Avatar's Gaze Control to Facilitate Conversational Turn-Taking in Virtual-Space Multi-user Voice Chat System
Avatar's Gaze Control to Facilitate Conversational Turn-Taking in Virtual-Space Multi-user Voice Chat System
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Avatar 的视线控制促进虚拟空间多用户语音聊天系统中的对话轮流
DOI：
10.1007/11821830_47
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Y. Nakano
中科院分区：
文献类型：
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作者：
Ryo Ishii;Toshimitsu Miyajima;K. Fujita;Y. Nakano
为了促进共享虚拟空间语音聊天环境中的多方对话，我们提出了一种用于多方对话中轮流的化身注视行为模型，以及一种具有使用用户话语信息自动控制化身注视方向功能的共享虚拟空间语音聊天系统。利用话语信息实现了易于使用的自动注视控制，无需眼动跟踪摄像头或手动操作。在我们的凝视行为模型中，对话被分为三种状态：说话期间、说话后和沉默。对于每个状态，化身的注视行为都是基于概率状态转换模型来控制的。
先前的研究表明，凝视具有选择下一个讲话者并敦促她/他讲话的能力，而持续的凝视有可能给听众留下令人生畏的印象。虽然明确地将目光从对话伙伴身上移开通常意味着对他人感兴趣，但这种凝视行为似乎可以帮助说话者避免威胁听者的脸部。为了在虚拟空间头像中表达对脸部威胁较小的视线，我们的模型引入了模糊视线：头像的视线比用户眼睛位置低五度。因此，在说话期间，化身是使用概率状态转换模型来控制的，该模型在三种状态之间转换：目光接触、模糊凝视和移开目光。预计模糊的目光会减少令人生畏的印象并促进对话轮流。在发言后状态下，发言者头像会保持目光接触几秒钟，以敦促下一个发言者开始新一轮。这是基于对真实面对面对话的观察。最后，在安静状态下，角色的注视方向会随机改变，以避免给人一种恐吓的印象。
在我们的评估实验中，十二名受试者被分为四组，并要求与虚拟人物聊天并使用李克特量表回答他们的印象。至于说话过程中的状态，在自然性、恐吓印象减少和轮流促进方面，与仅模糊凝视、仅看别处和仅固定凝视模型相比，由模糊凝视和移开目光组成的过渡模型显着有效。在发话后状态下，与固定注视方法相比，任何注视控制方法在促进轮流转换方面都显着有效。评估实验证明了我们的化身注视控制机制的有效性，并表明基于用户话语的注视控制有助于虚拟空间语音聊天系统中的多方对话。
Aiming at facilitating multi-party conversations in a shared-virtual-space voice chat environment, we propose an avatar’s gaze behavior model for turn-taking in multi-party conversations, and a shared-virtual-space voice chat system with automatic avatar gaze direction control function using user utterance information. The use of the utterance information attained easy-to-use automatic gaze control without eye-tracking camera or manual operation. In our gaze behavior model, a conversation was divided into three states: during-utterance, right-after-utterance, and silence. For each state, avatar’s gaze behaviors are controlled based on a probabilistic state transition model.
Previous studies reveled that gaze has a power of selecting the next speaker and urge her/him to speak, and continuous gaze has a risk of giving intimidating impression to the listener. Although explicit look-away from the conversational partner generally means interest to others, such gaze behaviors seem to help the speaker avoid threatening the listener’s face. In order to express less-face-threatening eye-gaze in virtual space avatars, our model introduces vague-gaze: the avatar looks at five degrees lower than the user’s eye position. Thus, in during-utterance state, the avatars were controlled using a probabilistic state transition model that transits among three states: eye contact, vague-gaze and look-away. It is expected that the vague-gaze reduces intimidating impression as well as facilitates conversational turn-taking. In right-after-utterance state, the speaker avatar keeps an eye contact for a few seconds to urge the next speaker to start a new turn. This is based on an observation of real face-to-face conversation. Finally, in silent state, avatar’s gaze direction is randomly changed to avoid giving intimidating impression.
In our evaluation experiment, twelve subjects were divided into four groups, and requested to chat with the avatars and answer impressions for them using Likert scale. As for the during-utterance state, in terms of naturalness, intimidating impression reduction and turn-taking facilitation, a transition model consisting of vague-gaze and look-away was significantly effective, compared to the vague-gaze alone, the look-away alone and the fixed-gaze alone models . In the right-after-utterance state, any of the gaze control methods were significantly effective in facilitating turn-taking, compared to the fixed-gaze method. The evaluation experiment demonstrated the effectiveness of our avatar’s gaze control mechanism, and suggested that the gaze control based on the user utterance facilitates multi-party conversations in a virtual-space voice chat system.