In the Head Mounted Display(HMD) system, there is an item called dynamic characteristics such as latency takes for the motion to be reflected on display and motion wave distortion caused by motion estimation. It is said that the difference between the user's sense of motion and visual information due to this deterioration of dynamic characteristics is the factor of virtual reality sickness. Therefore, the dynamic characteristics are an important item of HMD. The final purpose of this research is to establish a method for measuring the dynamic characteristics of HMD. In this paper, we examined whether our proposed simultaneous subjective observation method is valid for the parallel movement and measured dynamic characteristics under various conditions. In conclusion, the method had enough precision to measure the dynamic characteristics of an HMD in the parallel movement and could be applied to various usage situation.

It has been shown that latency from a virtual reality (VR) user's motion to the display output leads to VR sickness, and in turn decreases the task performance. However, the effects of small delays under 13 ms have not been investigated as the VR systems have not been able to achieve these small latency values. The purpose of this study is to reveal the effects of small latencies on head mounted display users. The subjects in this study were asked to simply and stably stand on a force plate with one foot. The speed of body sway was measured with several lags, from 1 ms to 66 ms, using an Oculus Rift DK2. The results showed that the sway speed increased monotonically with increase in the latency values. The sense of balance is regarded as a relatively direct index of quality of a VR system, including the effects of lag.

Latency is an important specification of the Head Mounted Display (HMD). In this paper, the authors proposed the measurement methods to evaluate the average latency as well as the effects/ side effects of the lag compensation. The Oculus Rift DK2 was selected for measurement. The results showed that the average latency of an DK2 without compensation was about 26.3 ms and that with full compensation was 1 ms. The rest part of the dynamic response was observed and evaluated by subtracting the measured latency from the observed trajectory. The side effect of Timewarp was observed as the spike like angular error.

In the virtual reality system, accurate time management is necessary to maintain the correct relation between the displayed image and the users' motion by the latency compensation. The timestamp concept is effective in managing the timing of the display and sensing device. For time stamping, a unified time axis is necessary among the devices and the PC. In this paper, a time synchronization system via USB was developed. This prototype was proved to have accuracy below 20 μs among multiple sensors.

So called "false image projector" with a novel notion "retrotransmission" is proposed and early prototype will be shown in the demo. This article explains the other research activities of authors' lab as well.

A small, hand-held laser projector is developed using a MEMS scanning mirror. The vertical scan is done by the vibrating mirror and the horizontal scan is done by the user’s action to swing this projector. The prototype is equipped with the photo sensor and barcode reader circuit module to identify the real object with the retroreflective barcode. When the user swing this projector, projector begin to search the object with barcode ID, and when the projector detect such object, the annotation associated with the object’s ID is displayed.

This paper presents tangible interaction techniques for fine-tuning one-to-one scale NURBS curves on a large display for automotive design. We developed a new graspable handle with a transparent groove that allows designers to manipulate virtual curves on a display screen directly. The use of the proposed handle leads naturally to a rich vocabulary of terms describing interaction techniques that reflect existing shape styling methods. A user test raised various issues related to the graspable user interface, two-handed input, and large-display interaction.

The aim of this study is to explore the feasibility of multiple display environment technology in the real world. In this paper, the wearable projector, with an infrared camera and light source, is used in combination with retro-reflective screens. The visible image and infrared light are projected to the screen and reflected back to the user's eye and the infrared camera. The screen location and the user's fingertip position are calculated using image processing to enable the interaction. Several examples or demonstrations have been constructed to show the usage of this configuration. The screen functions as both the visible screen and the high-gain infrared marker at the same time. Owing to high-reflection gain of retro-reflective screens, a small, lightweight projector can be used. Also, the high contrast between the screen and the other environmental object in the captured infrared image decreases the difficulty of image processing.

A head-mounted display (HMD) system suffers largely from the time lag between human motion and the display output. The concept of a reflex HMD to compensate for the time lag is proposed and discussed. Based on this notion, a prototype reflex HMD is constructed. The rotational movement of the user's head is measured by a gyroscope, modulating the driving signal for the LCD panel, and this shifts the viewport within the image supplied from the computer. The derivative distortion was investigated, and the dynamic deformation of the watched world was picked up as the essential demerit. Cylinderical rendering is introduced to solve this problem and is proved to cancel this dynamic deformation, and also to decrease the static distortion.