Seong-Jun Kang

FPGA implementation of image watermarking algorithm for a digital camera

In this paper, we present an FPGA implementation of a watermarking-based authentication algorithm for a digital camera to authenticate the snapshots in a manner that any changes of contents in the still image will be reflected in the embedded watermark. All components of a digital camera and a watermark algorithm are implemented in VHDL, simulated, synthesized and loaded into an FPGA device. To achieve the semifragile characteristics that survive a certain amount of compression, we employ the property of DCT coefficients quantization proposed by Lin and Chang (2000). The binary watermark bits are generated by exclusive ORing the binary logo with pseudo random binary sequence. Then watermark bits are embedded into the LSBs of DCT coefficients in the medium frequency range. The system consists of three main parts: image capture and LCD controller, watermark embedding part, and camera control unit. The FPGA implemented digital camera is tested to analyze the performance. It is shown that the watermarking algorithm can embed the watermark into the original image coming from a sensor much faster than the software implementation and the embedded image is easily transmitted to the PC by using the USB interface. The quality of the transmitted image is also comparable to the one implemented by a software algorithm.

The role of EL2 in the infrared transmission images of defects in semi-insulating GaAs

Infrared transmission images from GaAs semi insulating wafers were considered for years as directly related to the quantum absorption by electrons on fundamental states of deep centers, especially EL2. The satisfying correspondence of these images with the dislocations revealed by etching or X ray topography or infrared tomography led to the opinion that a strong concentration of EL2 centers was to be expected in the immediate vicinity of the dislocations. More recent work indicates that contrary to the expected behavior the photoquenching of transmission images at T=80K does not appreciably change the image structure itself but more largely the uniform background level of absorption. Such investigations show that the transmission images of isolated dislocations (Indium doped materials) or cell structures of tangled dislocations (undoped materials) can be partly attributed to scattered light; similar operation at T=10K removes the dark features associated to EL2 but still preserves the skeleton of the pattern which is due to scattering. A result of the measurements is that dislocations must not be considered any longer as inexhaustive EL2 reservoirs. The lifetime of the photoquenching mechanism is shown to vary differently for EL2 centers located close to the dislocations or in the matrix. In this paper we will develop the details of infrared image photoquenching experiments in the vicinity of dislocations; undoped and In doped GaAs materials will be shown. These results will be discussed in the light of surface etching experiments.

Content-Based Scene Change Detection of Video Sequence Using Hierarchical Hidden Markov Model

This paper presents a histogram and moment-based video scene change detection technique using hierarchical Hidden Markov Models(HMMs). The proposed method extracts two types of features from wavelet-transformed images. One is the histogram difference extracted from a low-frequency subband and the other is the normalized directional moment of double wavelet differences computed from high frequency subbands. The video segmentation process consists of two steps. A histogram-based HMM is first used to segment the input video sequence into three categories: shot, cut, and gradual scene changes. In the second stage, a moment-based HMM is used to further segment the gradual changes into fades, dissolves and wipes. The experimental results show that the proposed technique is more effective in partitioning video frames than the threshold-based method.

A Study on the DC parameter matching according to the shrink of 0.13㎛ technology

본 논문은 기존의 poly length만의 축소와 달리 입, 출력 소자를 포함한 core 디바이스의 0.13㎛ 디자인을 10% 축소하는 것으로 여러 채널 길이에 따른 body effect와 doping profile simulation을 해석하였다. 축소 전의 DC 파라미터 매칭을 위하여 게이트 산화막의 decoupled plasma nitridation 처리와 LDD(Lightly Doped Drain) 이온주입 전 TEOS(Tetraethylortho silicate) 산화막 100Å 그리고 LDD 이온주입을 22o tilt-angle(45o twist-angle)로 최적화하였고 그 결과 축소 전의 5%의 범위에서 매칭됨을 확인하였다.

A study on Flicker Noise Improvement by Decoupled Plasma Nitridation

본 논문은 0.13㎛ 기술의 디자인을 10% 축소하는데 기존의 로직 디바이스만의 축소와는 달리 로직뿐 아니라 입, 출력 회로의 축소에 관한 것이다. 게이트 산화막(1.2V)을 decoupled plasma nitridation(DPN) oxide로 변경함으로써 flicker 노이즈를 축소 전 공정에 비해 1/3-1/5배 감소됨을 확인하였다. 또한, 축소에 의한 피할 수 없는 문제는 일반적인 metal insulator metal(MIM)의 캐패시터 문제이다. 이를 해결하기 위하여 20% 높은 MIM 캐패시터(1.2fF/㎛²)를 개선하고 그 특성을 평가하였다.

A study on the Hot Carrier Injection Improvement of I/O Transistor

반도체 소자 제조에서 비용 절감을 위한 공정기술의 스케일링 가속화 경향에 따라 축소기술에 대한 요구가 증가되고 있다. 축소에 따른 또 다른 가장 큰 문제점의 하나는 Hot Carrier Injection (HCI) 특성의 열화이다. 이는 축소 과정에서 생기는 불가피한 가장 큰 이슈중의 하나이며, 특히 입출력 소자에 있어 극복하기 어려운 부분이다. 이의 개선을 위해 유효 채널 길이를 늘이고자 LDD 임플란트 공정 이전에 산화막이 추가되었고, 또한 I/O LDD 임플란트 공정의 이온 입사 각도를 최적화함으로써, LDD 영역에서 E-field 열화 없이 HCI 규격을 만족할 수 있었다.

A study on the solution prepared system design for analysis automation

Petrochemical complex has been a lot of research for the development of a more mature product and analysis for mid-process and finished products is essential in these process. But these analyzes are still by hand work samples being manufactured in many parts. Moreover they are exposed to hazardous chemical and such as the analysis is being made in a very poor working conditions. In this paper, in order to solve such problems the multi control system has been developed for the automated analysis. In addition, the organic behavior of these systems and the development of a program for the automated applied, and throughout the experiment to verify the reliability of this device for the accuracy of the dosing pumps for the standard solution prepared with a range of error of was able to get a very good experimental results.

Infrared Imaging and a New Interpretation on the Reverse Contrast Images in GaAs Wafer

IC 기판의 가장 중요한 성질들의 하나는 넓은 영역에 걸쳐 균일해야만 한다는 것이다. 웨이퍼 결함 분석의 다양한 물리적 접근 방법 중에서 적외선 조사 기법에 특별한 관심이 모아지고 있다. 특히, 높은 공간적 분해력을 가지고 있는 근적외선 흡수 방법은 반-절연 GaAs 내의 결함들을 직접적으로 관찰하는데 이용되고 있다. 적외선 전송에 기초를 둔 이 기법은 신속하고 비파괴 적이다. 이 방법은, 직접적으로 GaAs 반도체의 적외선 영상은 결함의 광흡수 작용에 기인한 것임을 밝히고 있다. 반-절연 GaAs 내의 EL2에 관련된, 비 균일 적으로 분포된 결함들의 적외선 흡수 영상에서 콘트라스트가 반전되는 현상에 대해 새로운 모델을 제시하고 있다. 저온 포토퀀칭 실험은, 직접적인 방법으로, GaAs 웨이퍼의 콘트라스트 반전 영상은 밴드갭의 지엽적인 변동이나 전하 재분포에 의한 것이 아니라 흡수와 산란의 두 메커니즘에 의한 것임을 증명하고 있다.

Study on the Trap Parameters according to the Nitridation Conditions of the Oxide Films

In this paper, the MIS(: Metal-Insulator-Semiconductor) Capacitor with the nitrided-oxide by RTP are fabricated to investigate the carrier trap parameters due to avalanche electron injection. Two times turn-around phenomenon of the flatband voltage shift generated by the avalanche injection are observed. This shows that electron trapping occurs in the oxide film at the first stage. As the electron injection increases, the first turn-around occures due to a positive charge in the oxide layer. After further injection, the curves turns around once again by electron captured. Based on the experimental results, the carrier trapping model for system having multi-traps is proposed and is fitting with experimental data in order to determine trap parameter of nitrided-oxide.

Influence of the process conditions for the amorphous silicon on the HSG-Si formation

In this paper, the processing conditions of the amorphous silicon film growth were investigated the effect in forming the HSG-Si on the surface of the storage electrode. As a result, when the amorphous silicon film phosphorus concentration is greater than , HSG-Si is not formed correctly and showed the concentration dependency of HSG formation. Also, the optimum condition of the phosphorus concentration for amorphous silicon and HSG thickness are and , respectively, because of the HSG thickness over the create to bit failure according to a short of the electrodes and the electrode.