Visualising Animal Hard Tissues

从最早的时候起，人们就使用坚硬的骨骼组织，如骨、鹿角、象牙、角、鲸骨和龟甲作为原材料，创造从简单的工具到微妙和令人回味的艺术作品的几乎所有东西。加工这些原材料会极大地改变它们的外观，而腐烂过程可能会使它们几乎面目全非。如今，动物硬组织几乎完全被金属合金和合成塑料取代了作为人工制品的原材料，野生动物保护方面的担忧使一些人无法获得和接受。随着这些原材料的流失，人们不再熟悉它们的特征和性质，这对那些从事历史和史前文物工作的人以及对非法贩运的受保护材料的检测构成了挑战。然而，对这些材料的正确鉴定对于理解这些物品的文化意义、保存需求和真实性是至关重要的。目前已经在进行研究，通过对视觉标准和分析技术的整理、评估和验证来完善和制定鉴定方案。这项工作在提高我们的信心方面取得了长足的进步，例如，识别不同种类的象牙制成的物品，或者区分角质或塑料制成的真假龟甲。使用低倍显微镜，通过揭示材料结构和降解模式，可以在不需要采集毁容样本的情况下完成这一任务，并且不会对对象造成风险。但是，与木材一样，这些都是复杂的3D材质，其外观和行为可能完全不同，具体取决于它们的工作方式以及对象表面显示的方面。为了正确地解释证据，有必要根据材料的自然结构来理解物体的方位。当这些材料的类似加工样品无法与正在研究的对象进行比较时，这尤其困难。即使这些原材料中有一些，如犀牛角，准备加工标本也是非法的(在道德上也是有问题的)。使用印刷或网络资源，通过2D图表和照片来传达这些复杂结构的细节，成功在很大程度上取决于用户以3D思维的能力，并不总是导致正确的识别。为了克服这些问题，该项目将开发一个基于网络的资源，用于对这些动物组织的结构进行3D可视化。其核心将是每种原材料的完全可旋转的3D照片真实感图像、其结构的3D图以及揭示内部形状和结构的3D X光(CT扫描)。放大后，材料的表面可以在不同的尺度上进行探索，通过链接到一系列放大倍数的照片来查看材料的表面，这些照片显示了当材料以不同方向切割、以不同方式加工、断裂、老化或降解时显示的结构。一旦识别了正确的材料，就可以通过将在对象表面上显示的特征与模型中指示的特征相匹配来相对于3D模型的框架来定向对象的图像。这将有助于了解原材料是如何利用的，并提供对所用原始组织大小的估计，例如为雕塑提供材料所需的象牙的最小尺寸。在在线教程的支持下，这一交互式可视化资源不仅将提高材料识别的准确性，而且将成为研究人员探索这些原材料在所有时间段和地理区域的文物制造中的使用方式的宝贵工具，无论是功能工具、宗教物品还是美术作品。

From earliest times people have used hard skeletal tissues, such as bone, antler, ivory, horn, baleen (whalebone) and tortoiseshell, as raw material to create almost everything from simple tools to subtle and evocative works of art. Working these raw materials can greatly change their appearance and decay processes can render them almost unrecognisable. Today animal hard tissues have almost entirely been replaced as raw material for artefacts by metallic alloys and synthetic plastics, and wildlife conservation concerns have made some unavailable and unacceptable. With the passing of these raw materials, familiarity with their characteristics and properties has been lost, posing a challenge for those who work with historic and prehistoric artefacts, and to the detection of illegally trafficked, CITES protected materials. The correct identification of these materials is, however, fundamental to understanding the cultural significance, preservation needs and authenticity of these objects.Research is already in hand to refine and develop identification protocols through the collation, evaluation and validation of visual criteria and analytical techniques. This work has made great strides in improving our confidence in recognising, for instance, objects made in different species of ivory or in separating real tortoiseshell from fakes in horn or plastic. Using low-power microscopy, this can be done without the need to take disfiguring samples and at no risk to the object, by revealing the materials structure and patterns of degradation. However, like wood, these are complex 3D materials that can look and behave entirely differently depending on how they are worked and which aspects are revealed in the surfaces of an object. To interpret the evidence correctly it is necessary to understand the orientation of the object in terms of the material's natural structure. This is particularly difficult when similarly worked specimens of these materials are not available for comparison with the object being studied. Even if some of these raw materials, such as rhino horn, were available, it would be illegal (and questionable ethically) to prepare worked specimens. Using printed or web resources, illustrated by 2D diagrams and photographs to convey the detail of these complex structures, success largely relies on the ability of the user to think in 3D, and will not always lead to the correct identification. To overcome these problems, this project will develop a web-based resource for the 3D visualisation of the structures of these animal tissues. At its core will be a fully-rotatable 3D photo-realistic image of each raw material, a 3D diagram of its structure and 3D X-rays (CT scans) revealing the internal shape and structure. Zooming-in, the surface of the material can be explored at different scales with 'hot-spots' linking to photographs at a range of magnifications showing the structures revealed when it is cut in different directions, worked in different ways, fractured, aged or degraded. Once the correct material has been identified, it will be possible to orientate images of the object against the framework of the 3D model by matching the features revealed on the surface of an object with those indicated in the model. This will aid understanding of how the raw material was utilised and provide estimates of the size of the original tissue used, such as the minimum dimensions of the elephant tusk required to provide the material for a sculpture. Supported by on-line tutorials, this interactive visualisation resource will not only improve the accuracy of materials identification but will be an invaluable tool for researchers exploring the way that these raw materials have been used in the manufacture of artefacts, whether functional tools, devotional objects or fine art, across all time periods and geographical zones.