Improving 3D photogrammetry models through spectral imaging: Tooth enamel as a case study

Abstract

Reflective or translucent materials are a challenge to digitize in 3D. Results are better with a matt coating although objects from museum collections are often too fragile or too valuable to be treated in this way. It is therefore essential that alternative solutions are found. This study analyzed spectral photogrammetry as a possible solution. Spectral photogrammetry is an emerging technique which uses images at different wavelengths to create 3D models. Tooth enamel is a challenging material to digitize. Six sets of teeth were photographed at different wavelengths. The results showed that the quality of the models enamels parts improved when taken with ultraviolet wavelengths whilst models were less accurate when photogrammetry was performed with the red and infrared spectrum. This can be explained by the optical properties of enamel. This study demonstrates that knowing the optical properties of a material beforehand could help future photogrammetric digitization of challenging materials.

Teaching Ichthyology Online with a Virtual Specimen Collection

“…Highly reflective specimens (marine hatchetfishes such as Argyropelecus) bounce back too much light and confuse the scanner as soon as its perspective changes. Coating specimens with an opaque, neutrally colored powder such as chalk dust (Mathys et al, 2015), or the alternate digitization technique of photogrammetry (Mathys et al, 2019), may offer feasible paths forward for digitization of these challenging specimens.…”

3d Digitalization and Visualization of Archaeological Artifacts With the Use of Photogrammetry and Virtual Reality System

“…In order to obtain 3D models of high metric precision mesh and maximum colour fidelity textures macrophotography technique was proposed saving costs and processing time (Antinozzi et al, 2020;Marziali et al 2017;Clini et al, 2016). To solve the problem of reflective or translucent materials another study analysed spectral photogrammetry as a possible solution (Mathys et al, 2019). Considering all these issues, in the following sections the instruments, the techniques and the methodology both for the acquisition and the processing of the data are presented according to the selected case studies.…”

Eliminating Temporal Illumination Variations in Whisk-broom Hyperspectral Imaging

“…Hyperspectral imaging provides a spectrum at each pixel in the image of a scene, providing rich color information of the scene. Much progress has been made in both hyperspectral imaging devices (Shmilovich et al, 2020) and their applications, such as photogrammetry (Mathys et al, 2019), pigment recognition (Cucci et al, 2011), and painting analysis (Cucci et al, 2013). Many of the applications require high spectral-resolution (2 nm bins or even shorter, according to (Cucci et al, 2013).…”