3D Recording Research Articles

3D audio recording of complex underwater sound fields

In this study, we developed a method to capture underwater sound fields and reproduce them for human listeners, providing an immersive 3D auditory experience. We recorded the sound field with an array of four hydrophones arranged in a tetrahedral structure. The side length of the tetrahedron (around 70 cm) was a compromise between capturing accurately the low frequency pressure gradients and spatial aliasing effects at higher frequencies. Subsequently, we transformed the signals into the domain of spherical harmonics facilitating a representation as first-order Ambisonics that is independent of the recording. For playback on devices such as headphones or loudspeaker systems, we used established decoding routines that enhance the immersive audio experience with techniques such as parametric decoding and diffuse sound field equalization. During an expedition to northern Norway, we recorded the underwater soundscape in deep fjords with vocalizing killer whales and singing humpback whales. The resulting binaural renderings for headphones of these sound scenes are astonishing and sparked interest among scientist, artists and general public. This research also helps to enhance our understanding and perception of these intelligent marine mammals and their unique acoustic underwater world, ultimately aiding in better protecting them from noise pollution.

Tracking 3D motion of instruments in microsurgery: A comparative study of stereoscopic marker-based vs. deep learning method for objective analysis of surgical skills

Background:In microsurgery, integrating motor and visual information is crucial for achieving precise bimanual maneuvers. Computer vision serves as a useful tool for analyzing surgical maneuvers and enhancing situational awareness in medical assistive systems. Furthermore, the combination of deep learning with computer vision shows promise for objectively assessing surgical skills. Methods:This study compared two methods for tracking 3D movement during microsurgery: Mitracks3D, a stereoscopic tracker using color-marked instruments, and a deep learning method for instruments identification based on YOLOv8. Additionally, drawing an analogy between single-camera and new stereoscopic recording systems, 2D and 3D motion signals from microsurgery training videos on the peg transfer task were obtained to analyze surgeons’ psychomotor skills using six motion analysis parameters (MAPs). Results:When comparing the two 3D tracking methods, the motion signals revealed a relative error (ϵ) of less than 10%, with a correlation coefficient (ρ) exceeding 0.9892 ±0.0020, tracking loss below 2.0398%, and instruments detection time under 1 ms for Mitracks3D and 7.09 ±0.62 ms for YOLOv8. When comparing the performance between participants using 2D and 3D signals, statistically significant differences were found in 4 of the 6 explored MAPs. Additionally, a high cosine similarity (cs>0.99) was found between the performance scores of the 6 MAPs, indicating compatibility between the 2D and 3D recording modalities. Conclusions:The deep learning-based approach is as effective as stereo-tracking with markers; both methods produced remarkably similar 3D motion signals. The compatibility in evaluation between 2D and 3D was confirmed. In essence, adopting computer vision methods such as Mitracks3D and YOLOv8 provides a compelling alternative for constructing objective assessment tools for surgical skills.

3D Recording of Palaeolithic Rock Art through Different Techniques: a Critical Comparison and Evaluation

ABSTRACT Palaeolithic graphic activity documentation is essential not only for its preservation and dissemination but also for its scientific analysis. Nowadays, researchers can use advanced techniques such as photogrammetry, lidar, or structured light scanning to record this heritage. However, there is a lack of studies comparing these three technologies. Therefore, this article presents a comparison of these techniques based on three variables: namely, time employed, geometric reconstruction, and resolution. The study examines how these factors affect the final result of the digital recording of rock art. A mold of Rock 11 from Domingo García (Segovia, Spain) and the archaeological panel S.4 from La Salud (Salamanca, Spain) have been used as test control examples. The results indicate that photogrammetry using a DSLR camera is the most efficient technique, providing the necessary reconstruction to obtain scientific data.

Jaw-neck motor function 2 years after whiplash trauma.

There is limited knowledge about the possible long-term effects on jaw motor function after whiplash trauma. The primary aim was to evaluate integrated jaw and head-neck movement amplitudes during jaw function in individuals 2 years after whiplash trauma, compared to controls. The secondary aim was to evaluate changes between the acute stage and a 2-year follow-up in terms of jaw and head-neck movement amplitudes during jaw function. This study included 28 cases exposed to a whiplash trauma 2 years earlier (13 women) and 28 controls (13 women) without previous neck trauma. Head and jaw movement amplitudes were recorded during maximal jaw opening-closing movements using an optoelectronic 3D recording system. For a subpopulation of 12 cases and 15 controls, recordings had also been performed in the acute stage after the whiplash trauma. Jaw and head movement amplitudes were analysed using linear regression with group and sex as independent variables. The subpopulation longitudinal analysis was adjusted for movement amplitudes at baseline. Jaw movement amplitudes were significantly associated with group (coefficient: -0.359: 95% CI: -10.70 to -1.93, p = .006) with smaller amplitudes of jaw movements for whiplash cases. Head movement amplitudes were not associated with group (coefficient: -0.051, 95% CI: -4.81 to 3.20, p = .687). In the longitudinal analysis, both jaw and head movement amplitudes showed significant associations between baseline and the 2-year follow-up. The present findings indicate that the effects on jaw function in terms of jaw opening capacity in the acute stage after whiplash trauma do not spontaneously recover.

La recherche préhistorique du Pléistocène et de l’Holocène en Amérique du Sud : une perspective techno-fonctionnelle

The field of prehistoric research in South America has been shaped by various schools of thought. Historically, the French School probably focused more on the most ancient periods. This school has applied rigorous excavation methods, including spatial studies, 3D recording of archaeological remains, and technological analyses of lithic artifacts. In the past two decades, a new school of thought — functional technology — has emerged, offering a fresh perspective in prehistoric research. This article aims to undertake an historical review of academic contributions on this theme, reflect on the impact of this school as a methodological cornerstone for lithic studies in South America, and propose scientific guidelines for current and future research.

Integration of photogrammetry and laser scanning for enhancing scan-to-HBIM modeling of Al Ula heritage site

The study highlights the significance of combining imaging and laser scanning techniques to enrich point clouds used for reliable documentation and Heritage Building Information Modeling (HBIM). The fusion-based approach was used to document Al Ula Heritage site in Saudi Arabia, a UNESCO World Heritage Site with well-preserved tombs from the first century BC. The HBIM parametric modeling process requires a detailed survey to collect all geometric data. Although terrestrial laser scanners (TLS) are an efficient tool for 3D recording of heritage scenes in a short period of time, the data resolution is insufficient for identifying and evaluating the spatial distribution of surface weathering forms. Furthermore, combining scans collected at different times may pose difficulties in recording the texture. These issues have an impact on the subsequent 3D modeling phase as well as the efficiency of interpreting and tracing surface features in the Scan-to-BIM process. The proposed workflow using imagery data to enhance both the geometry and coloring of laser point clouds. In addition to texture mapping, the high-resolution imagery is used to densify the laser data using dense image matching, allowing for a clear reading of the surface features, and serving as a useful tool to identify the type, extent, and severity of façade damage. TLS and imagery data were collected separately, with images taken at the best time and location for realistically recording of surface details. Finally, the captured images are orthorectified by TLS geometric information and used for HBIM texturing to provide realistic decay mapping. The results showed that the combination of TLS and photogrammetry allowed for the efficient collection of 3D data, which improved tracing and digitizing HBIM with complete mapping information. The research findings will be greatly useful in the management and planning of historic building conservation and restoration projects.

THE FIRST ATTEMPT FOR STANDARDISATION IN 3D DIGITISATION. THE EU STUDY ON QUALITY IN 3D DIGITISATION OF TANGIBLE CULTURAL HERITAGE

Abstract. This paper focuses on the exceptional results of the EU Study (Commission et al., 2022) to map the parameters, formats, standards, benchmarks and methodologies relating to the 3D digitisation of tangible cultural heritage (CH). The overall objective of our paper is to further the quality of the 3D digitisation process by enabling cultural heritage professionals, institutions, content developers, stakeholders and academics to define and produce high-quality digitisation standards and sustainable conservation models for the preservation, documentation, understanding, and accessibility of tangible cultural heritage assets. The aim is to achieve high quality results during the 2D and 3D recording process of CH tangible assets. This work identifies for the first time in this domain, key parameters of the digitisation process, estimated the relative complexity and how it is linked to technology, its impact on quality and its various factors. It also presents standards and formats used for 3D digitisation, including data types, data formats and metadata schemas for 3D structures within a holistic documentation approach. Finally, this work presents and describes all the features and parameters of the complexity and quality that influence the methodology and infrastructure to be used for high quality results regarding digital cultural heritage. These complexity and quality factors are illustrated in the form of radial charts with the corresponding relevant information at the end of the paper.

Multimodality imaging (3D Echocardiography, 3D printing and confocal microscopy) for paravalvular leak visualization

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): National Center for Research and Development as part of the strategic program "Prevention and treatment of civilization diseases" Strategmed II Project "Integrated paravalvular leak closure system" -acronym VALE, Paravalvular leak (PVL) may occur in 15% of patients undergoing surgical mitral valve replacement. Visualization of PVL channels may be challenging due to its proximity to the prosthetic valve and complex anatomy. The main aim of this study was to use a confocal microscope to measure PVL channel dimensions. With 3D-TEE (Philips Epiq) an anteromedial mitral defect was visualized. Qlab Station was used to export the 3D recording of the PVL with surrounding tissue in cartesian DICOM format. Next Slicer, a free open-source software, was used for segmentation and preparation of a STL (stereolithography) file. The PVL model was printed with Starsys Object 30 printer using Med620 material. PVL diameters were measured both after MPR of source echocardiographic data and in the printed model with a confocal microscope. The same results were obtained. Thus, the possibility of using the standard 3D-TEE and open source software for preparation of 3D models of anatomically complex mitral PVLs was confirmed. In addition, a confocal microscope can be used to measure PVL dimensions of models printed from echocardiographic data. Background Paravalvular leak (PVL) may occur in almost 15% of patients undergoing surgical mitral valve replacement. This complication can cause patient’s significant deterioration (congestive heart failure and hemolysis). Visualization of PVL channel may be challenging due to its proximity to prosthetic valve (shadowing) and complex and tortuos anatomy. 3D imaging from CT and echocardiography is essential for assessment of PVLs. 3D-TEE-based 3D-printing might be useful in preprocedural planning of PVL closure for the optimization of transcatether procedures. As feasibility of such printing is proven, now we are looking for best techniques to measure PVL channels. Purpose Confocal microscope appliance to measure PVL chanel dimensions Methods In case of a significant PVL around a mitral prosthetic valve is presented. In 3DTEE (Philips Epiq) anteromedial defects were visualized (surgical view). Qlab Station was used to export the 3D recording of PVLs with surrounding tissue in cartesian DICOM format. Next Slicer, a free open-source software, was used for segmentation and preparation of a STL (stereolithography) file. The PVL model was printed with Starsys Object 30 printer using Med620 material. PVL diameters were measured in MPR from 3D Echocardiography and after analysis in confocal microscope at printed model. Measurements were the same 10/5 mm. Results Confocal microscope can be used to measure PVL dimensions from printed models from echocardiography. Figure1 MPR 2D measurements of PVLs, and printed model of PVL. Figure 2 Measurements form confocal microscope. Conclusion(s) Proof of concept study confirms feasibility of using multimodality imagine for measurements of PVL. Further studies to assess clinical applicability of the presented methodology are ongoing.

Dual-modulation of micro-photoluminescence in rare-earth-doped crystals by femtosecond laser irradiation for 5D optical data storage

In transparent dielectric materials, the property modulation induced by femtosecond laser irradiation (FLI) holds great promise for optical storage due to the advantages of high resolution, material flexibility and 3D recording capability. However, the benefits are often mitigated by its incapability of information multiplexing or stringent requirements on fabrication conditions. Here, based on the dual-modulation of micro-photoluminescence (μ-PL) in Pr:YLF crystals by applying FLI, a novel strategy for optical data storage (ODS) is proposed and experimentally demonstrated. Multiple laser parameters within broad ranges can be used to fine-tune the μ-PL emission bands of Pr3+ ions to create storage voxels, which makes the information recording more feasible and flexible from a perspective of practical application. Remarkably, the dual modulation of spectral features at around 638 and 641 nm, in combination with the innovative design of voxels, make it possible to realize both emission-intensity-multiplexing and emission-wavelength-multiplexing, meeting the requirements for large memory capacity and high encryption of new generation ODS. Furthermore, the spatially selective control of μ-PL signals through secondary FLI allows for rewriting and erasure of the encoded information. This work opens new opportunities for rare-earth-doped materials in the applications of multidimensional rewritable/erasable high-density optical data storage and optical information encryption.

Underwater 3D Scanning System for Cultural Heritage Documentation

Three-dimensional capturing of underwater archeological sites or sunken shipwrecks can support important documentation purposes. In this study, a novel 3D scanning system based on structured illumination is introduced, which supports cultural heritage documentation and measurement tasks in underwater environments. The newly developed system consists of two monochrome measurement cameras, a projection unit that produces aperiodic sinusoidal fringe patterns, two flashlights, a color camera, an inertial measurement unit (IMU), and an electronic control box. The opportunities and limitations of the measurement principles of the 3D scanning system are discussed and compared to other 3D recording methods such as laser scanning, ultrasound, and photogrammetry, in the context of underwater applications. Some possible operational scenarios concerning cultural heritage documentation are introduced and discussed. A report on application activities in water basins and offshore environments including measurement examples and results of the accuracy measurements is given. The study shows that the new 3D scanning system can be used for both the topographic documentation of underwater sites and to generate detailed true-scale 3D models including the texture and color information of objects that must remain under water.

Mobile Phone Imaging Point Cloud Modelling for 3D Recording and Measurement of Small Scenes of Suspected Fossil Outcrops Found in the Field

Mobile Phone Imaging Point Cloud Modelling for 3D Recording and Measurement of Small Scenes of Suspected Fossil Outcrops Found in the Field

Using AI Motion Capture Systems to Capture Race Walking Technology at a Race Scene: A Comparative Experiment

Background: This study tested the reliability of the 3D coordinates of human joint points obtained by using an AI motion capture system at a race walking scene. Methods: Using a direct linear transformation (DLT) 3D video recording method, 15 race walking athletes were photographed. We compared the average values, standard deviations, and 95% confidence intervals of the multiple correlation coefficients and differences in the 3D coordinate–time curve of the human joint points that were automatically parsed by the AI motion capture system with those that were manually parsed. Results: Except for the left shoulder y coordinates, left hip y and z coordinates, and left toe tip z coordinates, the multiple correlation coefficients between the curve obtained via the automatic analysis and the average curve obtained via the manual analysis of the other coordinates were greater than 0.90, while the difference between the curve obtained via the automatic analysis and the curve obtained via the manual analysis of the left hand, the left wrist, the left hip, and the left toe was less than 0.025 m. Conclusion: The 3D coordinates of the human joint points obtained via the AI motion capture system were highly similar to the average value of the 3D coordinates obtained via the manual analysis, supporting the use of the AI motion capture system as a highly reliable means to capture the technical motion of race walking in the race walking competition context.

7 Recent research on Greek architecture: 2012–2022

The discipline of Greek architecture has been changing rapidly since the time of a major review published in 2011. The current study examines research published since 2012 about the prehistoric through to the Hellenistic eras in mainland Greece and the Aegean, along with the expansion of Greek architectural systems throughout the Mediterranean and Black Sea in the first millennium BC. A narrative discussing close to 300 works from recent years is bolstered by a quantitative analysis of the subjects treated in nearly 1,000 studies from the previous decade. Traditional foci of the discipline, such as palaces and sanctuaries, are being approached in new and methodologically sophisticated manners. A notable rise in the scrutiny of material remains suggests diverse new interests in planning and construction, from the scale of an individual architectural member up to a territorial defence network. The integration of recent digital and scientific methods has been remarkable, including widespread adoption of 3D recording and modelling, remote sensing, and compositional analysis. Certain architectural types – in particular fortifications, harbours, and urban planning – have received a great deal more attention than in past decades.

Harbourview: An Irish-Welsh networking initiative

Historic harbours, as infrastructural elements, are neither buildings nor monuments thus typically fall between the remits of heritage designation. Yet they are critical to reading the human occupation of islands historically. Inevitably these routes and points of embarkation and disembarkation were pathways not just for goods, but also for knowledge, beliefs, and broader cultural understanding. The rising sea levels and increased storm activity generated by climate change are endangering the survival of this important coastal heritage on both sides of the Irish Sea. Harbourview, a research alliance between Cardiff University (Wales) and University College Dublin (Ireland) funded by the ESRC and the IRC, is a networking project which aimed to establish new dialogues on the significance of these harbours and the means by which they can be documented and appropriately managed. Through a series of seminars, community workshops and a final symposium, researchers, relevant stakeholders in local and national governments, and local communities in Ireland and Wales participated in activities and discussions on how best to address this compelling coastal heritage. The Harbourview project established the potential of community documentation using newly accessible methods of 3D recording and visualization, and, in tandem with the seminar and final symposium, clarified the critical issues in achieving a comprehensive documentation of this invaluable heritage.

The 3D recording of the so-called Spreti sarcophagus in the Basilica of San Vitale (Ravenna, Italy)

Abstract This article presents our experience in digitizing a Late Antique sarcophagus using and combining two different recording methods: Structure from Motion (SfM) and Structured Light Scanning. Due to preservation purposes, it was necessary to obtain a reliable 3D digital reproduction of the artifact to perform observations, measurements, and produce graphic layouts for possible forthcoming restorations. The employment of two recording techniques (hardware + software) was necessary to overcome some loss of data that were registered during the acquisition phase. Each method showed some failure in detecting or processing portions of the object surface, mainly due to the mechanical properties of the material (marble) on which the sarcophagus is made.

3D Engineering of Orbital Angular Momentum Beams via Liquid‐Crystal Geometric Phase

AbstractOrbital angular momentum (OAM) provides a novel degree of freedom for light, deeply inspiring versatile light‐matter interactions and large‐density multiplexing computing. Recently, multimode and multichannel control of OAM beams have aroused extensive curiosity, whereas their flexible engineering in 3D space still remains challenging. Here, a new type of liquid‐crystal geometric phase optical elements is demonstrated to achieve on‐demand 3D tailoring of OAM beams. Via integrating binary and continuous phase patterns into photo‐aligned liquid crystals, customized 3D lattices of identical or propagation‐variant OAM beams are generated in an electrically tunable broadband manner. By altering the incident spin, these volumetric OAM beams can be switched among different states on the higher‐order Poincaré sphere. This work demonstrates a practical approach toward efficient OAM harnessing with large channel capacity and high spatial mode diversity, holding great potential for 3D optical manipulation, recording, and microscopy.

The DISAPALE Project: A New Digital Repository of Lithic and Bone Artefacts

ABSTRACT As for every aspect in our daily lives, in the past two decades a digital turn has stormed Archaeology. More specifically, in the field of Palaeolithic research, 3D recording methods are currently starting to become an established standard in the documentation, study and analysis of lithic artefacts. Once made available to public, the DISAPALE project will represent one of the largest 3D-models repository of lithic artefact: after introducing the project, its goals and main characteristics, the paper first contextualizes the specific nature of the blank material in relation to the 3D recording techniques, and then presents a significant example of the workflow that has been implemented during the DISAPALE project and a comparison between 3D models of three objects realized with two different methods, briefly discussing their relative pros and cons.

Mitral paravalvular leak 3D printing from 3D-transesophageal echocardiography - proof of concept

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Science and Higher Education Background Paravalvular leak (PVL) may occur in almost 15% of patients undergoing surgical mitral valve replacement. This complication can cause congestive heart failure and hemolysis. Multimodal imaging including computed tomography (MSCT) and 3D-transesophageal echocardiography (3D-TEE) is essential for assessment of PVLs. 3D-TEE-based 3D-printing might be useful in preprocedural planning of PVL closure for the optimization of transcatether procedures. In contrast to 3D-printing based on MSCT, use of 3D-TEE for segmentation and printing is not standardized. Purpose A proof of concept study to evaluate 3D printing of mitral PVLs using 3D-TEE. Methods A case of a 64-year-old woman with 2 clinically significant PVLs around a mitral prosthetic valve is presented. In 3D-TEE (Philips Epiq) anteromedial defects were visualized (surgical view). Qlab Station was used to export the 3D recording of PVLs with surrounding tissue in cartesian DICOM format. Next Slicer, a free open-source software, was used for segmentation and preparation of a STL (stereolithography) file. The PVL model was printed with Starsys Objet 30 printer using Med620 material. Diameters PVLs were the same in 3D Echocardiography and 3D printed model (12mm and 9mm). Results Printed PVL model and corresponding 3D-TEE image are shown in Figure 1 and Figure 2, respectively. Conclusion(s) Proof of concept study confirms feasibility of using standard 3D-TEE and open source software for preparation of 3D models of anatomically complex mitral PVLs. Further studies to assess cost-effectiveness and clinical applicability of the presented methodology are ongoing. Abstract Figure 1. Abstract Figure 2.

Towards Semantic Photogrammetry: Generating Semantically Rich Point Clouds from Architectural Close-Range Photogrammetry.

Developments in the field of artificial intelligence have made great strides in the field of automatic semantic segmentation, both in the 2D (image) and 3D spaces. Within the context of 3D recording technology it has also seen application in several areas, most notably in creating semantically rich point clouds which is usually performed manually. In this paper, we propose the introduction of deep learning-based semantic image segmentation into the photogrammetric 3D reconstruction and classification workflow. The main objective is to be able to introduce semantic classification at the beginning of the classical photogrammetric workflow in order to automatically create classified dense point clouds by the end of the said workflow. In this regard, automatic image masking depending on pre-determined classes were performed using a previously trained neural network. The image masks were then employed during dense image matching in order to constraint the process into the respective classes, thus automatically creating semantically classified point clouds as the final output. Results show that the developed method is promising, with automation of the whole process feasible from input (images) to output (labelled point clouds). Quantitative assessment gave good results for specific classes e.g., building facades and windows, with IoU scores of 0.79 and 0.77 respectively.

Emerging materiality through dynamic digital conservation

In the neuralgic field of restoration of delicate sculptural artworks, the contribution of high-precision, contactless three-dimensional (3D) recording in the documentation of their current condition and their further digital investigation are proven valuable. However, the incredible possibilities of the digital sphere oppose the limitations of the matter, raising case-specific ethical and practical issues that highlight the complexity of the restoration process. The nature of the construction material(s) of any cultural artifact determines not only their aging and deterioration ratio in relation to their exposure to environmental conditions but also the ethically acceptable and practically feasible degree of intervention for their conservation. So far, the digital conservation approaches concern artifacts made of rigid materials, such as ceramic and stone. Their very nature determines their conservation treatment in the real world and dictates their digital approach, which orbits around the repositioning of their detached fragments, the supplementation or reconstruction of their lost parts, the design of support structures for display or storage, etc.The singularity of the ‘Xenophanes’ figurine lies in its strong plasticity and the malleable contemporary construction materials (wax and plasticine), which require specialized conservation interventions to be preserved. Over time, the inclination of the figurine has changed significantly, posing stability and deformation issues; its head and stick are detached, and both hands are lost. The timeline of the weathering of this particular artwork is documented at two points in time, in 2005 and 1994.This paper presents the first stage of an ongoing investigation. It includes the documentation of the artworks with both active and passive recording methods, their post-processing methodology offering the opportunity to combine their strengths and integrate them in the resulting 3D model. This final model was subsequently used to accomplish the digital restoration of the figurine to its earlier state(s). The workflow of 3D keyframe animation facilitated the restoration of our non-rigid figurine in digital time. The complexity of the decision-making process for the digital restoration of flexible artworks is highlighted by a series of ethical and applied considerations that arise during the procedure, along with the desire for a digital 3D object that corresponds to the singularity of the authentic artwork in order to evaluate the restoration possibility of the latter. The nature and needs of the figurine studied here allow a dynamic digital post-processing conservation approach that moves beyond reassembly, and within the limits of the tolerances of its construction materials for its reformation, in order to study the restoration steps to earlier states as well as the simulation of a possible physical approach to the object. In such an approach, where the materiality and plasticity of the authentic artifact are interwoven with the protocol for the digital conservation approach, the knowledge and experience of an Information and Communication Technology (ICT) skilled conservator was instrumental.