• Applied Microscopy
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• 제46권3호
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• pp.155-159
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• 2016

This paper analyses the relationship between the distribution of a dielectric layer on the apex of a metal field electron emitter and the distribution of electron emission. Emitters were prepared by coating a tungsten emitter with a layer of epoxylite resin. A high-resolution scanning electron microscope was used to monitor the emitter profile and measure the coating thickness. Field electron microscope studies of the emission current distribution from these composite emitters (Tungsten-Clark Electromedical Instruments Epoxylite resin [Tungsten/CEI-resin emitter]) have been carried out. Two forms of image have been observed: bright single-spot images, thought to be associated with a smooth substrate and a uniform dielectric layer; and multi-spot images, though to be associated with irregularity in the substrate or the dielectric layer.

• 한국광학회지
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• 제4권1호
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• pp.9-14
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• 1993

Amplitude filter와 phase filter가 결합된 CFAP(Combined Filter of Amplitude and Phase)의 결상 특성을 조사하기 위해 Bessel beam을 도입하였다. 이 논문에서는 무수차계와 수차를 포함하는 광학계에 대한 PSF와 encircled energy(E), transmission ratio(TR), gain(G)을 Bessel beam의 node수에 따라 계산하였다. 이 결과 Bessel beam은 amplitude filter와 다른 PSF 특성을 보였으며, 또한 구면수차가 포함된 경우 compensating effect가 크게 나타났다. 특히 Bessel beam의 central spot의 size가 Airy disk 반경보다 적게 나타나므로, 고집적 반도체 소자 제작에 이용가능하리라 생각된다.

• 대한한의진단학회지
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• 제14권2호
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• pp.67-74
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• 2010

Objectives: Tongue moisture is one of major features in tongue diagnosis of Oriental Medicine. But with regard to the methods to qualify the tongue moisture level, there have been no adequate modalities to satisfy clinicians' needs. So we developed an novel device and method to quantify the tongue moisture level without contact. Methods and Materials: Ratio of saturated area to total tongue area in the image captured with a spot light at various angles was calculated. We regarded that ratio represented the moisture of tongue surface. To evaluate the performance of suggested method, we observed the correlation between conventional contact method and our method with 19 healthy subjects. Results: With comparison to conventional contact method (Schirmer test), the suggested method showed good correlation (R = 0.8602, R2 = 0.7399). Conclusion: This Method could be a convenient and robust method to evaluate tongue moisture.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.131-135
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• 2021

Numbers of studies related to optimization of design of organic light emitting diodes(OLED) through machine learning are increasing. We propose the generative method of the image to assess the performance of the device combining with machine learning technique. Principle parameter regarding dark spot growth mechanism of the OLED can be the key factor to determine the long-time performance. Captured images from actual device and randomly generated images at specific time and initial pinhole state are fed into the deep neural network system. The simulation reinforced by the machine learning technique can predict the device parameters accurately and faster. Similarly, the inverse design using multiple layer perceptron(MLP) system can infer the initial degradation factors at manufacturing with given device parameter to feedback the design of manufacturing process.

• 드라이브 ㆍ 컨트롤
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• 제17권4호
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• pp.8-14
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• 2020

Intelligent devices using ICT technology have been introduced in the field of construction machinery to improve productivity and stability. Among the intelligent devices, Machine Guidance is a device that provides real-time posture, location, and work range to drivers by installing various sensors, controllers, and satellite navigation systems on construction machines. Conversely, the efficiency of equipment that requires location information, such as machine guidance, will be greatly reduced in buildings, and tunnels in the GPS blind spots. Thus, the other high-precision positioning technologies are required in the GPS blind spot zone. In this study, we will develop a relative position measurement system that provides precise location information such as construction machinery and robots in a local area where the GPS reception is difficult. A relative position measurement system tracks a marker in the form of a sphere installed on a vehicle by using the image base tracking technology, and measures the distance and direction information to the marker to calculate a position.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.639-642
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• 2006

The intensity-hue-saturation (IHS) technique has become a standard procedure in image analysis. It enhances the colour of highly correlated data. Unfortunately, IHS technique is sensitive to the properties of the analyzed area and usually faces colour distortion problems in the fused process. This paper explores the relationship of colour between before and after the fused process and the change in colour space of images. Subsequently, the fused colours are transformed back into the 'simulative' true colours by the following steps: (1) For each pixel of fused image that match with original pixel (of the coarse spectral resolution image) is transformed back to the true colour of original pixel. (2) The value for interpolating pixels is compensated to preserve the DN ratio between the original pixel and it's vicinity. The 'compensative matrix' is constructed by the DN of fused images and simulation of scaling process. An illustrative example of a Landsat and SPOT fused image also demonstrates the simulative true colour fusion methods.

• 한국정밀공학회지
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• 제18권9호
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• pp.179-185
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• 2001

In this study, a visual sensor system for weld seam tracking the I-butt weld joints in GMA welding was constructed. The sensor system consists of a CCD camera, a diode laser with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and arc light. In order to obtain the enhanced image, quantitative relationship between laser intensity and iris number was investigated. Throughout the repeated experiments, the shutter speed was set at 1-milisecond for minimizing the effect of spatters on the image, and therefore most of the spatter trace in the image have been found to be reduced. Region of interest was defined from the entire image and gray level of searched laser line was compared to that of weld line. The differences between these gray levels lead to spot the position of weld joint using central difference method. The results showed that, as long as weld line was within $^\pm$15$^\circ$from the longitudinal straight fine, the system constructed in this study could track the weld line successful1y. Since the processing time reduced to 0.05 sec, it is expected that the developed method could be adopted to high speed welding such as laser welding.

• Journal of Mechanical Science and Technology
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• 제19권10호
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• pp.1856-1863
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• 2005

In this study, a visual sensor system for weld seam tracking the I-butt weld joints in GMA welding was constructed. The sensor system consists of a CCD camera, a diode laser with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and arc light. In order to obtain the enhanced image, quantitative relationship between laser intensity and iris opening was investigated. Throughout the repeated experiments, the shutter speed was set at 1/1000 second for minimizing the effect of spatters on the image, and therefore the image without the spatter traces could be obtained. Region of interest was defined from the entire image and gray level of the searched laser stripe was compared to that of weld line. The differences between these gray levels lead to spot the position of weld joint using central difference method. The results showed that, as long as weld line is within $\pm15^{o}$ from the longitudinal straight line, the system constructed in this study could track the weld line successfully. Since the processing time is no longer than 0.05 sec, it is expected that the developed method could be adopted to high speed welding such as laser welding.

• Journal of Information Processing Systems
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• 제18권2호
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• pp.258-267
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• 2022

Weak over-the-horizon perception and blind spot are the main problems in intelligent connected vehicles (ICVs). In this paper, a V2V image transmission-based road condition warning method is proposed to solve them. The encoded road emergency images which are collected by the ICV are transmitted to the on-board unit (OBU) through Ethernet. The OBU broadcasts the fragmented image information including location and clock of the vehicle to other OBUs. To satisfy the channel quality of the V2X communication in different times, the optimal fragment length is selected by the OBU to process the image information. Then, according to the position and clock information of the remote vehicles, OBU of the receiver selects valid messages to decode the image information which will help the receiver to extend the perceptual field. The experimental results show that our method has an average packet loss rate of 0.5%. The transmission delay is about 51.59 ms in low-speed driving scenarios, which can provide drivers with timely and reliable warnings of the road conditions.

• 한국측량학회지
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• 제23권4호
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• pp.419-426
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• 2005

최근 국토의 이용 관리측면에서 해안에 대한 관심이 증대되고 있다. 그러나 급속히 추진되어 온 다양한 연안 개발은 직간접적으로 해안선의 변화를 발생시켜 환경 문제뿐만 아니라 해안을 생활권으로 하고 있는 주민들의 생존권을 위협하는 문제를 발생시키기도 한다. CORONA 영상은 1960년대 미국에서 운행한 첩보위성영상으로, 높은 해상도의 과거 해안선 정보를 제공한다. 본 논문에서는 파노라믹 방식으로 촬영된 CORONA 위성영상에 엄밀기하보정 알고리즘을 적용하여 20m의 정확도로 1969년 동해안지역의 모자이크 영상을 제작하였다. 이를 2005년 SPOT 위성영상과 비교하여 36년 동안 발생한 해안선의 변화를 추출하였다. 추출된 해안선을 분석한 결과 일부 지역에서 상당한 크기의 해안선 침식과 퇴적이 발생한 것을 확인할 수 있었으며 고성에서 강릉까지 $0.32km^2$의 면적이 침식된 것으로 조사되었다. 조사결과는 향후 해안선 변화를 연구하는데 중요한 기초자료로 활용될 수 있을 것이다.