Ansari-Asl Majid, Barbieri Markus, Obein Gaël, Hardeberg Jon Yngve
Department of Computer Science, Norwegian University of Science and Technology, 2815 Gjøvik, Norway.
Barbieri Electronic snc, 39042 Bressanone, Italy.
J Imaging. 2024 Feb 23;10(3):55. doi: 10.3390/jimaging10030055.
The application of materials with changing visual properties with lighting and observation directions has found broad utility across diverse industries, from architecture and fashion to automotive and film production. The expanding array of applications and appearance reproduction requirements emphasizes the critical role of material appearance measurement and surface characterization. Such measurements offer twofold benefits in soft proofing and product quality control, reducing errors and material waste while providing objective quality assessment. Some image-based setups have been proposed to capture the appearance of material surfaces with spatial variations in visual properties in terms of Spatially Varying Bidirectional Reflectance Distribution Functions (SVBRDF) and Bidirectional Texture Functions (BTF). However, comprehensive exploration of optical design concerning spectral channels and per-pixel incident-reflection direction calculations, along with measurement validation, remains an unexplored domain within these systems. Therefore, we developed a novel advanced multispectral image-based device designed to measure SVBRDF and BTF, addressing these gaps in the existing literature. Central to this device is a novel rotation table as sample holder and passive multispectral imaging. In this paper, we present our compact multispectral image-based appearance measurement device, detailing its design, assembly, and optical considerations. Preliminary measurements showcase the device's potential in capturing angular and spectral data, promising valuable insights into material appearance properties.
具有随光照和观察方向而变化的视觉特性的材料的应用已在从建筑、时尚到汽车和电影制作等不同行业中得到广泛应用。应用范围的不断扩大和外观再现要求强调了材料外观测量和表面表征的关键作用。此类测量在软打样和产品质量控制方面具有双重益处，可减少误差和材料浪费，同时提供客观的质量评估。已经提出了一些基于图像的设置，用于根据空间变化的双向反射分布函数（SVBRDF）和双向纹理函数（BTF）来捕获具有视觉特性空间变化的材料表面外观。然而，在这些系统中，关于光谱通道和逐像素入射反射方向计算的光学设计的全面探索以及测量验证仍然是一个未被探索的领域。因此，我们开发了一种新颖的基于多光谱图像的先进设备，旨在测量SVBRDF和BTF，以弥补现有文献中的这些空白。该设备的核心是一个新颖的旋转台作为样品架和被动多光谱成像。在本文中，我们展示了我们基于多光谱图像的紧凑型外观测量设备，详细介绍了其设计、组装和光学考虑因素。初步测量展示了该设备在捕获角度和光谱数据方面的潜力，有望为材料外观特性提供有价值的见解。
