Facilitating rearward visibility by controlling eye
direction in HMD viewing of panoramic images
Seitaro Inagaki

Kenji Funahashi

Nagoya Institute of Technology, Japans.inagaki.706@stn.nitech.ac.jp

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

Index Terms—panoramic image, eye direction control, rearward visibility

real eye direction the same as up to 45 degrees, and it isexaggerated from 45 degrees.

I. I NTRODUCTION

III. E XPERIMENT AND C ONCLUSION

The development of HMDs for home use has progressed,and many people can now enjoy VR easily at home. Most VRservices for 360-degree image viewing are used in a seatedposition. However, it is difficult for humans to look rearward
in a seated position while rotating the neck and hips [1].
Although it is easy to look rearward when sitting in a swivel
chair, it has been reported that the rotation of the seat surface
amplifies the user’s body movements and increases sensory
discrepancy when viewing a 360-degree video with an HMD[2]. In this paper, we propose a new method that enables
rearward visibility while sitting in a chair. The direction inwhich you are looking is called the eye direction. A rearward
scenery that is different from the actual eye direction will bepresented on the HMD to enable to look rearward withoutlifting the hips.
II. E YE D IRECTION E XAGGERATION M ETHOD

We conducted an experiment to see if there were any
problems with exaggeration. In the experiment, we preparedsome different exaggeration patterns. Subjects were asked totry our new method using an HMD and fill out a questionnaire.
In the questionnaire, we asked about “operability” and “discomfort”. In addition, they answered about their impressionsof the usefulness of our method. They all said that it wasdifficult to look rearward in normal condition, but exaggeration
made it easier to look rearward. It was confirmed that thismethod facilitates rearward visibility and makes it easy toenjoy the scenery in all directions. As a future work, wewould like to survey what kind of exaggeration patterns areappropriate, further suppress VR sickness and find a betterway to exaggerate that is closer to the actual use of VR.

The actual eye direction regardless of the scenery displayedon the HMD is called the “real eye direction” and the directionof the scenery displayed on the HMD by the program is called
the “virtual eye direction”. Although virtual eye direction isoriginally same as real eye direction, the angle of the real eye
direction is exaggerated to display scenery on the HMD witha virtual eye direction different from it (fig.1). The graph isan example of the relationship between the real eye direction
and the virtual eye direction. The virtual eye direction is theThis work is supported in part by JSPS KAKENHI Grant
Number JP20K11918.

ACKNOWLEDGMENTR EFERENCES[1] K.Yonemoto, S.Ishigami and T.Kondo, “Joint range of motion display
and measurement methods”, The Japanese Journal of Rehabilitation
Medicine, vol.32, No.4, pp.207–217, 1995
[2] Y.Banchi, K.Yoshikawa and T.Kawai, “Effect of chair swiveling on user
experience during 360-degree images viewing using a HMD”, TVRSJ,
vol.23, No.3, pp.217–227, 2018180

Scenery seen when the real eye
direction is 30 degrees

Scenery seen when the real eye
direction is 60 degrees

Scenery seen when the real eye
direction is 90 degrees

Sensor0°

165
150

Real eyedirection

Virtual eyedirection

60°

92°

HMD

Angle of the virtual eye direction

Scenery seen when the real eye
direction is 0 degrees

135120
10590
7560
4530
150-180°

Angle of eye direction 0°

30°

60°

(a) Panoramic image

90°

180°

180°
Rearward(b) 60-degree angle in the real eye direction

Fig. 1: Example of our method

01530

4560

7590

Angle of the real eye direction(c) Exaggerated pattern