Diversification of a novel tap operation interface forpeople with visual impairment
Kyo Kato

Hayato Maki

Kenji Funahashi

Nagoya Institute of Technology, Japank.kato.789@stn.nitech.ac.jp

Nagoya Institute of Technology, Japanh.maki.563@nitech.jp

Nagoya Institute of Technology, Japankenji@nitech.ac.jp

Index Terms—capacitive touch screen, tap operation, nonvisual state

I. I NTRODUCTION
PCs and cell phones have physical buttons such as a
keyboard and call buttons, but a touch screen device usually
does not. Since there are no tactile marks such as braille, it isdifficult to operate through a capacitive touch screen without
seeing and just after a quick look at the screen. We haveproposed a new operation method called inverse tap (iTap) for
capacitive touch panels [1]. iTap is judged as a tap operation
when the finger leaves the screen and touches it again. User
can find the point of operation by the tactile marks withoutlooking at the screen, and perform operation equivalent totapping. In this paper, we propose a new additional method
called “two-finger inverse tap”, and attempt to diversify theoperation options for a single operation point.

Fig. 1: An experiment
TABLE I: Noraml tap
subject
unsuccesssuccessful

A08

subject
unsuccesssuccessful
two finger
one finger

A0963

II. T WO FINGER I TAPWhen the following operations are performed, they are
judged as two finger iTap operations.
1) Touch a screen with two or more fingers
2) Move fingers to find the point to operate while touching3) Release one finger from the screen at the point
4) Release the other finger within a certain distance5) Touch one finger the same point within a certain time6) Touch another finger the same point within a certain time
The above 3 , 4 and 5 , 6 are proceeded almost simultaneously.
The order of the two fingers (positions) when releasing andtouching is not important. In this method, both following twostates are considered as no-operation states: one is the state
when a finger is away from a screen, and another is the state
when it is touching a screen too. Of course normal tap andswipe operations are disabled. In addition, a physical marks
such as braille will be placed on the touch screen.
III. E XPERIMENT AND C ONCLUSION
We conducted a comparison experiment between a normaltap and a two finger iTap with a blind-folds. The subjects
repeat following steps in one minute: take an operation task(ex. turn-up temperature), and then execute the task, andreport. We record the number of times of correct and wrong
operation (Fig. 1). The number of successful and unsuccessful
button presses are shown in Table I and Table II. Note that theB
110C
39D
410

E
410F
56G
57

average
3.12
8.57

TABLE II: Two finger iTapB01192

C01082D013121E0
10100F01091G01183

average
010.57
8.86
1.71

number of successful in Table II includes not only two finger
iTap, but also one finger iTap. There were many operations
at the wrong buttons for normal tap operations. On the otherhand, there was no operation at the wrong button position
for iTap operations. Then the number of successful iTap wasexamined. About 15% of them were judged as one finger
iTap. The subjects may not have been accustomed to the twofinger iTap operation. However since more than 80% of theoperations were performed correctly by the two finger iTap,
it is expected to improve easily. In the future, we would liketo consider the new method such as equivalent to swipe thatmakes easier operation in the blind condition.
ACKNOWLEDGMENT
This work was supported in part by JSPS KAKENHI Grant
Number JP20K11918.
R EFERENCES[1] Kenji Funahashi. Hayato Maki. Yuji Iwahori “Novel tap operation oncapasitive touch screen for people with visual impairment”, ICAT-EGVE
2020 Posters and Demos, pp. 3–4, December 2020.