Video Communication Environment Supporting Group Discussion between Separate Sites

当一个小组被分在不同的地方时，通过电话会议系统举行热烈的讨论是困难的。这项研究的目的是确定一个合适的视频交流环境，并开发一个支持参与者之间自由对话的系统，无论演讲者和对话者是否共用一个房间。有人认为，重要的是不仅可以观看演讲者S的面部表情并在屏幕上与某人进行眼神交流，而且还可以观看非演讲者的面部表情和远程站点上的人之间的互动。然而，很难提供许多视频图片，包括每个参与者的全貌和整体视图。此外，使用多个摄像头并移动它们可能会非常分散用户的注意力。开发、评估和改进了一个使用全向摄像头的新型电话会议系统原型。该相机配备了一个全景半球形镜头，可以提供环状的圆形图像。在第一个版本中，全景图像是由一个环形的圆形图像制成的。文中还给出了用单向相机拍摄的长镜头图像。在第二个版本中，单向摄像头被编程为对焦和变焦到扬声器上。在最后一个版本中，使用了高清晰度全向摄像头来提供全脸的高清晰度图像。在一个地方最多可有8人参加讨论。该系统在心理健康小组咨询中进行了测试。坐在圆桌旁的参与者可以相互交谈，也可以与远程教师交谈，而不会感到不安。讲师还可以分析参与者的面部表情、行为和互动。验证了该系统的实用性和可用性。

When a group is divided in separate places, holding a lively discussion through a teleconference system is difficult. The aim of this research is to determine a suitable video communication environment and develop a system supporting free conversation among participants, regardless of whether a speaker and a respective interlocutor share the same room or not.Some three-member groups were asked to use a conventional system with several different camera views and to give their preferences. It was suggested that it was important not only that one could watch speaker' s facial expression and have eye contacts with someone on the screen, but that one could also watch non-speakers' facial expressions and interactions among the people on the remote site. However, it is difficult to provide many video pictures including full faces of every participant and an overall view. Also, using several cameras and moving them can be very distractive to users.A prototype of a new teleconference system using an omni-directional camera was developed, evaluated and improved. The camera is equipped with a hemispherical lens with all-round view which provides a ringed circle image. In the first version, a panorama image was made from a ringed circle image. A long shot image taken by a uni-directional camera was also given. In the second version, the uni-directional camera was programmed to focus and zoom on a speaker. In the last version, a high-definition omni-directional camera was employed to provide a high-definition image of full faces. Up to 8 persons can attend the discussion in one place.The system was tested in mental healthcare group counseling. Participants sitting at a round table could talk with each other and with the remote instructor without feeling disturbed. The instructor could also analyze facial expressions, behaviors and interactions of the participants. Usefulness and usability of the system was verified.