Evaluating Smartphones Color Fidelity and Metric Accuracy for the 3d Documentation of Small Artifacts

Abstract

<p><strong>Abstract.</strong> Smartphone camera technology has made significant improvements of sensors quality and software camera performance in recent years. Devices as Apple iPhone X and the Samsung Galaxy S9 Plus, allow to reach levels of image resolution, sharpness and color accuracy very close to prosumer SLR cameras, enabling also on-the-fly processing and procedures which were considered impossible to achieve until a few years ago. Starting from these premises, a series of issues and opportunities concerning smartphone application to artifacts documentation will be discussed. In particular, consistency and reliability of both shape and color representation achievable for small-medium artifacts belonging to exhibitions and museum collections. A low-cost, easy-to-use workflow based on low-cost widespread devices will be compared to consolidated digitization pipelines. The contribution focus is based on color accuracy of textured models achievable through smartphones by means of an internally developed application for the achievement of highly reliable developments of raw formats (.DNG) from Apple iPhone X. Color consistency will be calculated in terms of the mean camera chroma relative to the mean ideal chroma in the CIE color metric (ΔE*<sub>00</sub>) as defined in 2000 by the CIE on the CIEXYZ chromaticity diagram.</p>

D3mobile Metrology World League: Training Secondary Students on Smartphone-Based Photogrammetry

“…Now, smartphones are light, portable and thus with us most of the time, which will inevitably stimulate the spontaneous capture of images with recording purposes (Nocerino et al, 2017). Smartphone camera technology has made significant advances in recent years, by incorporating larger sensors and software with an improved performance, reaching levels of image resolution, sharpness and color accuracy very close to DSLR cameras (Gaiani et al, 2019). The increased quality of images leads to obtain improved 3-D results from them, after being processed with photogrammetric desktop-or cloud-based software.…”

The limits of colorimetry in cultural heritage applications

“…Today the CC is used to control the stability of colours in photography, scanning and object acquisition. Nevertheless, different errors occur in colour reproduction, and different works found the CC insufficient to guarantee the robustness of colour reproduction 11,47 . As a consequence, the entire photogrammetric process and object digital reconstruction can be unfaithful.…”

“…The range of digital technologies spread widely the use of colorimetry in cultural heritage. Scientists approached reproducing an objects colour in digital form for two‐dimensional (2D) or three‐dimensional (3D) reconstruction for conservation and valorisation purpose, 8,9 to help the archiving process 10 and using different devices 11 . Furthermore, the archives are going more and more through the digitisation of the conserved materials.…”

“…Scientists approached reproducing an objects colour in digital form for two-dimensional (2D) or three-dimensional (3D) reconstruction for conservation and valorisation purpose, 8,9 to help the archiving process 10 and using different devices. 11 Furthermore, the archives are going more and more through the digitisation of the conserved materials. This is supported by large national and international digitisation campaigns of documents, photographs and audiovisual materials.…”

A Critical Comparison of 3D Digitization Techniques for Heritage Objects

“…Metric evaluations have been carried out regarding heritage objects, by Remondino et al [22], Nabil and Saleh [23], Galizia et al [24], Bianconi et al [25] for SfM software, by Evgenikou and Georgopoulos [26] and Menna et al [27] on scanning versus SfM photogrammetric software approaches and by Kersten et al [28,29] and Morena et al [30] for portable/handheld scanners. Additionally, due to recent significant improvements in mobile phone camera technology, regarding sensors' quality and camera software performance, smartphone cameras have been evaluated for the posttexturing of models from active sensors and for the direct image-based metric modeling of heritage objects [31][32][33]. Despite frequent assessments concerning the aforementioned digitization techniques being found in bibliography, they quickly become outdated due to the rapid technological developments.…”