3D Scanning Techniques Research Articles

Applications of 3D scanning and reverse engineering techniques for quality control of quick response products

Quick error comparisons of fabricated parts and an original CAD design is often a difficult yet important issue in product quality control. In this paper we present an integrated technique of 3D scanning with reverse engineering and rapid prototyping technologies. This will be applied to the entire quality control phase of quick response products during the manufacturing process. By using 3D scanning and reverse engineering technology in conjunction with rapid prototyping technology, the geometric data of components can be easily and rapidly measured and analyzed. The detailed report can be printed out directly to fulfill the requirement of total quality control for quick response products. The proposed technique is especially suitable for fragile or soft material made products, like thin shell or rubber parts. With its accuracy and ease of operation, this integrated method is able to help manufacturers improve their global competitiveness in the 21st century.

Measurement protocol of women’s nude breasts using a 3D scanning technique

It has been difficult to obtain accurate surface data for women’s breasts, since the borderline of the breast is ambiguous at the skin surface. In this paper, we scanned 37 women’s nude breasts using 3D phase shifting moiré and explored a measurement protocol to get a reliable boundary of the breast and thereby provided new shape parameters for breasts. The folding line method was useful for finding a continuous and natural boundary for the breasts, so that the breasts base and volume could be measured more accurately. The global average radius of the curvature of the bottom breast line was suggested as a useful shape parameter for the design of a comfortable and form-fitting brassiere, especially for those who have a skewed bottom breast curve. It is also expected that data on breast volume based on natural anatomy would be a useful reference for surgical operation on the breast.

Microstructure and fracture in three dimensions

A high resolution three dimensional (3D) scanning technique called X-ray microtomography was used to measure internal crack growth in small mortar cylinders under compressive loading. Tomographic scans were made at different load increments in the same specimen. 3D image analysis was used to measure internal crack growth during each load increment. Load–deformation curves were used to measure the corresponding work of the external load on the specimen. Fracture energy was calculated using a linear elastic fracture mechanics approach using the measured surface area of the internal cracks created. The measured fracture energy was of the same magnitude that is typically measured in concrete tensile fracture. A nominally bilinear incremental fracture energy curve was measured. Separate components for crack formation energy and secondary toughening mechanisms are proposed. The secondary toughening mechanisms were found to be about three times the initial crack formation energy.

Technique to Measure 3D Work-of-Fracture of Concrete in Compression

A high-resolution 3D scanning technique called X-ray microtomography was applied to measure internal damage and crack growth in small mortar cylinders loaded in compression. Synchrotron-based microtomography allows us to resolve internal features that are only a few microns in size. Multiple tomographic scans were made of the same specimen at different levels of deformation using a custom-built loading frame. 3D image analysis was used to measure internal crack growth during each deformation increment. Measured load-deformation curves were used to calculate the nonrecoverable work of the external load on the specimen. Nonrecoverable work of load was related to measured incremental change in crack surface area to estimate work-of-fracture in three dimensions. Initial results indicate a nearly constant work-of-fracture for the early stages of crack growth. These results show that basic fracture mechanics principles may be applied to concrete in compression; however, we must think in terms of 3D multiple crack systems rather than traditional 2D single crack systems.

Comparison of 3D BOLD Functional MRI with Spiral Acquisition at 1.5 and 4.0 T

In order to investigate the merit of high field strength for BOLD-contrast-based functional magnetic resonance imaging (fMRI) studies, multishot gradient-echo fMRI experiments during motor cortex activation were performed on 1.5- and 4.0-T scanners with equivalent hardware, on the same volunteers. In these studies, artifactual vascular enhancement related to inflow effects was minimized, and large brain areas were covered by using a 3D scan technique. Temporal signal stability was optimized by using spiral readout gradients. The sensitivity for detection of activated regions was assessed by measuring the number of “activated voxels” and their averagetscore in predefined regions of interest. When comparing fMRI experiments with the same total scan time, performed on six subjects, and with acquisition parameters optimized for each field strength separately, the 4.0-T scanner proved to give superior results, with a 70% greater number of activated voxels and a 20% higher averagetscore for the activated voxels.