• Title/Summary/Keyword: Edge preservation

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Edge-Preserving Iterative Reconstruction in Transmission Tomography Using Space-Variant Smoothing (투과 단층촬영에서 공간가변 평활화를 사용한 경계보존 반복연산 재구성)

  • Jung, Ji Eun;Ren, Xue;Lee, Soo-Jin
    • Journal of Biomedical Engineering Research
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    • v.38 no.5
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    • pp.219-226
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    • 2017
  • Penalized-likelihood (PL) reconstruction methods for transmission tomography are known to provide improved image quality for reduced dose level by efficiently smoothing out noise while preserving edges. Unfortunately, however, most of the edge-preserving penalty functions used in conventional PL methods contain at least one free parameter which controls the shape of a non-quadratic penalty function to adjust the sensitivity of edge preservation. In this work, to avoid difficulties in finding a proper value of the free parameter involved in a non-quadratic penalty function, we propose a new adaptive method of space-variant smoothing with a simple quadratic penalty function. In this method, the smoothing parameter is adaptively selected for each pixel location at each iteration by using the image roughness measured by a pixel-wise standard deviation image calculated from the previous iteration. The experimental results demonstrate that our new method not only preserves edges, but also suppresses noise well in monotonic regions without requiring additional processes to select free parameters that may otherwise be included in a non-quadratic penalty function.

Habitat Types of Wintering Season Wildbirds Depending on Land Use, Hanam (하남시 토지이용현황에 따른 겨울철 야생조류 서식유형 분석 연구)

  • Kim, Jeong-Ho
    • Journal of Environmental Science International
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    • v.15 no.11
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    • pp.1077-1086
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    • 2006
  • This study aims at analyzing relationships between land use and habitat types of winter wildbirds to provide basic understanding of ecosystem for preservation and restoration of urban ecosystem in the future. The research area is Hanam City. Researches on land use types showed Hanam City had 79.1% of greenspace and openspace, but intensive urban development has been taking place in greenspace that is adjacent to urban districts. This has brought the problems of lack of greenspace in urban districts and damages to cultivated areas and grassland. A total of 61 and 8,642 populations of winter wildbird species were observed in research areas. Paradoxornis webbiann(16.91), Passer montanus(11.93), Pica pica(6.88) were dominant species. When they were divided according to habitat types, 20 species of interior species, 8 species of interior-edge generalist species, 12 species of edge species and 3 species of urban species were observed. When which land use type was mostly served as wildbirds habitats was examined, urban species(3 species and 290 populations) was a dominant species in urban districts while in greenspace and openspaece, water species(19species and 3,075 populations) including winter migratory birds was. Among greenspace and openspaece, edge species was dominant in forest while urban species was a dominant species in cultivated areas. This shows there is a need to improve diversity of wildbirds through restoration of cultivated areas in the central part of Hanam City.

Reduction of Speckle Noise in Images Using Homomorphic Wavelet-Based MMSE Filter with Edge Detection (에지 영역을 고려한 호모모르픽 웨이브렛 기반 MMSE 필터를 이용한 영상 신호의 스펙클 잡음 제거)

  • 박원용;장익훈;김남철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.11C
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    • pp.1098-1110
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    • 2003
  • In this paper, we propose a homomorphic wavelet-based MMSE filter with edge detection to restore images degraded by speckle noise. In the proposed method, a noisy image is first transformed into logarithmic domain. Each pixel in the transformed image is then classified into flat and edge regions by applying DIP operator to the image restored by homomorphic directional MMSE filter. Each pixel in flat region is restored by homomorphic wavelet-based MMSE filter. Each pixel in edge region is restored by the weighted sum of the output of homomorphic wavelet-based MMSE filtering and that of homomorphic directional MMSE filtering. The restored image in spatial domain is finally obtained by applying the exponential function to the restored image in logarithmic domain. Experimental results show that the restored images by the proposed method have ISNR improvement of 3.3-4.0 ㏈ and ${\beta}$, a measurement parameter on edge preservation, improvement of 0.0103-0.0126 and superior subjective image quality over those by conventional methods.

A study on the method of the high-speed de-interlacing using the visual weighted filter in the post-processing of HDTV (HDTV 후단 처리부에서의 시각적 가중 필터를 이용한 고속 De-interlacing 기법 연구)

  • 정장훈;최연식
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.1
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    • pp.141-148
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    • 1998
  • We propose an efficient method of de-interlacing in the post-pocessing of HDTV signal. Since the proposed method considers human visual weight, it gives the better performance in the edge information preservation than that of the median filter. The processing time of the proposed method is twice faster than median filter, therefore the proposed method is suitable for the real-time de-interlacing in the post-processing of HDTV signal.

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A Study on Modified Weighted Filter for Edge Preservation in AWGN Environments (AWGN 환경에서 에지 보존을 위한 변형된 가중치 필터에 관한 연구)

  • Kwon, Se-Ik;Hwang, Yeong-Yeun;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.661-663
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    • 2016
  • Corruption occurs in the process of processing image signal and the corruption changes the pixel value within the image to damage the original information. AWGN(additive white Gaussian noise) is a representative example. For filters to remove AWGN, there are filters such as MF(mean filter), WF(wiener filter), and AWMF(adaptive weighted mean filter). However images processed through standard previous filters lock preservation characteristics in edge areas. Therefore, threshold value is applied for processing on the standard deviation of the local mask in this study and if the standard deviation is smaller than the threshold value, it is not filtered and if the value is bigger than the threshold value, the study suggested an algorithm that processes using weighted value utilizing standard deviation.

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Super Resolution Algorithm using TV-G Decomposition (TV-G 분해를 이용한 초해상도 알고리즘)

  • Eum, Kyoung-Bae;Beom, Dong-Kyu
    • Journal of Digital Contents Society
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    • v.18 no.8
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    • pp.1517-1522
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    • 2017
  • Among single image SR techniques, the TV based SR approach seems most successful in terms of edge preservation and no artifacts. But, this approach achieves insufficient SR for texture component. In this paper, we proposed a new TV-G decomposition based SR method to solve this problem. We proposed the SVR based up-sampling to get better edge preservation in the structure component. The NNE used the relaxed constraint to improve the NE. We used the NNE based learning method to improve the resolution of the texture component. Through experimental results, we quantitatively and qualitatively confirm the improved results of the proposed SR method when comparing with conventional interpolation method, ScSR, TV and NNE.

A Study on the Build of Equipment Predictive Maintenance Solutions Based on On-device Edge Computer

  • Lee, Yong-Hwan;Suh, Jin-Hyung
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.4
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    • pp.165-172
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    • 2020
  • In this paper we propose an uses on-device-based edge computing technology and big data analysis methods through the use of on-device-based edge computing technology and analysis of big data, which are distributed computing paradigms that introduce computations and storage devices where necessary to solve problems such as transmission delays that occur when data is transmitted to central centers and processed in current general smart factories. However, even if edge computing-based technology is applied in practice, the increase in devices on the network edge will result in large amounts of data being transferred to the data center, resulting in the network band reaching its limits, which, despite the improvement of network technology, does not guarantee acceptable transfer speeds and response times, which are critical requirements for many applications. It provides the basis for developing into an AI-based facility prediction conservation analysis tool that can apply deep learning suitable for big data in the future by supporting intelligent facility management that can support productivity growth through research that can be applied to the field of facility preservation and smart factory industry with integrated hardware technology that can accommodate these requirements and factory management and control technology.

Changes in Curve-Angle of Blade during Salting of Chinese Cabbage (배추의 소금절임중 엽신의 휘임도 변화)

  • Kim, Mi-Gyeong;Kim, Il-Du;Kim, Sun-Dong
    • Food Science and Preservation
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    • v.4 no.2
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    • pp.163-171
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    • 1997
  • This study was undertaken to investigate changes m curve angle of Chinese cabbage blade during salting at various concentration(10, 15, 20, 25%) of salt to evaluated salting degree by curve angle during salting at 20$^{\circ}C$. Salt concentration of brine, the amount of water elution, salt penetration of the tissue(salt concentration of Chinese cabbage), weight loss and texture were investigated. Correlation relation between the above factors and curve angle were determined. The curve angles by method of holding the edge of the Chinese cabbage blade was measured. The curve angles of the mesophyll were proportional to salting time and salt concentration, but slope of line equation showed higher than that of mid-rib. The ideal method of salting evaluation by curve angle was MCA-MRC (the measuring curve angle of mid-rib C) at each concentration of salt. The results of curve angle when reached 3% salt of Chinese cabbage tissue calculated by MCA-MRC at 10, 15, 20 and 25% salting were 57$^{\circ}$, 43$^{\circ}$, 36$^{\circ}$, and 33$^{\circ}$, respectively. And salting times calculated by the same conditions were 19, 12.5, 9.1 and 4.4hours, respectively.

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Modified Median Filter for Impulse Noise Removal (임펄스 잡음 제거를 위한 변형된 메디안 필터)

  • Long, Xu;Kim, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.2
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    • pp.461-466
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    • 2013
  • As the technology of the digital information age has developed rapidly, lots of research has been done on the digital image processing techniques, such as the image restoration. However, the SM(Standard Median) filter is a typical method of recovering the image which are corrupted by the impulse noise, this method will also reduce the quality of image by generating an error in the edge region. In this paper, in order to restore the corrupted images in the impulse noise environment, a modified median filter algorithm is proposed, which uses the pixels as the center and takes double mask. By using the double mask, we are succeeded in acquiring the excellent performance on noise-canceling, edge preservation, and also in improving the quality of image.

EFFICIENT SPECKLE NOISE FILTERING OF SAR IMAGES (SAR 영상의 SPECKLE 잡음 제거)

  • 김병수;최규홍;원중선
    • Journal of Astronomy and Space Sciences
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    • v.15 no.1
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    • pp.175-182
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    • 1998
  • Any classification process using SAR images presupposes the reduction of multiplicative speckle noise, since the variations caused by speckle make it extremely difficult to distinguish between neighboring classes within the feature space. Therefore, several adaptive filter algorithms have been developed in order to distinguish between them. These algorithms aim at the preservation of edges and single scattering peaks, and smooths homogeneous areas as much as possible. This task is rendered more difficult by the multiplicative nature of the speckle noise the signal variation depends on the signal itself. In this paper, LEE(Lee 1908) and R-LEE(Lee 1981) filters using local statistics, local mean and variance, are applied to RADARSAT SAR images. Also, a new method of speckle filtering, EPOS(Edge Preserving Optimal Speckle)(Hagg & Sties 1994) filter based on the statistical properties of speckle noise is described and applied. And then, the results of filtering SAR images with LEE, R-LEE and EPOS filters are compared with mean and median filters.

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