KEYWORDS: 3D scanning, Laser scanners, 3D image processing, Optical coherence tomography, Teeth, 3D modeling, Scanners, Clouds, Microelectromechanical systems, 3D acquisition
We report fabrication and performance of the three-dimensional intraoral scanner based on optical coherence tomography (OCT) that enables three-dimensional structure images of tooth and diagnosis of the tooth through OCT images. The OCT system was configured the swept source OCT (SS-OCT), that is based on the swept source with center wavelength of 1310 nm, the scanner was built using MEMs mirror and optical collimator. The implemented SS-OCT based on MEMs scanner show axial resolution of 10 μm, scan length of 10 mm. With OCT system, OCT 2D images of the human tooth obtained by intraoral scanner based on OCT system. 3D OCT image of the human tooth was obtained by combining the 500 2D OCT images and also included internal information and structure of the human tooth. 3D images of a human tooth obtained were sequentially stitching using the iterative closet point (ICP). By equipping the implemented SS-OCT system with MEMs probe and using ICP algorithm, the intraoral scanner based on OCT system was constructed and used to demonstrate the feasibility of intraoral scanner, that is able to acquire the structure and function images of the human tooth, for intraoral scanner 3D image in dentistry.
We describe a non-invasive and non-contact viscosity measurement system using a compact optical fiber heterodyne interferometry. The proposed system consists of a fiber based pulse laser for surface acoustic wave (SAW) excitation and a lensed fiber for probing laser. When the pulsed laser illuminates onto the oil surface, the SAW is generated by photoacoustic effect and it propagates along the surface. The interference of probing laser reflected on the sample surface has the information of the surface movement. We can calculate the propagation velocity of SAW from the detected interference signal. The propagated SAW contains the information of liquid properties (viscosity and elasticity). For the preliminary measurements, an industrial engine oil and a polydimethylsiloxane (PDMS) are used. We can measure the viscosity of them without noncontact, successfully.
We report herein the fabrication and performance response of a three-dimensional (3-D) intraoral scan probe based on optical coherence tomography (OCT) that enables 3-D structural and functional diagnoses of the human teeth. The OCT system was configured using a swept-source OCT (SS-OCT) with a center wavelength of 1310 nm. The scan probe was built using an MEMS mirror and an optical collimator. The implemented SS-OCT equipped with the MEMS-based scan probe yielded an axial resolution of 10 μm and a scan range of 8 × 8 mm2. Two-dimensional (2-D) cross-sectional images of the teeth were acquired by the scan probe based on the OCT. The 3-D volume image was acquired by combining a series of 2-D images, which includes internal and structural information of the human teeth. To utilize the OCT system as an intraoral scanner, partially overlapped 3-D volume images were sequentially acquired and stitched. The 3-D stitching was implemented based on an iterative closest point algorithm. The feasibility of the intraoral scan probe is demonstrated based on its ability to image and characterize the structure and function of the human teeth.
KEYWORDS: 3D scanning, 3D modeling, Liquid lenses, Liquids, Confocal microscopy, Clouds, Modulation, 3D image reconstruction, 3D image processing, Instrument modeling
We demonstrated a three-dimensional (3D) dental scanning apparatus based on structured illumination. A liquid lens was used for tuning focus and a piezomotor stage was used for shift of structured light. A simple algorithm, which detects intensity modulation, was used to perform optical sectioning with structured illumination. We reconstructed 3D point cloud, which represents the 3D coordinates of the digitized surface, of a dental gypsum cast by piling up sectioned images. We performed 3D registration of individual 3D point cloud, which includes alignment and merging the 3D point clouds, to exhibit a 3D model of the dental cast.
Generally, aspheric glass lenses are manufactured using a glass molding press (GMP) method and a tungsten carbide mold core. This study analyzes the thermal deformation that occurs during the GMP process, and the results were applied to compensate an aspheric glass lens. After the compensation process, the form accuracy of aspheric glass lenses improved from ∼3.7 to ∼0.35 μm. The compensated lens complied with the actual specifications.
To expand the suitable stereoscopic viewing zone on depth directional and remove the crosstalk induced by the structures of the existing slanted lenticular lens sheet, Segmented Lenticular lens having Varying Optical Power (SL-VOP) is proposed.
In this paper, the sugar content prediction determination system in optical non-contact type based on the near infrared light emitting diode (NIR-LED) lamp is proposed. As the result NIR-LED lamp reduced 86% of the energy consumption compared to the case of Halogen lamp in the same process of sugar content determination. And the result of prediction of sugar content by NIR-LED lamp is shown to as near the same level of Halogen lamp system.
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