• Title/Summary/Keyword: 공간 필터

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Two-Dimensional Filtering Through the Radon Transform (라돈변환을 이용한 2차원 필터링)

  • 원중선
    • Korean Journal of Remote Sensing
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    • v.14 no.1
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    • pp.17-36
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    • 1998
  • The Radon transform has been widely used in various techniques of digital image processing such as the computerized topography, lineament analysis in a remotely sensed image, slant-stack processing of seismic data, and so on. Compared to the Fourier transform, the utility of two-dimensional convolutional or correlational properties of the Radon transform, however, has been underestimated. We show that the two-dimensional convolution and correlation is respectively reduced to be one-dimensional convolution and correlation with respect to ρ in the Radon space. Therefore, one can achieve a two dimensional filtering by applying a simple one-dimensional convolution in the Radon space followed by an inverse Radon transform. Tests of the approach using FIR filters are carried out specifically for enhancing the ship wake in a RADARSAT SAR image. The test results demonstrate that the two-dimensional filtering through the Radon transform effectively enhance the ship wake features as well as reducing sea speckle in the image. Although two-dimensional convolution and correlation through the Radon transform are not so much useful as those through the courier transform in views of efficiency and effectiveness, it can be utilized to improve the quality of a digitally processed output when the process should be accompanied by the Radon transform such as topography and lineament analysis of SAR image.

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Video De-noising Using Adaptive Temporal and Spatial Filter Based on Mean Square Error Estimation (MSE 추정에 기반한 적응적인 시간적 공간적 비디오 디노이징 필터)

  • Jin, Changshou;Kim, Jongho;Choe, Yoonsik
    • Journal of Broadcast Engineering
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    • v.17 no.6
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    • pp.1048-1060
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    • 2012
  • In this paper, an adaptive temporal and spatial filter (ATSF) based on mean square error (MSE) estimation is proposed. ATSF is a block based de-noising algorithm. Each noisy block is selectively filtered by a temporal filter or a spatial filter. Multi-hypothesis motion compensated filter (MHMCF) and bilateral filter are chosen as the temporal filter and the spatial filter, respectively. Although there is no original video, we mathematically derivate a formular to estimate the real MSE between a block de-noised by MHMCF and its original block and a linear model is proposed to estimate the real MSE between a block de-noised by bilateral filter and its original block. Finally, each noisy block is processed by the filter with a smaller estimated MSE. Simulation results show that our proposed algorithm achieves substantial improvements in terms of both visual quality and PSNR as compared with the conventional de-noising algorithms.

Noise Removal Filter Algorithm using Spatial Weight in AWGN Environment (AWGN 환경에서 공간 가중치를 이용한 잡음 제거 필터 알고리즘)

  • Cheon, Bong-Won;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.207-209
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    • 2021
  • In recent years, with the development of artificial intelligence and IoT technology, automation and unmanned technology are in progress in various fields, and the importance of image processing such as object tracking, medical images and object recognition, which are the basis of this, is increasing. In particular, in systems requiring detailed data processing, noise reduction is used as a pre-processing step, but the existing algorithm has a disadvantage that blurring occurs in the filtering process. Therefore, in this paper, we propose a filter algorithm using modified spatial weights to minimize information loss in the filtering process. The proposed algorithm uses mask matching to remove AWGN, and obtains the output of the filter by adding or subtracting the output of the modified spatial weight. The proposed algorithm has superior noise reduction characteristics compared to the existing method and reconstructs the image while minimizing the blurring phenomenon.

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Design of Multiplierless 2-D State Space Digital Filters Based on Particle Swarm Optimization (PSO을 이용한 고속 2차원 상태공간 디지털필터 설계)

  • Lee, Young-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.4
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    • pp.797-804
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    • 2013
  • This paper presents an efficient design method of multiplierless 2-D state space digital filter based on a particle swarm optimization(PSO) algorithm. The design task is reformulated as a constrained minimization problem and is solved by our newly developed PSO algorithm. To ensure the stability of the designed 2-D state space digital filters, a stability strategy is embedded in the basic PSO algorithm. The superiority of the proposed method is demonstrated by several experiments. The results show that the approximation error and roundoff noise of the resultant filters are better than those of the digital filters which designed by recently published filter design methods. In addition, the designed filters with power-of-two coefficients have only about 1/4 computational burden of the 2-D digital filters designed in the 2's complement binary representation.

Modified Spatial Division Average Filter for AWGN Noise Reduction (AWGN 잡음 제거를 위한 변형된 공간분할 평균필터)

  • Park, Hwa-Jung;Kwon, Mi-Rae;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.227-229
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    • 2021
  • The modern society is advancing from the analog era to the digital imaging era, and in line with the trend of this era, various imaging devices such as exploration robots, medical equipment, and CCTV are helping our daily life a lot. However, noises caused by various causes in digital images not only cause image deterioration, but also deteriorate and deteriorate image quality. A typical noise is AWGN, and types of filters to remove it include an average filter, a median filter, and an alpha-trimmed average filter, but these filters have a disadvantage in that they show somewhat inadequate noise reduction performance in the high frequency region. Therefore, in this paper, a modified spatial division average filter based on standard deviation is proposed to effectively reduce AWGN existing in the high frequency region of the image.

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Improved speech enhancement of multi-channel Wiener filter using adjustment of principal subspace vector (다채널 위너 필터의 주성분 부공간 벡터 보정을 통한 잡음 제거 성능 개선)

  • Kim, Gibak
    • The Journal of the Acoustical Society of Korea
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    • v.39 no.5
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    • pp.490-496
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    • 2020
  • We present a method to improve the performance of the multi-channel Wiener filter in noisy environment. To build subspace-based multi-channel Wiener filter, in the case of single target source, the target speech component can be effectively estimated in the principal subspace of speech correlation matrix. The speech correlation matrix can be estimated by subtracting noise correlation matrix from signal correlation matrix based on the assumption that the cross-correlation between speech and interfering noise is negligible compared with speech correlation. However, this assumption is not valid in the presence of strong interfering noise and significant error can be induced in the principal subspace accordingly. In this paper, we propose to adjust the principal subspace vector using speech presence probability and the steering vector for the desired speech source. The multi-channel speech presence probability is derived in the principal subspace and applied to adjust the principal subspace vector. Simulation results show that the proposed method improves the performance of multi-channel Wiener filter in noisy environment.

Introduction to Method of Space-efficient Bloom Filtering (공간 효율적인 블룸 필터링 방법의 소개)

  • Kang, Boo-Joong;Ro, In-Woo;Im, Eul-Gyu
    • Proceedings of the Korean Information Science Society Conference
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    • pp.1-4
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    • 2008
  • 블룸 필터는 간단하고, 공간 효율적인 자료 구조이다. 블룸 필터는 확률에 근거하여 어떤 데이터 집합을 표현하며, 어떤 데이터가 특정 데이터 집합에 속하는 지를 검사하는 멤버십 쿼리를 지원한다. 이런 멤버십 쿼리는 긍정 오류를 발생시키지만 블룸 필터의 파라미터들을 조정하여 긍정 오류를 최소화할 수 있다. 블룸 필터는 데이터가 공유의 필요성에 의해 전체 시스템에 걸쳐 물리적으로 퍼져있는 분산 시스템과 많은 양의 데이터를 다루기 위해 데이터베이스를 사용하는 시스템 그리고 실시간으로 멤버십 쿼리를 수행해야 하는 시스템 등에서 널리 사용되고 있다. 본 논문에서는 블룸 필터에 대해 알아보고 시스템의 목적에 따라 다양한 형태로 개량된 블룸 필터들에 대해 소개한다.

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Analyzing the Effectiveness of a Best Management Practice on Sediment Yields Using a Spatially Distributed Model (공간분포형 모델을 이용한 최적관리방안의 토사 유출 저감 효과에 관한 연구)

  • Lee, Taesoo
    • Journal of the Korean Geographical Society
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    • v.52 no.1
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    • pp.15-24
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    • 2017
  • Management of non-point sources for water quality control practice is complicating but very important. Sediments mainly from croplands are prioritized in non-point source management due to the sediment attached phosphorous. In this study, flow and sediment yields are modeled in Oenam watershed located in Hwasun, Jeollanam-do, a upstream of Juam Lake. A spatially distributed model and GIS(Geographic Information System) data was used to find out hot spots of sediment yields, to analyze the effectiveness of filter strips, and to visualize the effectiveness. The impacts of filter strips was estimated on the reduction of flow and sediments at 17.2% and 46.4% respectively when the filter strips were installed in the sub-watersheds with the most serious sediment yields.

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Plant Growth Responses and Indoor Air Quality Purification in a Wall-typed Botanical Biofiltration System (벽면형 식물바이오필터 내 식물 생육 및 실내공기질 정화)

  • Jung, Seul Ki;Chun, Man Young;Lee, Chang Hee
    • Korean Journal of Plant Resources
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    • v.28 no.5
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    • pp.665-674
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    • 2015
  • The final goal of this research is to develop a botanical biofiltration system, which combines green interior, biofiltering, and automatic irrigation, which can purify indoor air pollutants according to indoor space and the size of biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be more suitable for indoor space utilization. This study was performed to compare indoor air quality between the space adjacent to a botanical biofilter and the space away from the biofilter (control) without generation of artificial indoor air pollutants, and to evaluate plant growth depending on multiple floors within the biofilter. Each concentration of indoor air pollutants such as TVOCs, monoxide, and dioxide in the space treated with the biofilter was lower than that of control. Dracaena sanderiana ‘Vitoria’ and Epipremnum aureum ‘N Joy’ also showed normal growth responses regardless of multiple floors within the biofilter. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was effective for indoor air purification.

Comparative Analysis of LPF and HPF for Roads Edge Detection from High Resolution Satellite Imagery (고해상도위성영상에서 도로 경계 검출을 위한 고주파와 저주파 필터링 비교분석에 관한 연구)

  • Choi, Hyun;Kang, In-Joon
    • Journal of Korean Society for Geospatial Information Science
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    • v.14 no.3
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    • pp.3-11
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    • 2006
  • The need for edge detection about topography data from the high resolution satellite imagery is happening with increasing frequency according to many people utilize the its imagery as various fields recently. Many experts is recognizing of other GIS will make use of the road detection from the high resolution satellite imagery, including ITS (Intelligent Transportation Systems) and urban planning. This paper is comparative analysis of LPF (Low Pass Filtering) and HPF (High Pass Filtering) for roads edge detection from high resolution satellite imagery. As a result, LPF and HPF can be highlight selective pixels at edge area about input data. In case or applying to other techniques such as LPF for the same purpose, they aye more effective for wide road width which often cause the slight distortion of boundary or overall change of brightness values on the whole Image. Whereas, HPF has ability to enhance selectively detailed components in a target image.

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