CAREER: Practical 3D Model Acquisition

尽管图形硬件的性能大幅提高，但由于创建或获取3D内容的困难，大多数用户对3D图形的使用仍然受到限制。廉价、易用的3D扫描系统的广泛使用将有助于弥合这一“内容鸿沟”，影响范围从艺术教育和文化遗产保护到建筑和执法等领域。这项研究的目的是从理论上理解基于三角测量的3D扫描系统，并设计出灵活、坚固、廉价和易于使用的新型3D扫描仪。作为一个具体的例子，该项目涉及将3D扫描引入小学教室，方法是开发一种扫描系统，该系统可以由乐高摄像头和积木构建，由教师设置，并由四年级学生操作。这项研究的目标是通过让学生创作自己的计算机动画电影来鼓励他们对科学、技术和艺术的早期兴趣。这项研究建立在“时空立体”的框架上，以推广目前使用的许多扫描仪设计，如立体声和激光条纹扫描。对现有和新型扫描仪的分析将由系统执行的处理与被扫描对象的属性(例如深度变化、颜色纹理的存在或不存在以及运动速度)相关联，所述处理包括跨越空间、时间或时空窗口的对应。基于这一分析，开发了新的3D扫描仪设计，这些设计消除了对昂贵的光学元件和电机的需求，同时更适合于广泛的扫描场景。实现了几个具体的应用程序，包括用于小型对象的廉价、高分辨率桌面扫描仪，用于灵活结合多个摄像头和投影仪的建筑内部扫描仪，以及一次捕获整个房间的全向扫描仪。高效稳定的对准算法将每个扫描仪获得的多个扫描组合成完整的3D模型。

Despite dramatic increases in the performance of graphics hardware, the use of 3D graphics by most users remains limited because of the difficulty of creating or obtaining 3D content. The widespread availability of inexpensive, easy to use 3D scanning systems will help bridge this "content gap", with impacts in fields ranging from art education and cultural heritage preservation to construction and law enforcement. The aim of this research is to develop a theoretical understanding of triangulation-based 3D scanning systems and to design new 3D scanners that are flexible, robust, inexpensive, and easy to use. As a specific example, the project involves bringing 3D scanning into elementary school classrooms by developing a scanning system that can be built out of Lego cameras and building blocks, set up by teachers, and operated by fourth graders. The goal is to encourage early interest in science, technology, and arts by letting students create their own computer-animated movies.The research builds upon a framework of "space-time stereo" to generalize many currently used scanner designs, such as stereo and laser stripe scanning. An analysis of existing and novel scanners relates the processing performed by the systems, consisting of correspondence across spatial, temporal, or space-time windows, to properties of the object being scanned (such as depth variation, presence or absence of color texture, and speed of motion). Based on this analysis, new 3D scanner designs are developed that eliminate the need for expensive optics and motors while being more adaptable to a wide range of scanning scenarios. Several specific applications are implemented, including an inexpensive, high-resolution desktop scanner for small objects, scanners for building interiors that flexibly incorporate multiple cameras and projectors, and an omni directional scanner that captures an entire room at once. Efficient and stable alignment algorithms combine the multiple scans obtained by each scanner into complete 3D models.