• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.633-644
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• 2020

Rice paper is an element of Vietnamese cuisine that can be used to wrap vegetables and meat. Rice and starch are the main ingredients of rice paper and their mixing ratio is important for quality control. In a commercial factory, assessment of food safety and quantitative supply is a challenging issue. A rapid and non-destructive monitoring system is therefore necessary in commercial production systems to ensure the food safety of rice and starch flour for the rice paper wrap. In this study, fluorescence hyperspectral imaging technology was applied to classify grain flours. Using the 3D hyper cube of fluorescence hyperspectral imaging (fHSI, 420 - 730 nm), spectral and spatial data and chemometric methods were applied to detect and classify flours. Eight flours (rice: 4, starch: 4) were prepared and hyperspectral images were acquired in a 5 (L) × 5 (W) × 1.5 (H) cm container. Linear discriminant analysis (LDA), partial least square discriminant analysis (PLSDA), support vector machine (SVM), classification and regression tree (CART), and random forest (RF) with a few preprocessing methods (multivariate scatter correction [MSC], 1^st and 2^nd derivative and moving average) were applied to classify grain flours and the accuracy was compared using a confusion matrix (accuracy and kappa coefficient). LDA with moving average showed the highest accuracy at A = 0.9362 (K = 0.9270). 1D convolutional neural network (CNN) demonstrated a classification result of A = 0.94 and showed improved classification results between mimyeon flour (MF)1 and MF2 of 0.72 and 0.87, respectively. In this study, the potential of non-destructive detection and classification of grain flours using fHSI technology and machine learning methods was demonstrated.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.205-205
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• 2004

• Geophysics and Geophysical Exploration
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• v.4 no.4
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• pp.101-109
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• 2001

In order to develop a spatial information system that can efficiently manage various subsurface data and produce information in a proper form for a user, we established a database of the well cores and built 3-D shapes that visualize the subsurface objects such as wells, ore bodies, tunnels, and mine cavities. We also made analysis tools available for three-dimensional ore bodies constructed here, such as vertical cross-section generator and mass computing tool. This system was developed by coding Avenue, a scripting language incorporated in ArcView, which is a commercial GIS software. Using the system, it is expected that users can make fast and accurate analysis and interpretation through real-time queries and by contemplating various objects in 3-D perspective.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.220-220
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• 2013

Surface-normal transmission electro-absorption modulator (EAM) are attractive for high-definition (HD) three-dimensional (3D) imaging application due to its features such as small system volume and simple epitaxial structure [1,2]. However, EAM in order to be used for HD 3D imaging system requires uniform modulation performance over large area. To achieve highly uniform modulation performance of EAM at the operating wavelength of 850 nm, it is extremely important to remove the GaAs substrate over large area since GaAs material has high absorption coefficient below 870 nm which corresponds to band-edge energy of GaAs (1.424 eV). In this study, we propose and experimentally demonstrate a transmission EAM in which highly selective backside etching methods which include lapping, dry etching and wet etching is carried out to remove the GaAs substrate for achieving highly uniform modulation performance. First, lapping process on GaAs substrate was carried out for different lapping speeds (5 rpm, 7 rpm, 10 rpm) and the thickness was measured over different areas of surface. For a lapping speed of 5 rpm, a highly uniform surface over a large area ($2{\times}1\;mm^2$) was obtained. Second, optimization of inductive coupled plasma-reactive ion etching (ICP-RIE) was carried out to achieve anisotropy and high etch rate. The dry etching carried out using a gas mixture of SiCl4 and Ar, each having a flow rate of 10 sccm and 40 sccm, respectively with an RF power of 50 W, ICP power of 400 W and chamber pressure of 2 mTorr was the optimum etching condition. Last, the rest of GaAs substrate was successfully removed by highly selective backside wet etching with pH adjusted solution of citric acid and hydrogen peroxide. Citric acid/hydrogen peroxide etching solution having a volume ratio of 5:1 was the best etching condition which provides not only high selectivity of 235:1 between GaAs and AlAs but also good etching profile [3]. The fabricated transmission EAM array have an amplitude modulation of more than 50% at the bias voltage of -9 V and maintains high uniformity of >90% over large area ($2{\times}1\;mm^2$). These results show that the fabricated transmission EAM with substrate removed is an excellent candidate to be used as an optical shutter for HD 3D imaging application.

• Journal of the Korea Computer Industry Society
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• v.9 no.3
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• pp.105-114
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• 2008

We present an eye tracking system using a low cost 3D CMOS imager for 3D displays that ensures a correct auto stereoscopic view of position- dependent stereoscopic 3D images. The tracker is capable of segmenting the foreground objects (viewer) from background objects using their relative distance from the camera. The tracker is a novel 3D CMOS Image Sensor based on Time of Flight (TOF) principle using innovating photon gating techniques. The basic feature incorporates real time depth imaging by capturing the shape of a light-pulse front as it is reflected from a three dimensional object. The basic architecture and main building blocks of a real time depth CMOS pixel are described. For this application, we use a stereoscopic type of display using parallax barrier elements that is described as well.

• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.33-41
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• 2015

This study attempts to examine the clinical usefulness of High b-value DWI (diffusion weighted imaging) for brain tumors with an edema. Subjects were seven patients selected from 65 patients who received an MRI scan for suspected encephalopathy and confirmed diagnosis at our hospital from February to July 2015 (male: 7, average age : 66 years old). As test equipment, 3.0T MR System (ACHIEVA Release, Philips, Best, The Netherlands) and 8Channel SENSE Head Coill were used. DWI checks on the use of the variable TR 5460ms, TE 132ms, Slice Thickness 4mm, gap 1mm, Slice number 29 is, 3D T1WI is TR 8.4ms, TE 3.9ms, matrix size $240{\times}240$, Slice can set 180 piecesIt was. b value of 0, 1,000, 2,000 s/mm2 with DWI acquisition and 3D T1WI enhancement five minutes after the Slice Thickness 3mm, gap 0mm to reconstruct the upper face axis (MPR TRA CE) was. As for the experiment, in b-value 1,000 and 2,000 images, SNR and the lesion at the lesion site and CNR in the normal site opposite to the lesion are measured. WW(window width) and WL(window level) are made equal in MRICro software, and the volume of the lesion is measured from each of b-value and MPR TRA CE image. Using SPSS ver. 1.8.0.0 Mann Whitney-test was analyzed for SNR and CNR, while Kruskal-Wallis test was analyzed for volume.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.272-288
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• 2014

This paper presents a two-step, semi-automated method for reconstructing a three-dimensional (3D) shape of the prostate from a 3D transrectal ultrasound (TRUS) image. While the method has been developed for prostate ultrasound imaging, it can potentially be applicable to any other organ of the body and other imaging modalities. The proposed method takes as input a 3D TRUS image and generates a watertight 3D surface model of the prostate. In the first step, the system lets the user visualize and navigate through the input volumetric image by displaying cross sectional views oriented in arbitrary directions. The user then draws partial/full contours on selected cross sectional views. In the second step, the method automatically generates a watertight 3D surface of the prostate by fitting a deformable spherical template to the set of user-specified contours. Since the method allows the user to select the best cross-sectional directions and draw only clearly recognizable partial or full contours, the user can avoid time-consuming and inaccurate guesswork on where prostate contours are located. By avoiding the usage of noisy, incomprehensible portions of the TRUS image, the proposed method yields more accurate prostate shapes than conventional methods that demand complete cross-sectional contours selected manually, or automatically using an image processing tool. Our experiments confirmed that a 3D watertight surface of the prostate can be generated within five minutes even from a volumetric image with a high level of speckles and shadow noises.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.1
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• pp.24-30
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• 2011

We have developed a hand-held probe for an ophthalmic OCT system. The hand-held probe for imaging was designed to be compact and portable. The cornea and retinal images were acquired by replacing the objective lens at the front of the probe. To verify the performance of the hand-held OCT probe, we acquired two dimensional OCT image of the rat eye in vivo and reconstructed three dimensional rat eye rendering images. In vivo 3D OCT images were showed distinct structural information in the posterior and anterior chamber with minimal motion artifacts. Thereby, OCT imaging speed is suitable for an dynamic in vivo experiment.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.55-68
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• 2014

Some infrastructure these days is usually constructed under the ground for it to not interfere the foot-traffic of pedestrians, and thus, it is difficult to visually confirm the accurate location of the site where the establishments must be buried. These technical difficulties increase the magnitude of the problems that could arise from over-reliance on the experience of the worker or a mere blueprint. Such problems include exposure to flood and collapse. This paper proposes a constructor-oriented visualization system via mobile gadgets in general construction sites with occluded structures. This proposal is consisted with three stages. First, "Stage of detecting manhole and extracting features" detects and extracts the basis point of occluded structures which is unoccluded manhole. Next, "Stage of tracking features" tracks down the extracted features in the previous stage. Lastly, "Stage of visualizing occluded constructions" analyzes and synthesizes the GPS data and 3D objects obtained from mobile gadgets in the previous stages. This proposal implemented ideal method through parallel analysis of manhole detection, feature extraction, and tracking techniques in indoor environment, and confirmed the possibility through occluded water-pipe augmentation in real environment. Also, it offers a practical constructor-oriented environment derived from the augmented 3D results of occluded water-pipings.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.303-310
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• 2015

An image-space telecentric lens for an intra-oral 3D scanner was designed and fabricated for dental application. Since a telecentric function can provide the same results regardless of image plane position, it helps to realize a more accurate image for an intra-oral scanner. The performance of the designed lens meets the required properties for HD resolution. In particular, lateral color is corrected within 1 pixel. This system achieves depth of focus of more than 3 mm. For user convenience, the developed system consists of a prism part and an imaging part. Both parts are optimized to reduce the front size and weight of the system. In order to make the parallax sights, parallax angle was determined to be 8 degrees between two optical systems.