3D Scanning Analysis Research Articles

Durability of Japanese-earth cob walls subjected to accelerated rain simulation

Earthen materials are increasingly being recognized in architecture for their low embodied energy, recyclability, and hygrothermal properties. However, the common use of manufactured stabilizers, while enhancing weathering resistance, compromises these merits. Japan, known for its typhoons, has used unstabilized earth in construction for centuries, suggesting the viability of this construction material. While architecture around the world attests to its resilience, in-depth research into unstabilized earthen material is limited. This study examines unstabilized earth durability through 90-min accelerated rain simulation tests, totaling over 6500 mm of “rain” exposure on each of twelve test surfaces (eight representing rural Japanese cob-ball construction and four, monolithic cob walls). Surface changes were monitored by 3D scans performed at seven intervals. The test walls were built using two common materials in Japanese earthen wall craft, sourced from the areas of Kashiba and Fukakusa. It was clear from 3D-scan analysis that the base-layer material, Kashiba, is remarkably resistant to weathering. The four monolithic Kashiba test surfaces, constructed on four different foundation types, respectively eroded just 1 mm, 2.6 mm, 3.8 mm, and 3.9 mm. These results corroborate traditional building practices. Thus, our study also underscores the value of incorporating knowledge from vernacular earthen architecture professionals in expediting academic research. Additionally, our results suggest the potential of hose-showerhead tool use for research, and for on-site testing of earthen material erosion levels for material adequacy.

Assessment of the chipping process of beech (Fagus sylvatica L.) wood: knives wear, chemical and microscopic analysis of wood

ABSTRACT The objective of this work was to investigate the rate of knife wear during the beech wood chipping process and to evaluate the changes in the chemical and microscopic structure of wood. A knife coated with AlCrN was selected for the study. This coating creates an abrasion resistant layer on the knife and has a higher resistance to abrasive wear and, therefore, a longer life. After chipping, the degree of knife wear was assessed using a gravimetric method and 3D scanning analysis. Microstructural and surface characterisation revealed that cracking and abrasive wear were the main causes of tool blunting. The maximum removal of material on the cutting edge was 240 µm, the average weight loss of 0.58 g. In relation to wear, wood fragments remained on the cutting knife. Infrared spectroscopy of wood fragments showed changes in the chemical composition due to the high temperatures in the blade of the knife, and elemental analysis, the higher content of Al, Cr, and N elements in the wood fragments, probably due to the presence of particles from the coating of the knives. Microscopic analysis of the chips revealed the presence of metal particles from the knives on the structural wood elements.

Clinical classification of scoliosis patients using machine learning and markerless 3D surface trunk data.

Markerless 3D surface topography for scoliosis diagnosis and brace treatment can avoid repeated radiation known from standard X-ray analysis and possible side effects. Combined with the method of torso asymmetry analysis, curve severity and progression can be evaluated with high reliability. In the current study, a machine learning approach was utilised to classify scoliosis patients based on their trunk surface asymmetry pattern. Frontal X-ray and 3D scanning analysis with a clinical classification based on Cobb angle and spinal curve pattern were performed with 50 patients. Similar as in a previous study, each patient's trunk 3D reconstruction was used for an elastic registration of a reference surface mesh with fixed number of vertices. Subsequently, an asymmetry distance map between original and reflected torso was calculated. A fully connected neural network was then utilised to classify patients regarding their Cobb angle (mild, moderate, severe) and an Augmented Lehnert-Schroth (ALS) classification based on their full torso asymmetry distance map. The results reveal a classification success rate of 90% (SE: 80%, SP: 100%) regarding the curve severity (mild vs moderate-severe) and 50-72% regarding the ALS group. Identifying patient curve severity and treatment group was reasonably possible allowing for a decision support during diagnosis and treatment planning. Graphical abstract.

Innovative decision support for scoliosis brace therapy based on statistical modelling of markerless 3D trunk surface data

Recently markerless 3D scanning methods receive an increased interest for therapy planning and brace treatment of patients with scoliosis. This avoids repeated radiation known from standard X-Ray analysis. Several authors introduced the method of asymmetry distance maps in order to classify curve severity and progression. The current work extends this approach by statistical mean shape 3D models of the human trunk in order to classify patients. 50 patients were included in this study performing frontal X-ray and 3D scanning analysis. All patients were classified by a clinician according to their Cobb angle and spinal curve pattern (Augmented-Lehnert-Schroth ALS). 3D reconstructions of each patient trunk were processed in a way to elastically register a reference surface mesh with fixed number of data points. Mean 3D shape models were generated for each curve pattern. An asymmetry distance map was then calculated for each patient and mean shape model. Single patient 3D reconstructions were classified according to severity and ALS treatment group. Optimal sensitivity and specificity was 97%/39% thoracic and 87%/42% lumbar respectively for detecting mild and moderate-severe patients. Identifying a treatment group was possible for three combined groups allowing to support decisions during diagnosis and therapy planning.

Idiopathic scoliosis and breast asymmetry

The aim of this study is to describe the semiology for the assessment of breast asymmetry in the presence of scoliosis. Twenty-four women with right idiopathic scoliosis treated with bracing alone (23 out of 24) or with bracing and spine surgery (1 out of 24) were evaluated by physical and morphological examinations and three-dimensional (3D) surface scan. Physical examination revealed a smaller right breast in 20 women. A left costal protrusion was observed in 18 patients. Anthropomorphic analysis revealed that the right breast was higher in 19 cases, and smaller in 18 cases. The calculations from 3D scan showed the right breast to be smaller in 19 women. A strong correlation is found between clinical parameters, anthropomorphic measurements and 3D scan analysis, suggesting that a meticulous clinical examination is sufficient to evaluate breast asymmetry in patients with idiopathic scoliosis. A patient who is properly diagnosed and informed of her skeletal deformity and breast asymmetry is more likely to have realistic expectations from breast surgery.