Proposal of Radiometric Correction for the In-Situ Modelling of Polychrome Religious Carvings

The authors present a vision based augmented reality system called Happy Measure to facilitate the measurement, 3D modeling, and visualization of furniture and other objects using a smartphone or mobile device equipped with a camera. They also study the concomitant interaction metaphors that enable interactive 3D model capture and manipulation in augmented environments. The proposed system allows for interactive measurement of an object’s size and the creation of primitive based 3D models from a single photograph. The appearance of the furniture (color textured model) is captured by the system using the underlying (or multiple) images taken by the user. This allows the user to capture textured 3D models of furniture or other objects and manipulate them virtually for visualization purposes. The authors compare two interaction metaphors used to capture 3D textured models of object to ensure easy interaction while still obtaining accurate measurements in a user test. Results suggest that one is superior in terms of measurement accuracy and also subjective user experience as it allows for continuous touch interaction on the whole screen. Virtually placing a modeled object in another location is another aspect of the presented system and the authors explore a novel interaction paradigm to perform this task along with initial user tests.

Cadaveric dissections, which are considered the most realistic model to study neuroanatomy, are expensive and not readily available in all centers. Given the surge of technological advances, incorporation of three-dimensional (3D) scanning technologies and 3D models has gained popularity, both in the educational and clinical settings. We present our institutional experience in creating high-fidelity neuroanatomical 3D models using three 3D scanning techniques: structured light 3D scanning, "manual" photogrammetry with a single DSLR camera, and "automatic" photogrammetry using a scanner equipped with five vertically arranged DSLR cameras and an automatic turntable within a square box. A survey study was conducted with 20 neurosurgical residents to assess the quality of the three resulting 3D models. In the study, "manual" photogrammetry was determined to be the most cost-effective technique, while "automatic" photogrammetry was the most time-effective and user-friendly technique. The best visual quality was obtained using "manual" photogrammetry, as determined from survey results of 20 neurosurgical residents. While structured light 3D scanning had the lowest quality of resolution of the texture map, this technique was the most accurate to use for determining measurements, with a fixed accuracy of 0.05 mm. Overall, "manual" photogrammetry can allow for the most detailed 3D models and is the most cost-effective strategy, while structured light 3D scanning is most suitable for obtaining clinically relevant measurements given the high degree of structural accuracy. Alternatively, "automatic" photogrammetry can serve as a hybrid between obtaining relatively high-quality models in a time-effective and user-friendly manner.

Facial asymmetry presents a significant challenge for health practitioners, including physicians, dentists, and physical therapists. Manual measurements often lack the precision needed for accurate assessments, highlighting the appeal of imaging technologies like structured light scanners and photogrammetric systems. However, high-end commercial systems remain cost prohibitive, especially for public health services in developing countries. This study aims to evaluate cell-phone-based photogrammetric methods for generating 3D facial models to detect facial asymmetries. For this purpose, 15 patients had their faces scanned with the ACADEMIA 50 3D scanner, as well as with cell phone images and videos using photogrammetry and videogrammetry, resulting in 3D facial models. Each 3D model (coming from a 3D scanner, photogrammetry, and videogrammetry) was half-mirrored to analyze dissimilarities between the two ideally symmetric face sides using Hausdorff distances between the two half-meshes. These distances were statistically analyzed through various measures and hypothesis tests. The results indicate that, in most cases, both photogrammetric and videogrammetric approaches are as reliable as 3D scanning for detecting facial asymmetries. The benefits and limitations of using images, videos, and 3D scanning are also presented.

This study aimed to create 3D-printed insoles for flat-footed senior men using 3D systems. 3D systems are product-manufacturing systems that use 3-dimensional technologies like 3D scanning, 3D modeling, and 3D printing. This study used a 3D scanner (NexScan2), 3D CAD programs including Rapidform, AutoCAD, SolidWorks, Nauta+ compiling program, and a 3D printer. In order to create insoles for flat-footed senior men, we analyzed horizontal sections of 3D foot scans We selected 20 flatfooted and 20 normal-footed subjects. To make the 3D insole models, we sliced nine lines on the surface of the subjects` 3D foot scans, and plotted 144 points on the lines. We calculated the average of these 3D coordinates, then located this average within the 3D space of the AutoCAD program and created 3D sole models using the loft surface tools of the SolidWorks program. The sole models for flat feet differed from those of normal feet in the depth of the arch at the inner sideline and the big toe line. We placed the normal-footed sole model on a flat-footed sole model, and the combination of the two models resulted in the 3D insole for flat feet. We printed the 3D modeled insole using a 3D printer. The 3D printing material was an acrylic resin similar to rubber. This made the insole model flexible and wearable. This study utilized 3D systems to create 3D insoles for flat-footed seniors and this process can be applied to manufacture other items in the fashion industry as well.

The untapped potential of 3D virtualization using high resolution scanner-based and photogrammetry technologies for bone bank digital modeling

Recently, a laser scanner has been receiving more attention as a useful tool for real-time 3D data acquisition, and various applications such as city modeling, DTM generation and 3D modeling of cultural heritage were proposed. However, robust filtering for distinguish on- and off-terrain points from point cloud 3D data collected by airborne laser scanner is still issues. In particular, filtering of point cloud 3D data collected by terrestrial laser scanner has more severe problems caused by many occlusion parts, windows, few the deepest points, wall of buildings and so on. In order to perform 3D texture modeling of cultural heritage using terrestrial laser ranging data, texture modeling method are investigated in this paper, and proposed filtering method is based on flatness within 30*30cm. Flatness area (ground surface, wall of structures, etc.) and non-flatness area (trees, bushes, etc.) is classified using measurement result of many target., and non-flatness areas are interpolated using morphological procedure. The filtering method shows very robust result, and the most remarkable point of this filtering method is its ability to obtain break-lines which give important information for 3D modeling since 3D model of historical structure are consists of flatness areas (e.g. roof, wall, pillar). Therefore, surface patch of 3D model is identified by extracting a flatness area which is surrounded by break-line, and 3D model for the patch is generated using point cloud 3D data along the frame of the patch. Furthermore, curve points for surface patch are detected from break-line, and a surface patch is generated in automatically step-by-step, texture modeling will be done with the surface patch and digital image. Therefore, automatic detection of the curve point, which is necessary for model making, is very difficult. Because, break-line includes a lot of small curve points. In this paper, we particularly watched this problem and carried out promotion of efficiency of model making by developing a solution method. With these processes, efficient 3D representation using textured model is performed without any processes. This paper presents 3D textured modeling method for historical structure using terrestrial laser ranging data and break-line by flatness evaluation, detection method of curve point using break-line.

3D technologies, including structured light scanning (SLS), microcomputed tomography (micro-CT), and 3D printing, are valuable tools for reconstructing temporal bone (TB) models with high anatomical fidelity and cost-efficiency. Operations involving TB require intimate knowledge of neuroanatomical structures-a demand that is currently met through dissection of limited cadaveric resources. We aimed to document the volumetric reconstruction of TB models using 3D technologies and quantitatively assess their anatomical fidelity. In the primary analysis, 14 anatomical characteristics of right-side TB from 10 dry skulls were measured. Each skull was 3D-scanned using SLS to generate virtual models, which were measured using mesh processing software. Metrics were analyzed using mean absolute differences and one-sample t tests with Bonferroni correction. In the secondary analysis, an individualized right-side TB specimen (TBi) was 3D-scanned using SLS and micro-CT, and 3D-printed on a stereolithography printer. Measurements of each virtual and 3D-printed model were compared to measurements of TBi. Significant differences between the physical skulls and virtual models were observed for 11 of 14 parameters (p < 0.0036), with the greatest mean difference in the length of petrous ridge (2.85 mm) and smallest difference in the diameter of stylomastoid foramen (0.67 mm). In the secondary analysis, greater mean differences were observed between TBi and virtual models than between TBi and 3D-printed models. For the first time, our study provides quantitative measurements of TB anatomy to demonstrate that 3D technologies can facilitate individualized and highly accurate reconstructions of TB, which may benefit anatomy education, clinical training, and preoperative planning.

Structured white light scanning of rabbit Achilles tendon

A three-dimensional (3D) laser scanner is one of the most well known devices when it comes to creating a 3D model of existing bridges and buildings. Most 3D scanners can pick up point clouds very accurately, which can be used to create an accurate 3D model of existing objects. One may speculate that a 3D laser scanner can also be used to pick up the status of a construction project on the job site and transform them into a 3D computer model. However, most 3D laser scanners are still expensive and they are not easy use yet especially on a congested construction site. In addition, it takes a significant amount of time to create a 3D computer model using point clouds picked up by the laser scanner. As emerging photogrammetry techniques demonstrated the use of photos instead for rapid 3D modelling, one may be wondering 1) if this technique can be used to create a 3D model of a construction site quickly, and 2) if this model is accurate enough to help project managers make some decisions. This paper presents our test demonstrating the process of creating a 3D model of an existing building using photos. It presents some challenges we faced when taking photos and creating a 3D model. This paper also presents the method we came up with to create a 3D model of the entire building without using any control points.

구두를 제작하는 기본 틀인 라스트는 3차원 형상과 관련된 정보와 기술이 총체적으로 집약된 결과물이다. 해외에서는 이미 3D 프틴팅 기술을 이용한 구두 제작이 상용화 단계에 도달하였으나, 국내에서는 아직 도입 초기 단계이다. 본 연구에서는 국내 제화산업의 경쟁력 확대를 위해, 3D 스캐닝, 3D 모델링, 3D 프린팅의 첨단 기술로 구성된 3D 제작 프로세스를 라스트 제작에 도입하였다. 이를 위해, 2010년도 SizeKorea에서 3D 스캔한 30대 남성 200명의 3D 발 형상을 사용하여, 요인분석, 군집분석을 실시하고, 3개의 발 유형을 분류한 후, 각 유형별 대표모델을 선정하였다. 대표모델들의 3D 스캐닝 형상에서 XY, YZ, XZ평면의 단면도들을 추출하고, 라스트 모델링의 스케치 단면으로 사용하였다. Solidworks CAD를 사용하여 라스트를 3D 모델링하였으며, 보급형 3D 프린터인 MakerBot Replicator2로 3D 프린팅 하였다. 본 연구 결과는 국내 제화산업에서 3D 프린팅 기술의 상용 가능성을 보여주었다. 3D 스캐닝, 3D 모델링, 3D 프린팅의 3단계 생산설계 방식은 향후 의류패션산업 전 분야에서 폭넓게 사용될 것으로 기대된다. The shoe last which is the framework for the shoemaking is intensively combined with the 3D data and technologies. International shoe companies have already commercialized 3D printing technology in producing the shoe, but domestic shoe companies are still in their early stages. This study used the 3D scanning, 3D modeling and 3D printing of the high-technology to make the shoe last. This 3D producing processes should be helpful in building competitiveness in domestic shoe industry. The 3D foot scanning data of men in 30s(n=200) were collected in SizeKorea(2010). The basic statistics, factor and cluster analysis were performed. They were categorized in 3 groups by 3D foot measurement data, and the standard models were selected in each group. The cross sections in XY, YZ and XZ planes sliced from 3D scan data of the standard model were used in the sketches of the 3D shoe last modeling. The 3D shoe last was modeled by Solidworks CAD and printed by MakerBot Replicator2; a desktop 3D printer. This research showed the potential for utilization of 3D printing technology in the domestic shoe industry. The 3D producing process; 3D scanning, 3D modeling and 3D printing is expected to utilized widely in the fashion industry within the nearest future.

Archaeology has faced increased pressure to digitise collections and make artefacts available and accessible to a wider audience. 3D imaging involves producing a 3D digital or printed model of an object or site. 3D models have the potential to augment the traditional approaches to museum engagement whilst breaking down the barriers to access, whether through providing 3D printed proxies in museums or sharing digital models online. 3D imaging has clear value in archaeology and public engagement but there is no standardisation or accessible pipelines available for achieving professional 3D imaging output. There is very little consensus in 3D modelling and worldwide, digital collections are being created with no methodological consistency. This research observed each stage necessary for producing high-quality 3D models with structured light scanning (SLS) technology. SLS was effective on a range of textures that may be encountered in archaeological scenarios, although highly reflective objects, or pale objects with black areas, may fail to be captured even with an altered strategy. In order to make the 3D model most representative of the archaeological find, it is recommended that a range of scanner settings such as brightness or shutter speed are tested on the object before committing these settings to the rest of the scans. Generalised 3D scanning pipelines are provided to inform archaeological teams on a 3D digital and printing strategy.

The widespread of recent multimedia, including various 3D model applications in different domains of areas, may lead to 3D models being stolen and attacked by hackers. Moreover, 3D models must be protected from unauthorized users and when transmitting over the internet. Nowadays the 3D model protection is a very important issue. This paper proposed a scheme that provides high protection for the textured 3D model by implementing multiple levels of security. The first level of security is achieved by encrypting the texture map based on a key generated by a 2D Logistic chaotic map. The second level of security is implemented by modifying the vertices values of the 3D mesh based on keys generated by the 3D Lorenz chaotic map. The proposed scheme was implemented on various 3D textured models varying in the number of vertices and faces. The experimental results show that the proposed scheme has a good encryption and provides high security by completely deforms the whole texture and 3D mesh of the textured 3D model into the two levels. The encryption scheme has a large key space 10135 making the scheme resists violent attacks. The Hausdorff Distance (HD) and histogram metrics are adopted to calculate the matching degree between the original and extracted model. The results show that the original and extracted model are identical through the values of HD, which are approximate to zero, and the histogram visually is similar. Index Terms— 3D textured model, encryption, 2D Logistic map, 3D Lorenz map, chaotic map

Abstract. Structured light scanners are intensively exploited in various applications such as non-destructive quality control at an assembly line, optical metrology, and cultural heritage documentation. While more than 20 companies develop commercially available structured light scanners, structured light technology accuracy has limitations for fast systems. Model surface discrepancies often present if the texture of the object has severe changes in brightness or reflective properties of its texture. The primary source of such discrepancies is errors in the stereo matching caused by complex surface texture. These errors result in ridge-like structures on the surface of the reconstructed 3D model. This paper is focused on the development of a deep neural network LineMatchGAN for error reduction in 3D models produced by a structured light scanner. We use the pix2pix model as a starting point for our research. The aim of our LineMatchGAN is a refinement of the rough optical flow A and generation of an error-free optical flow B̂. We collected a dataset (which we term ZebraScan) consisting of 500 samples to train our LineMatchGAN model. Each sample includes image sequences (Sl, Sr), ground-truth optical flow B and a ground-truth 3D model. We evaluate our LineMatchGAN on a test split of our ZebraScan dataset that includes 50 samples. The evaluation proves that our LineMatchGAN improves the stereo matching accuracy (optical flow end point error, EPE) from 0.05 pixels to 0.01 pixels.

This paper describes a similarity retrieval technique for textured 3D models. Various kinds of research have been conducted on similarity retrievals of 3D models since the late 1990's. Although most of the retrieval techniques focus on shape similarity of the 3D models, our technique allows users to retrieve and classify 3D models based on texture pattern similarity. To test our texture similarity retrieval technique, a set of a textured 3D model database was synthesized from 3D polygonal models and 2D texture images. The database was analyzed by software programs, and texture features were extracted from each 3D model. The extracted texture features were computed based on HLAC (higher order local autocorrelation) and fractal dimensions. Often, both kinds of texture features were used for analyzing 2D texture images. However, we extended the techniques to handle three dimensional volumetric data for extracting features from textured 3D models. Our experimental web-based retrieval system successfully retrieved textured 3D models with fairly acceptable recall-precision rates. This retrieval technique which is based on texture patterns can be used in conjunction with traditional shape similarity retrieval techniques, and the technique can enhance similarity retrieval performances.

BackgroundContinuous positive airway pressure (CPAP) is a common mode of respiratory support used in neonatal intensive care units. In preterm infants, nasal CPAP (nCPAP) therapy is often delivered via soft, biocompatible nasal mask suitable for long-term direct skin contact and held firmly against the face. Limited sizes of nCPAP mask contribute to mal-fitting related complications and adverse outcomes in this fragile population. We hypothesized that custom-fit nCPAP masks will improve the fit with less skin pressure and strap tension improving efficacy and reducing complications associated with nCPAP therapy in neonates.MethodsAfter IRB approval and informed consent, we evaluated several methods to develop 3D facial models to test custom 3D nCPAP masks. These methods included camera-based photogrammetry, laser scanning and structured light scanning using a Bellus3D Face Camera Pro and iPhone X running either Bellus3D FaceApp for iPhone, or Heges application. This data was used to provide accurate 3D neonatal facial models. Using CAD software nCPAP inserts were designed to be placed between proprietary nCPAP mask and the model infant’s face. The resulted 3D designed nCPAP mask was form fitted to the model face. Subsequently, nCPAP masks were connected to a ventilator to provide CPAP and calibrated pressure sensors and co-linear tension sensors were placed to measures skin pressure and nCPAP mask strap tension.ResultsPhotogrammetry and laser scanning were not suited to the neonatal face. However, structured light scanning techniques produced accurate 3D neonatal facial models. Individualized nCPAP mask inserts manufactured using 3D printed molds and silicon injection were effective at decreasing surface pressure and mask strap pressure in some cases by more than 50% compared to CPAP masks without inserts.ConclusionsWe found that readily available structured light scanning devices such as the iPhone X are a low cost, safe, rapid, and accurate tool to develop accurate models of preterm infant facial topography. Structured light scanning developed 3D nCPAP inserts applied to commercially available CPAP masks significantly reduced skin pressure and strap tension at clinically relevant CPAP pressures when utilized on model neonatal faces. This workflow maybe useful at producing individualized nCPAP masks for neonates reducing complications due to misfit.