3d modelling of archaeological small finds by a low-cost range camera. Methodology and first results

The production of reliable documentation of small finds is a crucial process during archaeological excavations. Range cameras can be a valid alternative to traditional illustration methods: they are veritable 3D scanners able to easily collect the 3D geometry (shape and dimensions in metric units) of an object/scene practically in real-time. This work investigates precisely the potentialities of a promising low-cost range camera, the Structure SensorTM by Occipital, for rapid modelling archaeological objects. The accuracy assessment was thus performed by comparing the 3D model of a Cipriot-Phoenician globular jug captured by this device with the 3D model of the same object obtained through photogrammetry. In general, the performed analysis shows that Structure Sensor is capable to acquire the 3D geometry of a small object with an accuracy comparable at millimeter level to that obtainable with the photogrammetric method, even though the finer details are not always correctly modelled. The texture reconstruction is instead less accurate. In the end, it can be concluded that the range camera used for this work, due to its low-cost and flexibility, is a suitable tool for the rapid documentation of archaeological small finds, especially when not expert users are involved

3D shape measurement techniques for human body reconstruction

In this work the performances of three different techniques for 3D scanning have been investigated. In particular two commercial tools (smartphone camera and iPad Pro LiDAR) and a structured light scanner (Go!SCAN 50) have been used for the analysis. First of all, two different subjects have been scanned with the three different techniques and the obtained 3D model were analysed in order to evaluate the respective reconstruction accuracy. A case study involving a child was then considered, with the main aim of providing useful information on performances of scanning techniques for clinical applications, where boundary conditions are often challenging (i.e., non-collaborative patient). Finally, a full procedure for the 3D reconstruction of a human shape is proposed, in order to setup a helpful workflow for clinical applications.</p

Creation of a Virtual Atlas of Neuroanatomy and Neurosurgical Techniques Using 3D Scanning Techniques

Neuroanatomy is one of the most challenging and fascinating topics within the human anatomy, due to the complexity and interconnection of the entire nervous system. The gold standard for learning neurosurgical anatomy is cadaveric dissections. Nevertheless, it has a high cost (needs of a laboratory, acquisition of cadavers, and fixation), is time-consuming, and is limited by sociocultural restrictions. Due to these disadvantages, other tools have been investigated to improve neuroanatomy learning. Three-dimensional modalities have gradually begun to supplement traditional 2-dimensional representations of dissections and illustrations. Volumetric models (VM) are the new frontier for neurosurgical education and training. Different workflows have been described to create these VMs -photogrammetry (PGM) and structured light scanning (SLS). In this study, we aimed to describe and use the currently available 3D scanning techniques to create a virtual atlas of neurosurgical anatomy. Dissections on post-mortem human heads and brains were performed at the skull base laboratories of Stanford University - NeuroTraIn Center and the University of California, San Francisco - SBCVL (skull base and cerebrovascular laboratory). Then VMs were created following either SLS or PGM workflow. Fiber tract reconstructions were also generated from DICOM using DSI-studio and incorporated into VMs from dissections. Moreover, common creative license materials models were used to simplify the understanding of the specific anatomical region. Both methods yielded VMs with suitable clarity and structural integrity for anatomical education, surgical illustration, and procedural simulation. We described the roadmap of SLS and PGM for creating volumetric models, including the required equipment and software. We have also provided step-by-step procedures on how users can post-processing and refine these images according to their specifications. The VMs generated were used for several publications, to describe the step-by-step of a specific neurosurgical approach and to enhance the understanding of an anatomical region and its function. These models were used in neuroanatomical education and research (workshops and publications). VMs offer a new, immersive, and innovative way to accurately visualize neuroanatomy. Given the straightforward workflow, the presently described techniques may serve as a reference point for an entirely new way of capturing and depicting neuroanatomy and offer new opportunities for the application of VMs in education, simulation, and surgical planning. The virtual atlas, divided into specific areas concerning different neurosurgical approaches (such as skull base, cortex and fiber tracts, and spine operative anatomy), will increase the viewer's understanding of neurosurgical anatomy. The described atlas is the first surgical collection of VMs from cadaveric dissections available in the medical field and could be a used as reference for future creation of analogous collection in the different medical subspeciality.La neuroanatomia è, grazie alle intricate connessioni che caratterizzano il sistema nervoso e alla sua affascinante complessità, una delle discipline più stimolanti della anatomia umana. Nonostante il gold standard per l’apprendimento dell’anatomia neurochirurgica sia ancora rappresentato dalle dissezioni cadaveriche, l’accessibilità a queste ultime rimane limitata, a causa della loro dispendiosità in termini di tempo e costi (necessità di un laboratorio, acquisizione di cadaveri e fissazione), e alle restrizioni socioculturali per la donazione di cadaveri. Al fine di far fronte a questi impedimenti, e con lo scopo di garantire su larga scala l’apprendimento tridimensionale della neuroanatomia, nel corso degli anni sono stati sviluppati nuovi strumenti e tecnologie. Le tradizionali rappresentazioni anatomiche bidimensionali sono state gradualmente sostituite dalle modalità 3-dimensionali (3D) – foto e video. Tra questi ultimi, i modelli volumetrici (VM) rappresentano la nuova frontiera per l'istruzione e la formazione neurochirurgica. Diversi metodi per creare questi VM sono stati descritti, tra cui la fotogrammetria (PGM) e la scansione a luce strutturata (SLS). Questo studio descrive l’utilizzo delle diverse tecniche di scansione 3D grazie alle quali è stato creato un atlante virtuale di anatomia neurochirurgica. Le dissezioni su teste e cervelli post-mortem sono state eseguite presso i laboratori di base cranica di Stanford University -NeuroTraIn Center e dell'Università della California, San Francisco - SBCVL. I VM dalle dissezioni sono stati creati seguendo i metodi di SLS e/o PGM. Modelli di fibra bianca sono stati generate utilizzando DICOM con il software DSI-studio e incorporati ai VM di dissezioni anatomiche. Inoltre, sono stati utilizzati VM tratti da common creative license material (materiale con licenze creative comuni) al fine di semplificare la comprensione di alcune regioni anatomiche. I VM generati con entrambi i metodi sono risultati adeguati, sia in termini di chiarezza che di integrità strutturale, per l’educazione anatomica, l’illustrazione medica e la simulazione chirurgica. Nel nostro lavoro sono stati esaustivamente descritti tutti gli step necessari, di entrambe le tecniche (SLS e PGM), per la creazione di VM, compresi le apparecchiature e i software utilizzati. Sono state inoltre descritte le tecniche di post-elaborazione e perfezionamento dei VM da poter utilizzare in base alle necessità richieste. I VM generati durante la realizzazione del nostro lavoro sono stati utilizzati per molteplici pubblicazioni, nella descrizione step-by-step di uno specifico approccio neurochirurgico o per migliorare la comprensione di una regione anatomica e della sua funzione. Questi modelli sono stati utilizzati a scopo didattico per la formazione neuroanatomica di studenti di medicina, specializzandi e giovani neurochirurghi. I VM offrono un modo nuovo, coinvolgente e innovativo con cui poter raggiungere un’accurata conoscenza tridimensionale della neuroanatomia. La metodologia delle due tecniche descritte può servire come punto di riferimento per un nuovo modo di acquisizione e rappresentazione della neuroanatomia, ed offrire nuove opportunità di utilizzo dei VM nella formazione didattica, nella simulazione e nella pianificazione chirurgica. L'atlante virtuale qui descritto, suddiviso in aree specifiche relative a diversi approcci neurochirurgici, aumenterà la comprensione dell'anatomia neurochirurgica da parte dello spettatore. Questa è la prima raccolta chirurgica di VM da dissezioni anatomiche disponibile in ambito medico e potrebbe essere utilizzato come riferimento per la futura creazione di analoga raccolta nelle diverse sotto specialità mediche

Stereo uparivanje iz video isječka

This paper proposes a novel method for stereo matching which is based on combination of active and passive stereo 3D reconstruction approaches. A laser line is used to scan the reconstructed scene and a stereo camera pair is used for the image acquisition. Each image pixel is scanned at a specific scan time so that the intensity time patterns of the correspondent pixels are highly correlated. This yield in highly confident and accurate disparity map calculation and also allows the reconstruction of poorly textured as well as the extremely textured surface which are very hard to deal with using the conventional passive stereo approaches. The occluded regions are also detected successfully. This method is not computationally intensive and can be used for turning the smartphone into the practical 3D scanner as presented in this work.Ovim radom predstavljena je nova metoda stereo uparivanja temeljena na kombinaciji aktivnog i pasivnog stereo pristupa. Rekonstruirana scena skenirana je laserskom linijom, dok se par stereo kamera koristi za akviziciju video isječka. Svaki slikovni element rekonstruirane scene skeniran je laserskom linijom u određenom trenutku stoga su profili intenziteta svjetline u vremenskoj domeni izrazito korelirani za slikovne elemente lijeve i desne kamere koji odgovaraju istom slikovnom element rekonstruirane scene. Stoga je rezultat predstavljene metode određivanje stereo parova slikovnih elemenata s visokom pouzdanošću. Nadalje, predstavljena metoda omogućuje rekonstruiranje izrazito slabo odnosno izrazito intenzivno teksturiranih scena što je često veoma teško postići korištenjem konvencionalnih metoda stereo 3D rekonstrukcije. Metoda je jednostavna te ju je moguće implementirati na sustavima ograničenih računarskih resursa, stoga je iznimno pogodna za primjenu na mobilnim platformama primjerice pametnim telefonima

3D MODELS FOR ALL: LOW-COST ACQUISITION THROUGH MOBILE DEVICES IN COMPARISON WITH IMAGE BASED TECHNIQUES. POTENTIALITIES AND WEAKNESSES IN CULTURAL HERITAGE DOMAIN

Nowadays, 3D digital imaging proposes effective solutions for preserving the expression of human creativity across the centuries, as well as is a great tool to guarantee global dissemination of knowledge and wide access to these invaluable resources of the past. Nevertheless, in several cases, a massive digitalisation of cultural heritage items (from the archaeological site up to the monument and museum collections) could be unworkable due to the still high costs in terms of equipment and human resources: 3D acquisition technologies and the need of skilled team within cultural institutions. Therefore, it is necessary to explore new possibilities offered by growing technologies: the lower costs of these technologies as well as their attractive visual quality constitute a challenge for researchers. Besides these possibilities, it is also important to consider how information is spread through graphic representation of knowledge. The focus of this study is to explore the potentialities and weaknesses of a newly released low cost device in the cultural heritage domain, trying to understand its effective usability in museum collections. The aim of the research is to test their usability, critically analysing the final outcomes of this entry level technology in relation to the other better assessed low cost technologies for 3D scanning, such as Structure from Motion (SfM) techniques (also produced by the same device) combined with dataset generated by a professional digital camera. The final outcomes were compared in terms of quality definition, time processing and file size. The specimens of the collections of the Civic Museum Castello Ursino in Catania have been chosen as the site of experimentation

3D-Scanner for Hochschule Esslingen

The work was done for Hochschule Esslingen and its main purpose was to provide the school with a comprehensive explanation of different 3-dimensional scanning systems and their functions. It was also deemed necessary for it to provide reviews of dimensional scanning equipment on the market with a detailed review of at least one system, as well as provide arguments to why the School should obtain the technology as a part of its process chain. The research was done using the internet to search for different sources such as technology reviews, news articles and books sources as well as blogs and forums where enthusiasts talk about the subject matter. Finally, a free photogrammetry app was downloaded from the app store for practical review purposes. The result of the research is a broad review of the current technology and what are considered the most eligible commercial scanners through different criteria’s such as price, ease of use and accuracy, with some speculation of the future of the technology and its benefits