The Multimodal Approach of Rendering Soft Textures on Touch Displays

与电脑相比，触控设备由于能够运行大量任务和便携，正在成为我们日常生活中最重要的附件之一。如今，它们是各种电子设备上使用的方便、廉价和可编程的输入工具。然而，越来越多的应用程序和软件已经开始包括复杂和关键的任务，这些任务大多是在仅基于视觉提示的显示器上操作的。然而，为了更可靠和舒适的人与显示器交互，应该及时实施精确的触觉反馈到触摸屏。例如，在显示器上再现触觉质感已经成为触觉领域的一个新兴课题。在过去的十年中，里程碑式的研究引入了基于测量的绘制技术，能够通过记录表面信息来创建逼真的触觉纹理。然而，这种方法不可避免地将感知上的冗余数据与必要的纹理信息混合在一起。因此，这项研究的第一个目标是确定触觉的知觉极限，以便能够驱动必要的信息量来在显示器上创造看似合理的质感。这一目标也将使用听觉反馈进行研究，因为感知纹理是一个复杂的触觉和听觉模式的融合过程。在此之前，各种研究表明听觉反馈对触觉纹理知觉的影响。由于这一效应，将评估听觉反馈对进一步简化触觉数据和增强振动的似然性的影响。这项研究的另一个担忧来自这样一个事实，即触摸屏由于其固定的玻璃表面而受到触觉反馈的限制，而不是传统的动觉设备。最近，一些研究介绍了触摸屏上动觉反馈的不同实现思想，这些研究仅使用简单的僵硬模型验证了它们的驱动机制。除了这些动觉显示，甚至传统的力反馈设备也被用来渲染软材料，使用线性二阶刚度模型，该模型通常用于复制环境中的动力学。另一方面，软材料由于其非线性的粘弹性性质，不能用线性模型很好地描述。因此，在任何动觉装置上都可能不会产生精确的柔软度效果。因此，本研究的第二个目标是在触摸屏上再现与各种软材料相对应的逼真柔和效果。这一目标将通过研究人体的僵硬感觉和各种非线性的僵硬模型来精确地模拟柔度响应，避免不必要的复杂模型产生不可感知的细节。在本研究的最后，将建立基于感知的多通道软纹理渲染策略。

Touch devices are becoming one of the most significant accessory of our daily lives due to being capable of running numerous tasks and being portable as opposed to computers. Nowadays, they are easily accessible, cheap and programmable input tools being used at various electronic devices. However, increasing number of applications and software have begun including complicated and critical tasks, and these tasks have been mostly operated on displays based on only visual cues. However, for more reliable and comfortable human-display interaction, precise haptic feedback should be promptly implemented to touch displays. For instance, reproducing tactile texture sensation on displays has been an emerging topic in the haptic field. In the last decade, landmark studies introduced measurement-based rendering techniques that enabled creating realistic haptic textures by recording surface information. However, such methods inevitably blend perceptually redundant data with the necessary texture information. Therefore, the first goal of this study is to determine the perceptual limits of the tactile sensation so that necessary amount of information can be driven for creating plausible texture feeling on displays. This goal will be also investigated using auditory feedback due to the fact that perceiving a texture is a complex fusion process of tactile and auditory modalities. Previously, various studies showed the effect of auditory feedback on tactile texture perception. Thanks to this effect, the influence of auditory feedback on further tactile data simplification and augmenting the plausibility of vibrations will be evaluated. Another concern of this study arises from the fact that touch displays have been limited with tactile feedback due to their fixed glass surface as opposed to traditional kinesthetic devices. Lately, several studies introduced different implementation ideas of kinesthetic feedback on touch displays, and these studies validated their actuation mechanisms using only simple stiffness models. Apart from these kinesthetic displays, even traditional force feedback devices have been used to render soft materials using linear second-order stiffness model which is commonly used to replicate the dynamics in the environment. On the other hand, soft materials cannot be well-described using linear models due to their nonlinear viscoelastic properties. Because of this, precise softness effect may not be generated on any kinesthetic devices. Thus, the second goal of this study is to reproduce realistic softness effect corresponding to various soft materials on touch displays. This aim will be realized by investigating human stiffness sensation and various non-linear stiffness models to mimic softness response precisely avoiding unnecessary complex models producing unperceivable details. At the end of this study, perception-based multimodal soft texture rendering strategy will be established.