Assessment of Stereoscopic Multi-resolution Images for a Virtual Reality System

International audienceA camera and monitor system that projects actual real-world images has yet to be developed due to the technical limitation that the existing cameras cannot simultaneously acquire high-resolution and wide-angle images. In this research, we try to resolve this issue by superimposing images; a method which is effective because the entire wide-angle image does not necessarily need to be of high resolution because of perceptual characteristics of the human visual system. First, we examined the minimum resolution required for the field of view, which indicated that a triple-resolution image where positions more than 20 and 40 deg from the center of the visual field were decreased to 25% and approximately 11% of the resolution of the gaze point, respectively, was perceived as similar to a completely high-resolution image. Next, we investigated whether the participants could distinguish between the original completely high-resolution image and processed images, which included triple-resolution, dual-resolution, and low-resolution images. Our results suggested that the participants could not differentiate between the triple-resolution image and the original image. Finally, we developed a stereoscopic camera system based on our result

認知と行動 : 安全運転を科学する

九州大学公開講座 先端サマーセミナー2015 暮らしに役立つシステム情報科学 : 2015年8月5

認知と行動 : 安全運転を科学する

九州大学公開講座 先端サマーセミナー2015 暮らしに役立つシステム情報科学 : 2015年8月5

The Effect of Reaction Force Feedback on Object-Insert Work in Virtual Reality Environment

It has been reported that the teleoperational efficiency using stereoscopic video images is inferior to the working efficiency of using the naked eye in real environments. One of the causes of this is the deficiency of the amount of information for operators. The big improvement on the working efficiency was shown when tactual feedback was given to operators in addition to the sight information. It is not clear how reaction force information helps the improvement in working efficiency. In this report we investigated the effect of the amount of reaction force feedback under sufficient and insufficient visual informational environments. Subjects were instructed to insert cylinders into the holes on the blocks in the virtual reality environment. The results showed that the force feedback brought about a shorter work completion time and lessened the number of errors. However, there are no significant differences both among the work completion times and the numbers of different amounts of reaction force. This result suggests that the tactual cue is effective to improve task performances of the teleoperation

Hypothesis Relating Arousal Level and Blink Rate

The relation between arousal level and blink rate has not yet been clarified. One of the causes is a difference of the task done by previous study. Visual tasks greatly influence blink rate, therefore, it is necessary to examine the relation between arousal level and blink rate as it pertains to vision. In this study, the relation between arousal level and blink rate was examined through testing the effects that performing visual task and non-visual task (auditory task) had on 12 university students. The index of arousal level was an electroencephalogram (α-index). As a result of the experiment, we proposed hypothesis relating arousal level and blink rate. In this hypothesis, the blink rate decreases as arousal level decreases when arousal level decreases below a certain level. However, with visual tasks, the blink rate tends to temporarily increase as arousal level decrease. And, we also proposed extended hypothesis. In this hypothesis, when arousal level increases markedly, the blink rate also increases

Reaction Time while Driving with Insufficient Headway

As a driver\u27s headway distance becomes shorter, it is necessary to quickly detect the movements of the vehicles ahead. In other words, a driver has to pay close attention to the vehicles ahead. In such situations, it is assumed that the reaction time to vehicles ahead and other obstacles would fluctuate more than when there is a long headway. To clarify the relationships between headway distance and reaction time, we conducted two experiments using a driving simulator. The results showed that the mean reaction times under the short headway distance became shorter than those under the long headway distance, however, the standard deviation of those under the short headway distance was greater. And it clarified that driving under the short headway distance requires more information processing on the part of the driver. These results lead to the conclusion that drivers tend to have more collisions under the short headway distance. This is because the short headway distance makes the drivers\u27 reaction time fluctuate as well as satisfying the condition that the headway distance is shorter than the stopping distance

The Effect of Tactual Feedback by the Vibration Device in Virtual Reality Environment

It has been reported that operating efficiency for teleoperations using stereoscopic video images is lower than that using the naked eye in real environments. Here, the authors tried to improve the human-machine interface of teleoperational system in order to achieve a higher operating efficiency for stereoscopic video images by adding other information. An experiment was carried out under the two following conditions: Condition 1 was only stereoscopic vision. Condition 2 was that tactual feedback was given through a vibration device put on the subject\u27s hand, as one object touched another. The vibration device consisted of a small motor, and vibrated when objects touched each other. The subject\u27s task was to insert a cylindrical object into a round hole. The completion time, when tactual feedback was provided (Condition 2), was shorter than when no additional information was provided (Condition 1). This result leads to the conclusion that the efficiency becomes higher by the vibration device

Fixation Point Measurement with an Ellipsoid Estimation

The fixation point is usually measured with the optic axis of the eye. This method assumes that the relation between the mental direction of view and the direction of the optic axis is mappable with the calibration. In this paper we take up monocular fixation for a static target. In this situation, not only is the relative angle between the visual axis and the optic axis fixed, but also the angle between the visual axis and the mental direction of view are coincident. The accuracy of fixation point measurement would rely on the accuracy of optic axis measurement. We attempted accurate measurement of the optic axis with an ellipsoidal model about the orbit of the pupil center. Consequently, under the condition that the visual field was horizontal 43 and vertical 22 degrees with nine points calibration, the maximum discrepancy between the actual target and estimated fixation point over the field was about 0.7 degrees, which was accurate in comparison with 1.4 degrees which arose from the calibration of the simple plane interpolation method