• Journal of applied mathematics & informatics
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• v.41 no.5
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• pp.1115-1128
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• 2023

In this paper, a novel hybrid method for multi-focus image fusion is proposed. The method combines the advantages of wavelet transform-based methods and focus-measure-based methods to achieve an improved fusion result. The input images are first decomposed into different frequency sub-bands using the discrete wavelet transform (DWT). The focus measure of each sub-band is then calculated using the Laplacian of Gaussian (LoG) operator, and the sub-band with the highest focus measure is selected as the focused sub-band. The focused sub-band is sharpened using an unsharp masking filter to preserve the details in the focused part of the image.Finally, the sharpened focused sub-bands from all input images are fused using the maximum intensity fusion method to preserve the important information from all focus images. The proposed method has been evaluated using standard multi focus image fusion datasets and has shown promising results compared to existing methods.

• Journal of the Korean Graphic Arts Communication Society
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• v.6 no.1
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• pp.67-74
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• 1988

Absorption rates of oxygen in water soluble inks on the printing rollers were measured. As a results of experiments, could be obtained the data of rates of absorption of oxygen in 4 kinds of water soluble inks, and found the difference of absorption rate of oxygen on the parallel plates and rotating rolles.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.163-168
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• 2002

본 논문에서는 워터마크의 기본적인 요구사항인 비가시성(invisibility)을 유지하면서 강인함(robustness)을 최대로 하기 위해 워터마크를 삽입할 때 인간시각 특성(Human Visual System, HVS)을 이용한다. 특히, 주파수 마스킹(frequency masking), 공간 마스킹(spatial masking), 그리고 움직임 마스킹(motion masking)을 결합한 전역마스킹(global masking) 기법을 제안한다. 주파수 마스킹은 프레임을 DCT 변환한 후 주파수 민감도 표(frequency sensitivity table)를 이용해 위치 정보를 구한다. 공간 마스킹은 밝기(luminance) 및 윤곽선(edge) 정보를 이용해서 구하며. 움직임 마스킹은 이웃하는 프레임간의 움직임 변화를 이용하여 프레임간의 상관성을 고려한다. 본 논문에서는 키(key) 값에 의해 발생된 랜덤시퀀스와 로고의 배타적 논리합(exclusive OR)에 의해 결합된 워터마크를 전역 마스킹 결과에 따라 압축되지 않은 비디오 프레임에 직접 적용했으며, 실험을 통해 MPEG 부호화 및 재부호화 공격에 대해서 제안한 방법이 강인함을 확인했다.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.156-165
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• 2014

This paper is the first investigation on the effect of flow control methods on the part load performance in a spark ignition engine. For comparison of the methods, two control devices, port throttling and masking, were applied to a conventional engine without any design change of the intake port. Steady flow evaluation shows that steady flow rates per unit opening area and swirl ratio are very low compared with the port throttling and saturated from mid-stage valve lift, however, swirl increases slightly as the lift is higher in case of 1/4 masking control. In the part load performance, the effect of simple port throttling on lean misfire limit expansion is limited and insufficient; on the other hand a masking improves the limit considerably without any port modification for increasing swirl. Also the results show that the intake flow control improves the combustion with following two mechanisms: stratification induced by the combination of the flow pattern and the fuel injection timing attribute to ignition ability and the intensified flow ensure fast burn. In addition fuel consumption reduces under the flow controls and the reduction rate is different according to the operation conditions and control methods. At the Stoichiometric and/or low speed and low load the throttling method is more advantageous; however vice versa at lean and high load condition. Finally, the throttling is more efficient for HC reduction than masking, on the other side the NOx emissions increase under the masking and decrease under the port throttling compared with conventional port scheme.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.335-336
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• 2000

A psychoacoustic model based noise shaping method is proposed, where noise's presence with a host signal will not be perceptually noticeable. The derivation of imperceptible noise levels from the masking thresholds of the signal involves a deconvolution associated with the spreading function in the psychoacoustic model, which results in an ill-conditioned problem. In this paper, the problem is formulated as a constrained optimization, and it is demonstrated that the solution provides noise shaping where the noise excitation level conforms to the masking thresholds of the signal.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.82-84
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• 2001

Real-Time Linux는 기존의 Linux에 실시간 기능을 추가한 것으로서, 태스크 스케줄링 방법은 우선순위 기반의 스케줄링 방법을 사용한다. 그러나, 태스크의 개수가 많아지면 가장 높은 우선순위의 태스크를 찾는데 걸리는 시간이 태스크 개수에 비례해서 많이 걸린다. 이러한 이유로 태스크의 개수가 제한적일 수밖에 없다. 본 논문에서는 우선순위별로 서로 다른 목록을 유지하고, Bit Masking 기법을 사용함으로써 가장 높은 우선순위 태스크를 선택하는데 걸리는 시간을 상수시간으로 줄이고 각 태스크들의 시그널을 처리하는 부분을 좀더 효율적으로 처리하도록 함으로써 Real-Time Linux의 실시간 스케줄링 기능을 개선하였다.

• The Korean Journal of Applied Statistics
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• v.24 no.1
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• pp.127-136
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• 2011

Multiplicative noise model is the one of popular method for masking continuous variables. In this paper, we propose the transformation on the variable to which random noise was multiplied. An advantage of the masking method using proposed transformation is that the masking data users can obtain the unbiased values of mean and variance of original (unmasked) data. We also consider the data utility and correlation structure of variables when we apply the proposed multiplicative noise scheme. To investigate the properties of the method of masking based on multiplicative noise, a simulation study has been conducted using the 2008 Householder Income and Expenditure Survey data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2961-2967
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• 2014

Nowadays, a private protection act has come into effect which demands for the protection of personal image information obtained by the CCTV. According to this act, the object out of interest has to be mosaicked such that it can not be identified before the image is sent to the investigation office. Meanwhile, the demand for digital videos obtained by CCTV is also increasing for digital forensic. Therefore, due to the two conflicting demands, the demand for a solution which can automatically mask an object in the CCTV video is increasing and related IT industry is expected to grow. The core technology in developing a target masking solution is the object tracking technique. In this paper, we propose an object tracking technique which suits for the application of CCTV video object masking as a postprocess. The proposed method simultaneously uses the motion and the color information to produce a stable tracking result. Furthermore, the proposed method is based on the centroid shifting method, which is a fast color based tracking method, and thus the overall tracking becomes fast.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.227-232
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• 2008

The masking effect of chlorine on algae-related taste and odor(T&O) compounds has long been an important issue for water suppliers. In this study, masking experiments with chlorine were performed on two kinds of treated water and one of raw water. After adding chlorine(0 to 0.8 mg/L) to water samples, odor intensity was evaluated by a newly developed sensory method(2-out-of-5 odor test) for three days along with the measurement of residual chlorine concentration. Even though the relationship between the residual chlorine concentration and odor reported by the sensory analysts was not always coincident, it was proved that residual chlorine more than a certain concentration could completely mask both added geosmin and naturally occurring T&O compounds. For the sand-filtered water spiked with 10 ng/L of geosmin, 0.12-0.18 mg/L of residual chlorine was necessary to achieve complete masking. In the case of GAC-filtered water, 10 ng/L of spiked geosmin was completely masked by 0.15-0.1 mg/L of residual chlorine. Combined ozone and GAC was not enough to treat raw water spiked with 300 ng/L of geosmin. In this experiment, sensory analysts were able to detect earthy or musty odors from the treated water. From a masking experiment with raw water taken from the Daechung Reservoir, it was found that fishy odor was more difficult to mask with chlorine than earthy odor. As the chlorine residual declined, the analysts began to notice the original odor and the fishy odor was noticed earlier than the earthy odor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.7
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• pp.2938-2956
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• 2020

Objective image quality assessment (IQA) models have been developed by effective features to imitate the characteristics of human visual system (HVS). Actually, HVS is extremely sensitive to color degradation and complex texture changes. In this paper, we firstly reveal that many existing full reference image quality assessment (FR-IQA) methods can hardly measure the image quality with contrast and masking texture changes. To solve this problem, considering texture masking effect, we proposed a novel FR-IQA method, called Texture and Color Quality Index (TCQI). The proposed method considers both in the masking effect texture and color visual perceptual threshold, which adopts three kinds of features to reflect masking texture, color difference and structural information. Furthermore, random forest (RF) is used to address the drawbacks of existing pooling technologies. Compared with other traditional learning-based tools (support vector regression and neural network), RF can achieve the better prediction performance. Experiments conducted on five large-scale databases demonstrate that our approach is highly consistent with subjective perception, outperforms twelve the state-of-the-art IQA models in terms of prediction accuracy and keeps a moderate computational complexity. The cross database validation also validates our approach achieves the ability to maintain high robustness.