• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.9 no.2
• /
• pp.212-216
• /
• 1999

SiC(3C) photodiodes (PDs) were fabricated on p-type Si(111) substrates using chemical vapor deposition (CVD) technique by pyrolyzing tetramethylsilane (TMS) with $H_{2}$ carrier gas. Electrical properties of SiC(3C) were investigated by Hall measurement and current-voltage (I-V) characteristics. SiC(3C) layers exhibited n-type conductivity. Ohmic contact was formed by thermal evaporation Al metal through a shadow-mask. The optical gain $(G_{op})$ of the SiC(3C)/Si PD was measured as a function of the incident wavelength. For the analysis of the photovoltaic detection of the Sic(3C) n/p PD, the spectral response (SR) has calculated by using the electrical parameters of the SiC(3C) layer and the geometric structure of the PD. The peak response calculated for properly chosen parameters was about 0.75 near 550 nm. We expect a good photoresponse in the SiC(3C) heterostructure for the wavelength range of 400~600 nm. The SiC(3C) photodiode can detect blue and near ultraviolet (UV) radiation.

• Journal of IKEEE
• /
• v.19 no.1
• /
• pp.10-17
• /
• 2015

In this Paper, an efficient method of FPGA based design and implementation of Sobel Edge detector block using 3-Line buffers is presented. The FPGA provides the proper and sufficient hardware for image processing algorithms with flexibility to support Sobel edge detection algorithm. A pipe-lined method is used to implement the edge detector. The proposed Sobel edge detection operator is an model using of Finite State Machine(FSM) which executes a matrix mask operation to determine the level of edge intensity through different of pixels on an image. This approach is useful to improve the system performance by taking advantage of efficient look up tables, flip-flop resources on target device. The proposed Sobel detector using 3-line buffers is synthesized with Xilinx ISE 14.2 and implemented on Virtex II xc2vp-30-7-FF896 FPGA device. Using matlab, we show better PSNR performance of proposed design in terms of 3-Line buffers utilization.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.9
• /
• pp.2043-2052
• /
• 1997

The object-oriented coding technique which is one of the coding methods in very low bit rate environment is suitable for videophone image sequence. The selection of source model affect image analysis. In this paper, an image analysis method for the object-oriented coding is presented. The process is composed of changed region detection andmotion estimateion. First, we use the standard deviation of frame difference as thrreshold to extract themoving area. If thesum of gray values in mask is greater than the threshold, the center pixel of the mask is regarded as moving region. After moving is detected in changed region by edge operator, observation point is determined from moving region. The motion is estimated by 6-parameter mapping method with determined observation point. The experimantal resutls show that the proposed method can significantly improve the image quality.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.1
• /
• pp.100-107
• /
• 2012

Recently the need for advanced security technologies are increasing as the occurrence of intelligent crime is growing fastly. Previous methods for face disguise detection are required for the improvement of accuracy in order to be put to practical use. In this paper, we propose a new disguise detection method using the template matching and Adaboost algorithm. The proposed system detects eyes based on multi-scale Gabor feature vector in the first stage, and uses template matching technique in oreder to increase the detection accuracy in the second stage. The template matching plays a role in determining whether or not the person of the captured image has sunglasses on. Adaboost algorithm is used to determine whether or not the person of the captured image wears a mask. Experimental results indicate that the proposed method is superior to the previous methods in the detection accuracy of disguise faces.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.2
• /
• pp.32.3-32.3
• /
• 2016

Available VLBI sources at high frequencies (e.g. >22GHz) are very limited - mainly due to atmospheric fluctuations that degrade coherence time and a power-law energy distribution of particles in case of AGNs. However, simultaneous multi-frequency VLBI receiving system of the Korean VLBI Network (KVN) and its powerful VLBI phase calibration technique offer benefits in finding more weak sources at millimeter wavelengths. Based on this aspect, multi-frequency AGN survey with the KVN (MASK) project, which aims to densify an existing a VLBI catalog of extragalactic radio sources at 22/43/86/129GHz is proposed as a KVN legacy program. We selected 1220 sources of AGNs that include known VLBI sources and new fringe-detected sources using the KVN at K-band (22GHz). Among them, 138 sources were observed as pilot experiments at 22/43/86/129GHz simultaneously and excellent VLBI detection results are achieved. Therefore, we expect that MASK will open a new era in VLBI science at millimeter wavelengths by providing unprecedented number of available sources in the Universe.

• Journal of Korea Multimedia Society
• /
• v.12 no.8
• /
• pp.1073-1081
• /
• 2009

In this paper, we proposed new method to enhance choroidal vessels by suppressing retina vessels brightness. It is well-known that CNV(choroidal neovascularization) is related with sight loss. The main feature of CNV is the occurrence of new vessels in choroid. Unfortunately, because retina vessels brightness is stronger than choroidal vessels brightness in ICGA(indocynanine green angiography) image, so that the choroidal vessels were hardly recognized. Therefore, for correct diagnosis, the choroidal vessels must be enhanced in ICGA image. The proposed enhancement method consists of 3 strategies. First, the retina vessels were detected by multi scale enhancement technique, hysteresis thresholding, KNN(Kth-nearest neighbor) classification method. And then, a retina vessel mask was generated from detection result. Next, the brightness of retina vessels was suppressed by the proposed conditional region erosion method and mask region until the mask region was vanished. Finally, the brightness of choroidal vessel was enhanced on processed image. Through an experiment, we had confirmed that the proposed method was robust and efficient.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.906-911
• /
• 2004

In this paper, we used only PR as etching mask, while it used usually Cr/AU as etching mask, and in order to fabricate a photosensor has the increased sensitivity, we investigated on the sensitivity of general type and p-i-n type diode. we designed microchannel size width max 10um, min 5um depth max 10um, reservoir size max 100um, min 2mm. Fabrication of microfluidic devices in glass substrate by glass wet etching methods and glass to glass fusion bonding. The p-i-n diode has higher sensitivity than photodiode. Considering these results, we fabricated p-i-n diodes on the high resistive($4k{\Omega}{\cdot}cm$) wafer into rectangle and finger pattern and compared internal resistance of each pattern. The internal resistance of p-i-n diode can be decreased by the application of finger pattern has parallel resistance structure from $571\Omega$ to $393\Omega$.

• Journal of Sensor Science and Technology
• /
• v.24 no.3
• /
• pp.155-158
• /
• 2015

In this paper, in-situ heat cooling with temperature monitoring is reported to solve thermal issues in electric vehicle (EV) batteries. The device consists of a thick graphene cooler on top of the substrate and a platinum-based resistive temperature sensor with an embedded heater above the graphene. The graphene layer is synthesized by using chemical vapor deposition directly on the Ni layer above the Si substrate. The proposed thick graphene heat cooler does not use transfer technology, which involves many process steps and does not provide a high yield. This method also reduces the mechanical damage of the graphene and uses only one photomask. Using this structure, temperature detection and cooling are conducted simultaneously using one device. The temperature coefficient of resistance (TCR) of a $1{\times}1mm^2$ temperature sensor on 1-$\grave{i}m$-thick graphene is $1.573{\times}10^3ppm/^{\circ}C$. The heat source cools down $7.3^{\circ}C$ from $54.4^{\circ}C$ to $47.1^{\circ}C$.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.11
• /
• pp.5419-5435
• /
• 2017

The construction of panoramic images on smartphones and low-powered devices is a challenging task. In this paper, we propose a new approach for smoothly stitching images on mobile phones in the presence of moving objects in the scene. Our main contributions include handling moving object problems, reducing processing time, and generating rectangular panoramic images. First, unique and robust feature points are extracted using fast ORB method and a feature matching technique is applied to match the extracted feature points. After obtaining good matched feature points, we employ the non-deterministic RANSAC algorithm to discard wrong matches, and the hommography transformation matrix parameters are estimated with the algorithm. Afterward, we determine precise overlap regions of neighboring images and calculate their absolute differences. Then, thresholding operation and noise removal filtering are applied to create a mask of possible moving object regions. Sequentially, an optimal seam is estimated using dynamic programming algorithm, and a combination of linear blending with the mask information is applied to avoid seam transition and ghosting artifacts. Finally, image-cropping operation is utilized to obtain a rectangular boundary image from the stitched image. Experiments demonstrate that our method is able to produce panoramic images quickly despite the existence of moving objects.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.2
• /
• pp.168-173
• /
• 2012

This paper presents a new human identification algorithm using partial features of the uncovered portion of face when a person wears a mask. After the face area is detected, the feature is extracted from the eye area above the mask. The identification process is performed by comparing the acquired one with the registered features. For extracting features SIFT(scale invariant feature transform) algorithm is used. The extracted features are independent of brightness and size- and rotation-invariant for the image. The experiment results show the effectiveness of the suggested algorithm.