• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1255-1258
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• 2008

Roll to roll (R2R) system, known as 'web processing', is the process of producing these electronic devices on a roll of flexible plastic. With the need of improved performance and productivity in R2R industry, effective control and on-line supervision for web quality is essential. In this report, we present a system for on-line measurement of wrinkles, one of defects incurring due to compressive stresses developed in the web. This system is able to capture an image generated when a well defined line shape laser beam passes through a transparent web. The system calculates 3D shape information, including the height of the wrinkle on the web, and displays the images for the shape information of the web in real time. By using area scan camera and machine vision laser, this system takes more advantages of setting up as a simple and low cost system compared to the line scan camera systems that widely used in web manufacturing. Specific calibration method and analysis on the achievable accuracy will be discussed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.1-6
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• 2023

In the realm of dental prosthesis fabrication, obtaining accurate impressions has historically been a challenging and inefficient process, often hindered by hygiene concerns and patient discomfort. Addressing these limitations, Company D recently introduced a cutting-edge solution by harnessing the potential of intraoral scan images to create 3D dental models. However, the complexity of these scan images, encompassing not only teeth and gums but also the palate, tongue, and other structures, posed a new set of challenges. In response, we propose a sophisticated real-time image segmentation algorithm that selectively extracts pertinent data, specifically focusing on teeth and gums, from oral scan images obtained through Company D's oral scanner for 3D model generation. A key challenge we tackled was the detection of the intricate molar regions, common in dental imaging, which we effectively addressed through intelligent data augmentation for enhanced training. By placing significant emphasis on both accuracy and speed, critical factors for real-time intraoral scanning, our proposed algorithm demonstrated exceptional performance, boasting an impressive accuracy rate of 0.91 and an unrivaled FPS of 92.4. Compared to existing algorithms, our solution exhibited superior outcomes when integrated into Company D's oral scanner. This algorithm is scheduled for deployment and commercialization within Company D's intraoral scanner.

• Progress in Medical Physics
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• v.7 no.2
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• pp.67-77
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• 1996

Purpose: To get a 3-D coordinates of intracranial target position was investicated in axial, sagittal and coronal magnetic resonance imaging with a preliminary experimented target localizer. Material and methods : In preliminal experiments, the localizer is made of engineering plastic to avoid the distrubance of magnetic field during the MR image scan. The MR localizer displayed the 9 points in three different axial tomogram. The bright signal of localizer was obtjained from 0.1～0.3％ of paramagnetic gadolinium/DTPA solution in T1WI or T2WI. In this study, the 3-D position of virtual targets were examined from three different axial MR images and the streotactic position was compared to that of BRW stereotactic system in CT scan with same targets. Results: This study provided the actual target position could be obtained from single scan with MRI localizer which has inverse N-typed 9 bars. This experiment was accomplished with shimming test for detection of image distortion in MR image. However we have not found the image distortion in axial scan. The maximum error of target positions showed 1.0 mm in axial, 1.3 mm for sagittal and 1.7 mm for coronal image, respectivelly. The target localization in MR localizer was investicated with spherical virtual target in skull cadaver. Furthermore, the target position was confirmed with CRW stereotactic system showed a 1.3 mm in discrepancy. Summary : The intracranial target position was determined within 1.7 mm of discrepancy with designed MR localizer. We found the target position from axial image has more small discrepancy than that of sagittal and coronal image.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.2
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• pp.158-168
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• 2015

This article describes how to use digital system in a fully edentulous case that diagnosis to definitive prosthesis fabrication. While proceeding oral scan and CBCT taking, digital markers were attached on maxillary palate and lower existing denture. Using CBCT image and oral scan image, the bone contour and anatomical structures were analyzed and flapless surgical guide, customized abutment and prosthesis were made. After the osseointegration, the definitive prosthesis was fabricated using the oral scan image with scan body. It provides clinicians with a fast workflow and improves clinical efficiency.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.81-88
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• 2007

The geometry of satellite image captured by linear CCD sensor is different from that of frame camera image. The fact that the exterior orientation parameters for satellite image with linear CCD sensor varies from scan line by scan line, causes the difference of image geometry between frame and linear CCD sensor. Therefore, we need the epipolar geometry for linear CCD image which differs from that of frame camera image. In this paper, we proposed a method of resampling linear CCD satellite image in epipolar geometry under the assumption that image is not formed in perspective projection but in parallel projection, and the sensor model is a 2D affine sensor model based on parallel projection. For the experiment, IKONOS stereo images, which are high resolution linear CCD images, were used and tested. As results, the spatial accuracy of 2D affine sensor model is investigated and the accuracy of epipolar resampled image with RFM was presented.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.9
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• pp.991-999
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• 2013

Lower limbs deformity is a congenital disease and can also be occurred by an acquired factor. This paper suggests a new technique for surgical planning of Corrective Osteotomy for Lower Limbs (COLL) using 2D-3D medical image registration. Converting to a 3D modeling data of lower limb based on CT (computed tomography) scan, and divide it into femur, tibia and fibula; which composing the lower limb. By rearranging the model based on the biplane 2D images of X-ray data, a 3D upright bone structure was acquired. There are two ways to array the 3D data on the 2D image: Intensity-based registration and feature-based registration. Even though registering Intensity-based method takes more time, this method will provide more precise results, and will improve the accuracy of surgical planning.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.896-897
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• 2015

본 연구는 3D 이미지 스캔 데이터 기반으로, SWEEPING 형상을 효과적으로 역설계하는 기술에 관한 것이다. 사용자가 미리 정의한 형상 단면 모델 데이터베이스를 이용해, 3차원 SWEEPING 형상을 자동으로 역설계하는 알고리즘을 제안한다. 이를 위해, 3D 이미지 스캔 데이터인 포인트 클라우드에서 자동으로 추출한 단면 포인트들을 처리해, 파라메터 정보를 추출하고, 미리 정의된 형상 단면들과 상호간 유사도를 비교한 후, 가장 유사한 형상 단면을 획득한다. 이러한 기술은 SWEEPING 형상 모델의 역설계 과정을 자동화하는 데 도움을 줄 것이다.

• Investigative Magnetic Resonance Imaging
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• v.14 no.1
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• pp.56-63
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• 2010

Purpose : DIR image is relatively free from susceptibility artifacts therefore, DIR image can make it possible to reliably measure cortical thickness/volume. One drawback of the DIR acquisition is the long scan time to acquire the fully sampled 3D data set. To solve this problem, we applied a parallel imaging method (GRAPPA) and verify the reliability of using the volumetric study. Materials and methods : Six healthy volunteers (3 males and 3 females; age $25.33{\pm}2.25$ years) underwent MRI using the 3D DIR sequence at a 3.0T Siemens Tim Trio MRI scanner. GRAPPA simulation was performed from the fully sampled data set for reduction factor 2. Data reconstruction was performed using MATLAB R2009b. Freesurfer v.4.3.0 was used to evaluate the cortical thickness of the entire brain, and to extract white matter information from the DIR image, Analyze 9.0 was used. The global cortical thickness estimated from the reconstructed image was compared with reference image by using a T-test in SPSS. Results : Although reduced SNR and blurring are observed from the reconstructed image, in terms of segmentation the effect was not so significant. The volumetric result was validated that there were no significant differences in many cortical regions. Conclusion : This study was performed with DIR image for a volumetric MRI study. To solve the long scan time of 3D DIR imaging, we applied GRAPPA algorithm. According to the results, fast imaging can be done with reduction factor 2 with little loss of image quality at 3.0T.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1225-1233
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• 2008

In this paper, the 2D/3D converting algorithm is proposed. The single frame of 2D image is used fur the real-time processing of the proposed algorithm. The proposed algorithm creates a 3D image with the depth map by using the vertical position information of a object in a single frame. In order to real-time processing and improve the hardware complexity, it performs the generation of a depth map using the image sampling, the object segmentation with the luminance standardization and the boundary scan. It might be suitable to a still image and a moving image, and it can provide a good 3D effect on a image such as a long distance image, a landscape, or a panorama photo because it uses a vertical position information. The proposed algorithm can adapt a 3D effect to a image without the restrictions of the direction, velocity or scene change of an object. It has been evaluated with the visual test and the comparing to the MTD(Modified Time Difference) method using the APD(Absolute Parallax Difference).

• Journal of Biomedical Engineering Research
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• v.39 no.3
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• pp.116-123
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• 2018

This study is a model experimental study using a phantom to propose an optimized brain CT scan protocol that can reduce the radiation dose of a patient and remain quality of image. We investigate the CT scan parameters of brain CT in clinical medical institutions and to measure the important parameters that determine the quality of CT images. We used 52 multislice spiral CT (SOMATOM Definition AS+, Siemens Healthcare, Germany). The scan parameters were tube voltage (kVp), tube current (mAs), scan time, slice thickness, pitch, and scan field of view (SFOV) directly related to the patient's exposure dose. The CT dose indicators were CTDIvol and DLP. The CT images were obtained while increasing the imaging conditions constantly from the phantom limit value (Q1) to the maximum value (Q4) for AAPM CT performance evaluation. And statistics analyzed with Pearson's correlation coefficients. The result of tube voltage that the increase in tube voltage proportionally increases the variation range of the CT number. And similar results were obtained in the qualitative evaluation of the CT image compared to the tube voltage of 120 kVp, which was applied clinically at 100 kVp. Also, the scan conditions were appropriate in the tube current range of 250 mAs to 350 mAs when the tube voltage was 100 kVp. Therefore, by applying the proposed brain CT scanning parameters can be reduced the radiation dose of the patient while maintaining quality of image.