime use are not well established. Therefore, crossing

* Shoichiro Fujisawa. Tel.: +81-88-656-7537; fax: +81-88-656-2169. E-mail address: [email protected]

2351-9789 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of AHFE Conference doi:10.1016/j.promfg.2015.07.863

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(a)

(b)

Fig. 1. (a) Laboratory and (b) illumination system.

crosswalks is one of the most dangerous situations for visually impaired persons. Experiments have also been conducted on many electronic travel aids such as Talking Signs [1]-[7]. However, no research has examined the interrelation of the TWSIs and the LED blocks at intersections. We propose LED blocks [8] installed at crosswalk entrances for blind and visually impaired persons. These LED blocks can be detected through the soles of shoes and through use of residual vision. A visually impaired person walking at nighttime can cross the crosswalk by discovering the LED block set up in the opposite side of the crosswalk. 2. Experiment method 2.1. Experiment environment The illuminance of the pavement should be 10 lx or 20 lx according to domestic guidelines in Japan. Tokushima University provides a laboratory where various experiments can be conducted in a low-illuminance environment. Figure 1 depicts the laboratory and the illumination system. We used the laboratory of the Graduate school of Tokushima University and its experiment system. A lighting system on the ceiling with dimming control that can vary illuminance by lux are installed in the laboratory. Daylight-color fluorescent lamps (National FLR40S EX-D/M) were used as the illuminating light sources during the experiment. We conducted an experiment in a room with a dimmer and a model of a crosswalk illuminated at 10 lx and 20 lx to simulate morning and night (mesopic). This laboratory can support experiments that simulate subjects crossing cross walks.

(a)

(b)

Fig. 2. LED block. (a) Spacing and dimensions; (b) LED block installed at crosswalk entrance.

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(a)

(b) Fig. 3. Emitting LED block with (a) one row and (b) two rows.

Fig. 4. Simulation model of crosswalk. Table 1. Luminance of four combinations. An example of a column heading

One row (cd/m2)

Two rows(cd/m2)

Maximum dissipation

106

56

Half electric power

56

30

Table 2. Subject’s grade of disability. Grade

1

2

3

4

5

6

Count

11

8

1

0

0

0

2.2. Experiment method The experiment measured the range of visibility for illuminance of 10 lx and 20 lx. Figure 4 shows the installation of TWSLs and the LED block. The attention TWSIs and the guiding TWSIs are installed at the crosswalk exit of the opposite bank (Fig. 1). The subject stopped where the luminescence block could be checked visually at a distance of 10 m. The experiment combines two environmental illuminances (10 lx and 20 lx) and four emitting patterns. Eight patterns were randomly selected for each subject. Each experiment was conducted ten times.

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Fig. 5. Relation between distance to crosswalk exit and experiment environment.

Each subject performed 80 trials. To do the experiment management, a white cane was assumed to be no use. The experimenter measured the distance to the LED block. Table 2 presents the subject's degree of disability. Twenty visually impaired subjects (ten males and ten females; mean age 63.5, SD 6.3) participated in the experiments. This experiment targeted subjects regarded as having difficulty walking at nighttime because of nyctalopia etc. Therefore, primarily persons with first and second level visual impairments participated. 3. Experiment results Figure 5 presents the mean values of data obtained from the experiment. The vertical axis represents the visual checking distance, and the horizontal axis represents the experiment environment. The method of expressing the experiment environment is [number of emitting LEDs –cd/m2 (luminance of LED)]. There were 200 samples. The visual checking distance for 20 lx was confirmed to exceed that of 10 lx in all luminescence patterns. The visual checking distance was increased in the order of one row of 106 cd/m2 , two rows of 56 cd/m2, one row of 56 cd/m2, and two rows of 30 cd/m2.. The indoor visual checking distances were the same for illuminances of 10 lx and 20 lx. Next, the Tukey’s test was used at p= 0.05 to compare the obtained data. Table 3 presents the test results. The result for 10 lx indoor illuminance is presented in Table 3-(a), and the result for 20 lx illuminance is presented in Table 3(b). In the 10 lx environment, a significant difference was confirmed to one row of 56 cd/m2 and two rows of 30 cd/m2 for one row of 106 cd/m2. Similarly, a significant difference was also confirmed to two rows of 56 cd/m2 and two rows of 30 cd/m2. However, no significant difference was confirmed for indoor illuminance of 20 lx. Table 3. Result of Tukey’s test. a)

Interior illuminance 10 lx 2

b)

Interior illuminance 20 lx

Number-cd/m

1 - 56

1 - 106

2 - 30

Number-cd/m2

1 - 56

1 - 106

2 - 30

2 - 56

20.9%

94.1%

4.0%

2 - 56

98.7%

99.9%

74.3%

2 - 30

99.8%

0.05%

2 - 30

99.6%

36.5%

1 - 106

0.60%

1 - 106

83.5%

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Fig. 6. Histogram and cumulative ratio of distance from LED block.

Figure 6 plots the histogram of 106 cd/m2 in luminance of the LED block of one row. The visibility of the LED block increased from about 5 m. A similar tendency was seen for other emitting patterns. The effectiveness of the LED block was demonstrated in the latter half of the crosswalk. 4. Conclusion The visibility at maximum dissipation exceeded half of the maximum dissipation though it was natural. For the same power consumption, one row was more visible than two rows. That is, for the same amount of electric power, the visibility is better when the brightness is higher. In this research, the visibility of the LED block was verified by the difference of the luminescence and the illuminance environment. This result clarified how to provide illumination for a visually impaired person. The finding of the method of presenting low vision person's illuminant was clarified from this result.

References [1] J. M.Loomis, R. G. Golledge, R. L. Klatzky: GPS-based navigation systems for the visually impaired. In W. Barfield & T. Caudell, (Eds.), Fundamentals of wearable computers and augmented reality. Mahwah, NJ: Lawrence Erlbaum Associates, 429-446, (2001). [2] Y. Ikeda, N. Mori: Research on ITS for pedestrians; Proceedings of Tranced 2001, , 106-112 (2001). [3] A. C. Kooijman, M. T. Uyar: Walking speed of visually impaired people with two talking electronic travel systems; Visual Impairment Research, Vol.2, No.2, 81-93, (2000). [4] L. Fanucci, R. Roncella, F. Iacopetti, M. Donati, A. Calabro, B. Leporini, C. Santoro: Improving Mobility of Pedestrian Visually-Impaired Users, ASSISTIVE TECHNOLOGY RESEARCH SERIES, Vol. 29, 595-603, (2011). [5] J. M. Loomis,J. M. Philbeck, P. Zahorik: Dissociation Between Location and Shape in Visual Space, Journal of Experimental Psychology, PP.1202-1212, Vol. 28, No. 5, 1202-1212, (2002). [6] J. M. Loomis, J. M. Kbapp: Visual perception of egocentric distance in real and virtual environments, In LO. J. Hettinger and M. W. Haas (Eds.), Virtual and Adaptive Environments, (2003), 21-46. [7] J. W. Kelly, J. M. Loomis, A. C. Beall: Judgments of steering without course information, Perception, No. 33, 443-454, (2004). [8] N. Ikeda, K. Takahashi, G. Yamamoto, Y. Kimura, S.Ito, K. Sato and S. Fujisawa, Verification of LED Blocks used at Crosswalk Entrances for Persons with Visually Impairment, Assistive Technology Research Series, Vol. 33, pp. 982-987, 2013