• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.4
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• pp.13-18
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• 2012

In this paper, we propose a noise estimation method for noise reduction. It is based on block and pixel-based noise estimation. We assume that an input image is contaminated by the additive white Gaussian noise. Thus, we use an adaptive Gaussian filter and estimate the amount of noise. It computes the standard deviation of each block and estimation is performed on pixel-based operation. The proposed algorithm divides an input image into blocks. This method calculates the standard deviation of each block and finds the minimum standard deviation block. The block in flat region shows well noise and filtering effects. Blocks which have similar standard deviation are selected as test blocks. These pixels are filtered by adaptive Gaussian filtering. Then, the amount of noise is calculated by the standard deviation of the differences between noisy and filtered blocks. Experimental results show that our proposed estimation method has better results than those by existing estimation methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.612-617
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• 2009

In a DCT coding, degradations called block artifact and mosquito noise are appeared in reconstructed pictures. They should be reduced in post processing after decoding without superabundant processing. However, an estimation of mosquito noise is rare because of its difficulty. To realize an estimation of mosquito noise level, we extract a block that mosquito noise will be easy to occur. Mosquito noise level is calculated at a selected side of the block. In this processing, only the sides of high probability block are used. Then, a block value is taken by averaging. Finally, the picture value is calculated by averaging of this. Estimation method is evaluated by using the MPEG-4 decoded pictures. Quantization scale of coding and the estimated mosquito noise level are compared. As the results, we recognize the proposed method gives almost reasonable mosquito block and absolute level. Father, adaptive filter is controlled by the estimated mosquito noise level. It is recognized that the high quality of decoded picture is kept and the mosquito noise is reduced effectively at the picture with degradation.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.57-62
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• 1994

In order to establish a prediction method for road traffic noise generated from actual traffic flow, a new approach is proposed for practical use. One block in urban road is regarded as one box in this study. This prediction method is able to treat any kind of road traffic noise generated from one block. The validity of the proposed prediction method has been experimentally confirmed by applying it to actually observed road traffic noise data. The correlation between observed and predicted noise level is good.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.1
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• pp.47-53
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• 2008

Blocking artefact noise is necessarily happened in compressed images using block-coded algorithms such as JPEC compressing algorithm. This noise is more recognizable especially in highly compressed images. In this paper, an algorithm is presented for reduction of blocking artefact noise using block division. Furthermore, we also mention about the median filter which is often used in image processing.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.8-14
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• 2001

In this paper, we present a new cost function for subband block adaptive algorithm and block conjugate gradient algorithm for noise cancellation of acoustic signal. For the cost function, we process the subband signals with data blocks for each subbands and recombine it a whole data block. After these process, the cost function has a quadratic form in adaptive filter coefficients, it guarantees the convergence of the suggested block conjugate gradient algorithm. And the block conjugate gradient algorithm which minimizes the suggested cost function has better performance than the case of full-band block conjugate gradient algorithm, the computer simulation results of noise cancellation show the efficiency of the suggested algorithm.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.129-137
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• 2000

The powertrain is an important factor for the interior and exterior noise behavior of the vehicle Thus, the noise vibration and harshness(NVH) behavior of an engine is becoming a major target of the powertrain development. This paper describes the analyses with the aim to reduce the vibration and noise of an advanced inline 4-cylinder diesel engine block by use of CAE methods. The characteristics of an engine block as a main excitation source of car interior noise is studied. Particularly, The effect of balance shaft to reduce the 2nd order engine excitation force is calculated by forced vibration and radiated noise analysis. The engine exitation forces are obtained under real operating conditions. It is shown that the reduction of vibration and noise level by adapting blancing shaft is well predicted and rediated noise is directly related to the surface velocity of engine block.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2568-2574
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• 2011

31 December 2012 will be the end of terrestrial analog broadcasting. Digital broadcasting will begin. The picture quality on analog broadcasting, was not a problem. but, In digital broadcasting, is a problem. Service for streaming on the digital broadcasting MPEG video compression. And the content is added block noise. These block noise measured by people's eyes. but, people's eyes is subjective. In this paper, the on-reference methods to detect block noise. And detected by measuring the distribution of block noise, to quantify the levels of block-noise. With this study, block noise by visual inspection using an automated tool, by being objective measure of information and communication will contribute to the development of the video.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.2
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• pp.93-100
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• 2008

In this paper, Low Noise Block down converter(LNB) is designed for a Ka-band satellite television receiver only(TVRO) using commercially available MMIC. Designed Low Noise Block down-converter is composed of three stage amplifiers involving input noise matched at first amplification stage, image reject band pass filter, frequency mixer and intermediate frequency amplification. Through LNB Module power budget to obtain gain and attenuation, Optimum LNB devices satisfying Ka-band LNB technical specification are selected. Experimental results of designed Ka-band LNB yields conversion gain of over $58{\pm}1dB$, noise figure of less than 1.5dB and phase noise of -94.6dBc @10KHz.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.25-34
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• 2012

The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of alternative methods to solve the social requirements of noise problems. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block for quiet pavement. The specimens, which is fixed hall-size, space, depth as the condition of this research, are analysed of noise reduction effect using different noise levels of vehicles. Judging from the analysis of test results with vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base and quiet asphalt surface showed a good alternative solution for decreasing traffic noise level, from 4dB to 9dB.

• Korean Journal of Occupational Health Nursing
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• v.21 no.3
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• pp.317-325
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• 2012

Purpose: This study was to examine the effects of noise block on anxiety and vital sign of gynecologic laparoscopic surgery. Methods: The data were collected from March to May 2011. Participants were sixty patients with gynecologic laparoscopic surgery, divided into 30 of experimental group and 30 of control group at C University hospital located in I city. The day before surgery, demographic data, trait-state anxiety and vital signs were measured at ward. After noise block, the data were measured using VAS anxiety and vital signs before anesthesia and in recovery room. And then state anxiety and vital signs were measured in ward after surgery. The data were analyzed by $x^2$-test, t-test, repeated measured ANOVA and Bonferroni comparison method using SPSS/WIN 19.0. Results: After conducting noise block program, the experimental group showed significant decrease in state anxiety and heart rate compared to those of the control group. But there were not significant differences in VAS anxiety, systolic pressure and diastolic pressure between two groups. Conclusion: This program can be regarded as an effective nursing intervention for the management of anxiety with gynecologic laparoscopic surgery.