Browsing by Subject "3D scanning"

Now showing 1 - 6 of 6
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    Automatic Anthropometric Measurement Systems from 3D Hand Scans: Accuracy of a Developed Algorithm for Large Number and Various Types of Dimensions
    (2022-08) Bhuyan, Md Arif-Ul-Anwar
    There is a research gap in using an automatic dimension extraction process to extract a large set of dimensions and different types of measurements from 3D hand scans that are developed from the physical hand. In this thesis study, an algorithm was developed, tested, and evaluated to address that gap. Twenty participants from the Human Dimensioning Lab at the University of Minnesota-Twin Cities were used. Sixty-eight Landmarks were used to extract 121 measurements (50.4% linear, 38% surface arc, and 11.6% circumference) from these scans automatically and manually in the digital medium by a measurer. Paired t-tests, mean absolute difference (MAD), and percentage of differences (diff%) were used for statistical analysis. ISO standard for maximum allowable limit is used for MAD acceptance. The automatic processing successfully measured 99.25% of all dimensions. It extracted the dimensions that the manual measuring process couldn’t measure. The automatic method extracted 87% linear, 30.4% surface-arc, and 43% circumference dimensions accurately without statistical significance. For surface-NC measurements, it measured 14 dimensions within the acceptable MAD limit. More than 50% of the dimensions that were found statistically significant had a single or double participant with a very large value that impacted the MAD value. For 60% of statistically significant dimensions, the percentage was less than 5%. For circumference measurements, 8 measurements were statistically significant and three of them have a difference percentage within 3%. Linear dimensions had statistically significant differences due to the difference in dimensions extraction procedure for breadth and depth measure between the manual and automatic measuring systems. The cause of the difference in surface-arc and circumference measurements are seemed to be similar. Thumb movement, hand posture, and scan quality were the biggest barriers to measuring these dimensions accurately. Overall, the proposed technique was performed in an acceptable form under conditions for surface-NC and circumference measurements when it is working well for linear measures. A new method is needed to validate automatic processing from the manual measuring process when they both measure from a 3D scan. Both scanning protocols, landmarking, and software need to be developed together to improve the accuracy of automatic measurements. By making the automatic process adaptive to the scan, the automatic dimension extraction process could be a game changer in 3D hand anthropometry and product design.Keywords: automatic dimension extraction, 3D hand scan, digital anthropometry, validation of measuring process, algorithm, anthroscan, manual measurement, 3D scanning
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    Posture Modification Effects Using Soft Materials Structures
    (2016-06) Lyu, Saemee
    The purpose of this study was to develop a textile component system mimicking anatomical structures that when added to a typical shapewear product will straighten and balance a person’s posture. The experimental system is referred to as the “Posture Modification System using Soft materials structures” or PMSS. Current posture modification garments fall into two categories: 1) health and rehabilitation garments focused on physical changes using rigid materials and 2) lingerie-type garments typically called shapewear that focus on achieving an ideal body using compression qualities of knit fabrics. This study explored the middle ground of designing a comfortable, wearable product that aligns posture using textile correction forces strategically placed in the garment. A biomimicry approach was used in designing the prototype using the inspiration of anatomical features of a woman’s torso to determine size and placement of textile components (PMSS) in a garment. A prototype was developed by incorporating the PMSS into a commercially available shapewear product. After a pilot test, the prototype was refined and a more comprehensive test was conducted. Twelve women participated in the study to determine effectiveness of the prototype including: 1) posture changes, 2) posture correction force, and 3) wearer acceptability. Participants were scanned three times; while wearing the prototype, wearing a typical shapewear product, and in their own underwear. Posture differences in wear conditions were analyzed. Posture correction forces of the textile materials were measured using standard fabric tests. Participants completed questionnaires on wearer acceptability. Results included: 1) body angle assessment indicated that wearing the prototype affected posture including more balanced shoulders, aligned lateral center of gravity, and straighter spine, 2) textile characteristics of the PMSS incorporated into a shapewear compression garment contribute to a more erect and balanced posture, and 3) participants were more satisfied with posture and body shape when wearing the prototype then when wearing the shapewear garment. This study indicates that the inherent properties of textiles (compression and tensile force from stretch) can be manipulated in a garment in various ways to modify posture.
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    Reconstructing Past Craft Networks: A Case Study using 3D scans of Late Bronze Age Swords to reconstruct Specialized Craft Networks
    (2016-05) Golubiewski-Davis, Kristina
    As the collection of 3d data proliferates in the archaeological community, new methods integrating analysis of those data must also be developed. This dissertation project approaches the problem of observing social networks by examining decisions made by specialized craft workers: specifically, Late Bronze Age smiths (~1200-800BC). The data examined include shape data collected from 3D scans of bronze swords. These data were used to group the blades using cluster analysis based on different aspects of the swords including blade profile, hilt profile, and various decorative shape data. Those clusters create links between the swords which were then used to examine the network of bronze smiths. This project is a case study of how one might go about studying the way individuals with specialized knowledge were connected in the past by studying the results of that knowledge expressed through tangible differences between artifacts.
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    A Simple Photogrammetry Rig for the Reliable Creation of 3D Artifact Models in the Field: Lithic Examples from the Early Upper Paleolithic Sequence of Les Cottés (France)
    (2015-06-01) Porter, Samantha T; Roussel, Morgan; Soressi, Marie; port0228@umn.edu; Porter, Samantha T
    3D scanning is becoming an increasingly utilized tool in archaeology. In comparison with other methods of 3D registration close-range photogrammetry has the benefits of being relatively inexpensive, mobile, and extremely adaptable for use in field conditions. Here, 3D models of lithic cores from the Châtelperronian, Protoaurignacian, and Early Aurignacian levels of the site of Les Cottés (France) are presented as examples of the quality of model that can be produced using photographs taken with a simple and inexpensive photogrammetry rig.
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    Three Dimensional Models and Two Dimensional Cross Sections of Châtelperronian and Protoaurignacian Lithic Cores from the Sites of Les Cottés and Roc de Combe
    (2018-05-29) Porter, Samantha T; Roussel, Morgan; Soressi, Marie; stporter@umn.edu; Porter, Samantha T
    These data were generated as part of a study investigating the use of quantitative methods on three dimensional models of lithic artifacts. The majority of the data set is comprised of 3D scans of Châtelperronian and Protoaurignacian cores from the site of Les Cottés (France), which were generated using photogrammetry. Although cores from the site of Roc de Combe were also scanned for the associated study, we are not able to make them available here due to rights restrictions. The second part of the data set includes two dimensional representations of cross sections, which were from the 3D artifact models. These were used in two analyses, which are described in the associated publication in JCAA (see citation below).
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    Three-Dimensional Models of Experimentally-Produced Lithic Artifacts Created using Expedient and Refined Photogrammetry Protocols
    (2016-05-16) Magnani, Matthew; Douglass, Matthew; Porter, Samantha T; port0228@umn.edu; Porter, Samantha T
    The data set consists of three-dimensional (3D) models of experimentally produced lithic artifacts created using both expedient and refined photogrammetric setups and processing protocols. Source images for all models were captured using a 12.1 megapixel Canon PowerShot SX260 HS compact digital camera. In our expedient protocol, objects were placed on a wire stand. The photographer moved around the object, and captured photos using Auto mode. In our refined protocol, objects were placed on a rotating turntable under controlled lighting conditions. The camera was placed on a tripod. Shutter speed, f-stop, and ISO were set manually. This refined protocol is described in Porter, S. T., Roussel, M., & Soressi, M. (2016). A Simple Photogrammetry Rig for the Reliable Creation of 3D Artifact Models in the Field Lithic Examples from the Early Upper Paleolithic Sequence of Les Cottés (France). Advances in Archaeological Practice, 4(1), 71-86. The associated paper discusses the relative fidelity of the models produced using these different workflows. Models may also be viewed online (in browser) at: https://sketchfab.com/unlarchaeology/collections/magnani-et-al-2016.