• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.27-32
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• 2016

A new lane detection algorithm is proposed for the analysis of DNA fingerprints from a polymerase chain reaction (PCR) gel electrophoresis image. Although several research results have been previously reported, it is still challenging to extract lanes precisely from images having abrupt background brightness difference and bent lanes. We propose an edge based algorithm for calculating the average lane width and lane cycle. Our method adopts sub-pixel algorithm for extracting rising-edges and falling edges precisely and estimates the lane width and cycle by using k-means clustering algorithm. To handle the curved lanes, we partition the gel image into small portions, and track the lane centers in each partitioned image. 32 gel images including 534 lanes are used to evaluate the performance of our method. Experimental results show that our method is robust to images having background difference and bent lanes without any preprocessing.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.6-10
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• 2021

Recognition of characters printed or marked on the PCB components from images captured using cameras is an important task in PCB components inspection systems. Previous optical character recognition (OCR) of PCB components typically consists of two stages: character segmentation and classification of each segmented character. However, character segmentation often fails due to corrupted characters, low image contrast, etc. Thus, OCR without character segmentation is desirable and increasingly used via deep neural networks. Typical implementation based on deep neural nets without character segmentation includes convolutional neural network followed by recurrent neural network (RNN). However, one disadvantage of this approach is slow execution due to RNN layers. LPRNet is a segmentation-free character recognition network with excellent accuracy proved in license plate recognition. LPRNet uses a wide convolution instead of RNN, thus enabling fast inference. In this paper, LPRNet was adapted for recognizing characters printed on PCB components with fast execution and high accuracy. Initial training with synthetic images followed by fine-tuning on real text images yielded accurate recognition. This net can be further optimized on Intel CPU using OpenVINO tool kit. The optimized version of the network can be run in real-time faster than even GPU.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.68-73
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• 2022

In this study, we produced the surface defect detection model to automatically detect defect bone plates using a deep learning algorithm. Bone plates with a width and a length of 50 mm are most used for fracture treatment. Normal bone plates and defective bone plates were printed on the 3d printer. Normal bone plates and defective bone plates were photographed with 1,080 pixels using the webcam. The total quantity of collected images was 500. 300 images were used to learn the defect detection model. 200 images were used to test the defect detection model. The mAP(Mean Average Precision) method was used to evaluate the performance of the surface defect detection model. As the result of confirming the performance of the surface defect detection model, the detection accuracy was 96.3 %.

• 핵의학기술
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• 제20권2호
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• pp.49-53
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• 2016

최근 Cadmium-zinc-telluride (CZT) 반도체를 이용한 심장전용 감마카메라가 심장 핵의학 검사에 사용되고 있다. 본 연구는 기존 NaI(Tl) 신틸레이터를 사용한 감마카메라와 성능을 비교해 보고자 한다. CZT반도체를 사용한 심장전용 감마카메라(DSPECT, Spectrum-dynamic)와 범용 신틸레이터 SPECT 감마카메라(Infinia, GE)를 사용하여 연구를 진행했다. 방사성 동위원소는 $^{99m}TcO^{-4}$를 사용하고, 일반 임상 심장핵의학 검사에 사용된 조건을 실험 조건으로 설정 했다. NEMA 2001, 3 line phantom을 사용하여 반치폭(full width at half maximum, FWHM)을 측정하여 공간분해능(Spatial resolution)을 비교했다. 심장 팬텀을 사용하여 대조도대잡음비(Contrast to noise, CNR)를 비교하여 영상을 평가했다. 그리고 팬텀의 시간 당 MBq당 계수를 측정하여 민감도도 평가했다. NaI (Tl) 신틸레이터를 사용한 범용SPECT 감마카메라와 CZT 반도체를 사용한 심장 전용 감마카메라의 영상평가에서 감도는 $52.83counts{\cdot}sec^{-1}{\cdot}MBq^{-1}$과 $195.83counts{\cdot}sec^{-1}{\cdot}MBq^{-1}$로 나왔고, 공간분해능은 16.90 mm과 9.47 mm로 나왔다. 그리고 대조도대 잡음비는 3.6 과 4.2 로 나왔다. 기존 카메라를 이용한 심장 핵의학 영상과 비교하여 CZT를 사용한 심장 전용 감마카메라는 감도 및 공간분해능, 대조도대잡음비가 기존 감마카메라와 비교하여 월등하여 임상에서 환자의 피폭선량 저감과 검사 시간 단축, 높은 분해능의 영상으로 환자 만족도에 큰 영향을 줄 것으로 사료 된다.

• Imaging Science in Dentistry
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• 제47권4호
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• pp.233-239
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• 2017

Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor(CMOS) intraoral sensor. Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis. Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and inter-observer agreement was achieved. Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.881-884
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• 2004

The robust and large-area applicable metal shadow masks with a high aspect ratio more than 20 are fabricated by a combination of micro-electro-discharge machining (${\mu}$-EDM) and electro chemical etching (ECE). After defining S/D contacts using a 100 ${\mu}m$ thick stainless steel shadow mask, the top-contact pentacene TFTs with channel length of 5 ${\mu}m$ showed routinely the results of mobility of 0.498 ${\pm}$ 0.05 $cm^2$/Vsec, current on/off ratio of 1.6 ${times}$ $10^5$, and threshold voltage of 0 V. The straightly defined atomic force microscopy (AFM) images of channel area demonstrated that shadow effects caused by the S/D electrode deposition were negligible. The fabricated pentacene TFTs have an average channel length of 5 ${\pm}$ 0.25 ${\mu}m$.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.44-49
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• 2022

The number of single-person households is increasing worldwide, and among them, the proportion of elderly single-person households is increasing. In the case of elderly single-person households, a significant portion of their leisure time is devoted to watching TV. However, if they fall asleep while watching TV without turning it off, it may be difficult to sleep well due to lights and sounds of TV, which can cause health problems such as depression and reduced immunity. Therefore, in this paper, we propose a system that automatically turns off the TV when a person watching TV falls asleep. Images are collected using the camera installed in front of the TV. Since the posture of a person watching TV varies from a sitting posture to a lying posture, the system is designed to determine whether or not to fall asleep regardless of the posture. In addition, since it becomes difficult to judge eye movements as a person moves away from the TV, a method for extending the judgmentable distance is proposed. The system model was implemented and tested using a Raspberry Pi, a monitor, an infrared sensor, and a camera. Eye movements were judged regardless of sitting or lying position, and the distance between a user and a TV was extended by about 200 cm.

• Applied Science and Convergence Technology
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• 제25권5호
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• pp.85-87
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• 2016

Coincidence Doppler broadening and positron lifetime methods in positron annihilation spectroscopy has been used to analyze defect structures in metal, semiconductor and polycrystal, respectively. The S parameter and the lifetime (${\tau}$) value show that the defects were strongly related with vacancies. A positive relationship existed between the scanning electron microscope (SEM) images and the positron annihilation spectroscopy (PAS). According to the SEM images and PAS results, measurements of the defects with PAS indicate that it was more affected by the defect than the purity.

• Journal of Information Display
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• 제2권3호
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• pp.66-71
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• 2001

MCFEDs (MOSFET-Contoolled Field Emission Displays) were fabricated to evaluate the validity of MCFEA for display application. The electrical properties of FEAs (Field Emitter Arrays), HVMOSFETs (High-Voltage MOSFETs), and MCFEAs (MOSFET-Controlled Field Emitter Arrays) were measured. The extraction gate voltage of the FEAs to obtain the anode current of 10 nA/tip was around 71 V. The breakdown voltages of the HVMOSFETs were above 81 V for all the samples. The I-V characteristics of the MCFEAs showed that the emission currents of the FEAs were well controlled depending on the control gate voltages of the HVMOSFETs. To avoid the harmful effects during the packaging process, the performance of the MCFEDs was evaluated in a high vacuum chamber. The emission images of the MCFEDs were controlled through very-through operation. From the comparison with a conventional FED, it was proven that the poor uniformity of FED could be improved through the integration with HVMOSFET.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.109.1-109.1
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• 2015

Understanding the reaction mechanisms and structures underlying the adsorption of biomolecules on semiconductors is important for functionalizing semiconductor surfaces for various bioapplications. Herein, we describe the characteristic behavior of a primary nucleobase adsorbed on the semiconductor Ge(100). The adsorption configuration of guanine, a primary nucleobase found in DNA and RNA, on the semiconductor Ge(100) at an atomic level was investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. When adsorbed on Ge(100) at room temperature, guanine appears dark in STM images, indicating that the adsorption of guanine on Ge(100) occurs through N-H dissociation. In addition, DFT calculations revealed that "N(1)-H dissociation through an O dative bonded structure" is the most favorable adsorption configuration of all the possible ones. We anticipate that the characterization of guanine adsorbed on Ge(100) will contribute to the development of semiconductor-based biodevices.