Takashi Yamazoe

Evaluation of stereoscopic medical video content on an autostereoscopic display for undergraduate medical education

Introduction: An increasing number of surgical procedures are performed in a microsurgical and minimally-invasive fashion. However, the performance of surgery, its possibilities and limitations become difficult to teach. Stereoscopic video has evolved from a complex production process and expensive hardware towards rapid editing of video streams with standard and HDTV resolution which can be displayed on portable equipment. This study evaluates the usefulness of stereoscopic video in teaching undergraduate medical students. Material and methods: From an earlier study we chose two clips each of three different microsurgical operations (tympanoplasty type III of the ear, endonasal operation of the paranasal sinuses and laser chordectomy for carcinoma of the larynx). This material was added by 23 clips of a cochlear implantation, which was specifically edited for a portable computer with an autostereoscopic display (PC-RD1-3D, SHARP Corp., Japan). The recording and synchronization of left and right image was performed at the University Hospital Aachen. The footage was edited stereoscopically at the Waseda University by means of our original software for non-linear editing of stereoscopic 3-D movies. Then the material was converted into the streaming 3-D video format. The purpose of the conversion was to present the video clips by a file type that does not depend on a television signal such as PAL or NTSC. 25 4th year medical students who participated in the general ENT course at Aachen University Hospital were asked to estimate depth clues within the six video clips plus cochlear implantation clips. Another 25 4th year students who were shown the material monoscopically on a conventional laptop served as control. Results: All participants noted that the additional depth information helped with understanding the relation of anatomical structures, even though none had hands-on experience with Ear, Nose and Throat operations before or during the course. The monoscopic group generally estimated resection depth to much lesser values than in reality. Although this was the case with some participants in the stereoscopic group, too, the estimation of depth features reflected the enhanced depth impression provided by stereoscopy. Conclusion: Following first implementation of stereoscopic video teaching, medical students who are inexperienced with ENT surgical procedures are able to reproduce depth information and therefore anatomically complex structures to a greater extent following stereoscopic video teaching. Besides extending video teaching to junior doctors, the next evaluation step will address its effect on the learning curve during the surgical training program.

Ergonomic evaluation of ubiquitous computing with monocular head-mounted display

In this paper, the authors conducted an experiment to evaluate the UX in an actual outdoor environment, assuming the casual use of monocular HMD to view video content while short walking. In conducting the experiment, eight subjects were asked to view news videos on a monocular HMD while walking through a large shopping mall. Two types of monocular HMDs and a hand-held media player were used, and the psycho-physiological responses of the subjects were measured before, during, and after the experiment. The VSQ, SSQ and NASA-TLX were used to assess the subjective workloads and symptoms. The objective indexes were heart rate and stride and a video recording of the environment in front of the subjects face. The results revealed differences between the two types of monocular HMDs as well as between the monocular HMDs and other conditions. Differences between the types of monocular HMDs may have been due to screen vibration during walking, and it was considered as a major factor in the UX in terms of the workload. Future experiments to be conducted in other locations will have higher cognitive loads in order to study the performance and the situation awareness to actual and media environments.

Improved Visibility of Monocular Head-Mounted Displays Through the Bright Control of Backlighting

Monocular head-mounted displays (HMDs) will be a major tool for ubiquitous computing. However, monocular HMD visibility causes a decrease in the light received from the environment. Fluctuating light from the environment strongly affects the visibility of images presented on the monocular HMD. In the present study, we have studied a method for controlling HMD backlighting to improve visibility at the wearing a monocular HMD under variable lighting conditions. Three backlight control patterns were developed from Experiment I as psychophysical measurements, and their validities were subjectively evaluated in Experiment II. The results suggest increased visibilities at wearing a monocular HMD when controlling the backlight. Moreover, the rules for backlighting control are based on psychophysical theory.

LCD Backlight Control for Visibility of Monocular Head-Mounted Displays

Monocular head-mounted displays (HMD) are expected as a core device for ubiquitous computing. However, monocular HMD can decrease the visibility by environment light. High luminance environment light makes high contrast between the environment and images presented by monocular HMD. This situation causes perceptional lost of the images. In this study, the authors examined a LCD backlight control method for the visibility of monocular HMD in various light situations. Four kinds of backlight control patterns were obtained by a psychophysical measurement, and the validity was also subjectively evaluated. This paper reports the results of the evaluation and discusses on the suitable backlight control in terms of human factors. levels, 50cd/m 2 , 150cd/m 2 , 250cd/m 2 , 350cd/m 2 . Because, LCDs luminance stable zone was up 33cd/m 2 to under 354cd/m 2 . Four levels illuminant made by Macromedia Flash 8 Professional. Monocular HMD (Nikon, 264cd/m 2

Ergonomic evaluation system for stereoscopic video production

This paper describes the trial development of an ergonomic evaluation system for stereoscopic video production. The purpose of the system is to quantify the parallax distribution of stereoscopic images and evaluate their viewing safety and comfort. The authors processed the images to extract the optical flow between the right and left images. The reference values for safety and comfort were obtained from two subjective evaluation and precedent studies. This paper reports the results of the experiments and the development of a prototype evaluation system.

Psycho-physiological effects of head-mounted displays in ubiquitous use

In this study, two experiments were conducted to evaluate the psycho-physiological effects by practical use of monocular head-mounted display (HMD) in a real-world environment, based on the assumption of consumer-level applications as viewing video content and receiving navigation information while walking. In the experiment 1, the workload was examined for different types of presenting stimuli using an HMD (monocular or binocular, see-through or non-see-through). The experiment 2 focused on the relationship between the real-world environment and the visual information presented using a monocular HMD. The workload was compared between a case where participants walked while viewing video content without relation to the real-world environment, and a case where participants walked while viewing visual information to augment the real-world environment as navigations.

P‐43: Effects of Changing Image Size on Depth Perception Using a Floating 3‐D Display

A floating-image display produces 3-D effects using a lens system that makes an image appear to float in the air. The authors examine the effects on depth perception and asthenopia of viewing a floating image that continuously changes in size. The results of the experiments suggest that viewers perceive the floating image to be moving back and forth as the image size changes despite the fact that the images actual position does not change. Monocular depth cues, especially changes in size, enhanced the 3-D effects of images presented on the floating-image display.

Ergonomic approaches to content creation for 3D displays

Abstract This paper presents ergonomic approaches to editing and evaluating content for 3D displays. Two systems, a nonlinear editing system and an evaluation system, were developed to improve viewing safety and comfort for 3D content observ ers and provide better usability for the creators from the viewpoint of ergonomics.