• Title/Summary/Keyword: 훼손원인

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The Estimation of Soil Erosion Factors of Cutting Slope using RC Helicopter Image (무선조종 헬기 영상을 이용한 절취단면의 토사유출인자 산정)

  • Cho, Yong-Jae;Lee, Young-Do;Jung, Beom-Seok
    • Journal of the Korean Association of Geographic Information Studies
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    • v.10 no.2
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    • pp.82-90
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    • 2007
  • Recently, the development project is conducting disaster effect estimation to breed disaster, and cope these disaster beforehand provoking soil erosion and flood. Therefore, it is important to analyze and reduce of these disaster. In this study, it is intended to extract LS and C factors of soil erosion through the digital image. The photogrammetric technique, which employs the Remote Control Helicopter equipped with a non-metric digital camera, was used for the efficient survey and analysis of cutting slopes. As a result, we obtain more objective value of soil erosion factor using digital image.

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Salt & Pepper Noise Removal Using Histogram and Spline Interpolation (히스토그램 및 Spline 보간법을 이용한 Salt & Pepper 잡음 제거)

  • Ko, You-Hak;Kwon, Se-Ik;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2017.10a
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    • pp.691-693
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    • 2017
  • As the modern society develops into the digital information age, the application field is gradually expanded and used as an important field. The image data is deteriorated due to various causes in the process of transmitting the image, and typically there is salt & pepper noise. Conventional methods for removing salt & pepper noise are somewhat lacking in noise canceling characteristics. In this paper, we propose a weighted filter using the histogram of the image damaged by salt & pepper noise and a spline interpolation method according to the direction of the local mask.

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Wavelet-based Algorithm for Signal Reconstruction (신호 복원을 위한 웨이브렛기반 알고리즘)

  • Bae, Sang-Bum;Kim, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.1
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    • pp.150-156
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    • 2007
  • Noise is generated by several causes, when signal is processed. Hence, it generates error in the process of data transmission and decreases recognition ratio of image and speech data. Therefore, after eliminating those noises, a variety of methods for reconstructing the signal have been researched. Recently, wavelet transform which has time-frequency localization and is possible for multiresolution analysis is applied to many fields of technology. Then threshold-and correlation-based methods are proposed for removing noise. But, conventional methods accept a lot of noise as an edge and are impossible to remove the additive white Gaussian noise (AWGN) and the impulse noise at the same time. Therefore, in this paper we proposed new wavelet-based algorithm for reconstructing degraded signal by noise and compared it with conventional methods.

A Study on Impulse Noise Removal on using Directional Mask (방향성 마스크를 이용한 임펄스 잡음 제거에 관한 연구)

  • Hong, Sang-Woo;An, Young-Joo;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.10a
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    • pp.795-797
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    • 2014
  • Image treatment has grown in its necessity in many fields due to the development of display technology used in smart phones and tablet computers. In digital imaging technology, noise is created by many causes during the process of acquiring, transmitting and treating image data. Therefore, this paper suggests a median filter that is more competent in removing noise by taking into account the direction when restoring noisy images that have been damaged by impulse noise. In order to verify the noise removal characteristics, PSNR(peak signal to noise ratio) was used for comparison against existing methods.

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Image Reduction Filter for Edge Preservation in Salt and Pepper Noise Environments (Salt and Pepper 잡음 환경에서 에지 보존을 위한 영상 복원 필터)

  • Kwon, Se-Ik;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.953-955
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    • 2016
  • Degradation is occurred in the process of the signal transmission in the image processing system due to various reasons. Degradation is noise addition in the image signal and the representative one to cause degradation is salt and pepper noise. Therefore, image restoring filter was suggested in this article to apply and process weighted value by the changes of each directional pixel upon breakdown of local mask with 8 directions in order to restore the damaged image in the environment of salt and pepper noise. In addition, peak signal to noise ratio (PSNR) was used to compare the existing method as the objective determinant standard of the improvement effect.

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Evaluation of water engineering ability for the Byeokgolje (벽골제의 수공학적 능력 평가)

  • Jang, Myung Ho;Kim, Min Hwan
    • Proceedings of the Korea Water Resources Association Conference
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    • 2021.06a
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    • pp.286-286
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    • 2021
  • 벽골제는 전북 김제시에 위치하고 있으며 우리나라의 고대 저수지이다. 벽골제는 고대 농경사회의 대규모 토목사업으로 건설되었다. 약 2.5km의 제방이 현존하고 있다. 축조 시기는 삼국시대 서기 330년이다. 이후 통일신라 원성왕(AD.790)과 고려 현종 및 인종 때 보수되었으며 조선 태종(AD.1415)에 대대적인 보수를 하였다. 세종 2년(AD.1420)에 심한 폭우로 유실되었다. 그 후 일제강점기 1925년에 김제 간선수로로 개조함으로써 원형이 크게 훼손되었다. 벽골제는 우리나라뿐만 아니라 동아시아 고대 저수지로서 중요하다. 벽골제의 축조방식(부엽공법)과 측량기술은 일본 오사카부의 사야마이케(저수지)에 영향을 주었다. 사야마이케는 고대저수지로서 원형이 보존되어 있으며 유네스코 세계 유적으로 등재하기 위한 준비가 충실하게 진행되어 왔다. 본 연구에서는 벽골제가 고대저수지로서 가치를 인정받고 보존하기 위해 발굴되고 있다. 더불어 벽골제의 수공학적 능력 평가가 필요하다고 판단된다. 벽골제 유역을 대상으로 현재 지형과 최근이 수문자료를 이용하여 평가하였다. 발굴된 벽골제를 기준으로 유역을 설정하였다. 벽골제 유역 특성을 토대로 강우 분석을 수행하여 홍수량과 벽골제를 기준으로 수면적과 용적을 산정하였다. 벽골제에는 5개 수문이 있으며 3개는 Sluice Gate 형식(장생거, 중심거, 경장거)이고 2개의 월류형 형식(수여거, 유통거)으로 구성되어 있다. 최근에 수여거는 발굴 중이며 유통거는 미발굴 상태이다. 발굴된 수문의 규모를 토대로 수문 개방 정도에 따라, 웨어의 첨단고에 따라, 제내지의 수위를 조합하여 시나리오를 구성하였다. 시나리오에 따라서 최고수위를 산정하여 벽골제의 능력을 평가하였다. 이를 근거로 벽골제의 붕괴 원인을 추정해 보았다.

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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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    • 2021.05a
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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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Change of Flora of Damaged Land in Juwangsan National Park for Five Years (2010~2014) (주왕산국립공원 내 훼손지의 5년간(2010~2014년) 식물상 변화)

  • You, Juhan;Kim, Mijin
    • Journal of Environmental Impact Assessment
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    • v.25 no.4
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    • pp.233-247
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    • 2016
  • The purpose of this study is to offer the basic data for management of National Park by surveying and analysing the change of flora of damaged lands in Juwangsan National Park, Korea. In cause of occurring the damaged lands, site-1 was the vegetation damage by stamping, the removing Gwangamsa of site-2, 3, 4 and the removing Naewon village of site-5, 6, 7. Whole sites are caused by the artificial disturbance and interference. The numbers of flora were summarized as 135 taxa including 52 families, 109 genera, 116 species, 2 subspecies and 17 varieties in whole sites. The status of flora by sites, site-6 is the largest number of 52 taxa, site-1 is the lowest of 23 taxa. The rare plant is 1 taxa, 4 taxa of endemic plants, 10 taxa of specific plants by floristic region, 9 taxa of naturalized plants and 1 taxa of invasive alien plant. In the results of analysis about the change of coverage ratio, for this shrub layer, site-7 was changed to the most $0%{\rightarrow}50%$, and the herb layer, site-5 was changed to the most $75%{\rightarrow}95%$. In case of the change of species numbers, most sites tended to increase in the sites introduced different species or generated by the growth. It is contemplated that is similar to the restoration with the surrounding natural vegetation that is in progress is a transition occurs with the passage of time. In the dominant species, the shrub layer is Fraxinus sieboldiana, Lespedeza bicolor, Rhus javanica, Lespedezamaximowiczii, Salix koreensis and Zelkova serrata, and Miscanthus sinensis var. purpurascens, Oplismenus undulatifolius, Artemisia princeps, Bothriochloa ischaemum and Erigeron annuus of herb layer. In the results of analysing Naturalized Index(NI) and Urbanized Index(UI), NI was increased or decreased this phenomenon with the lapse of time, UI was the most increase. In particular, the increase in UI is due to the transition process, the pioneering plant, naturalized plant was imported to continue.

Analyzing the Occurrence Trend of Sediment-Related Disasters and Post-Disaster Recovery Cases in Mountain Regions in N orth Korea Based on a Literature Review and Satellite Image Observations (문헌 및 위성영상에 기초한 북한의 산지토사재해 발생경향 및 복구사례 분석)

  • Kim, Kidae;Kang, Minjeng;Kim, Suk Woo
    • Journal of Korean Society of Forest Science
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    • v.110 no.3
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    • pp.419-430
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    • 2021
  • This study investigated spatiotemporal trends of sediment-related disasters in North Korea from 1960 to 2019 and post-disaster recovery cases based on a literature review and satellite images. Results showed that occurrence status of sediment-related disasters was initially externally reported in 1995 (during the Kim Jongil era); their main triggering factor was heavy summer rainfall. Furthermore, forest degradation rate was positively correlated with population density (R2 = 0.4347, p = 0.02) and occurrence number of sediment-related disasters was relatively high on the west coast region, where both variables showed high values. This indicates that human activity was a major cause of forest degradation and thus, significantly affected sediment-related disasters in mountain regions. Finally, sediment- related disasters due to shallow landslides, debris flow, and slow-moving landslides were observed in undisturbed forest regions and human-impacted forest regions, including terraced fields, opencast mines, forest roads, and post-wildfire areas, via satellite image analysis. These disaster-hit areas remained mostly abandoned without any recovery works, whereas hillside erosion control work (e.g., treeplanting with terracing) or torrent erosion control work (e.g., check dam, debris flow guide bank) were implemented in certain areas. These findings can provide reference information to expand inter-Korean exchange and cooperation in forest rehabilitation and erosion control works of North Korea.

Deep learning algorithm of concrete spalling detection using focal loss and data augmentation (Focal loss와 데이터 증강 기법을 이용한 콘크리트 박락 탐지 심층 신경망 알고리즘)

  • Shim, Seungbo;Choi, Sang-Il;Kong, Suk-Min;Lee, Seong-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.4
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    • pp.253-263
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    • 2021
  • Concrete structures are damaged by aging and external environmental factors. This type of damage is to appear in the form of cracks, to proceed in the form of spalling. Such concrete damage can act as the main cause of reducing the original design bearing capacity of the structure, and negatively affect the stability of the structure. If such damage continues, it may lead to a safety accident in the future, thus proper repair and reinforcement are required. To this end, an accurate and objective condition inspection of the structure must be performed, and for this inspection, a sensor technology capable of detecting damage area is required. For this reason, we propose a deep learning-based image processing algorithm that can detect spalling. To develop this, 298 spalling images were obtained, of which 253 images were used for training, and the remaining 45 images were used for testing. In addition, an improved loss function and data augmentation technique were applied to improve the detection performance. As a result, the detection performance of concrete spalling showed a mean intersection over union of 80.19%. In conclusion, we developed an algorithm to detect concrete spalling through a deep learning-based image processing technique, with an improved loss function and data augmentation technique. This technology is expected to be utilized for accurate inspection and diagnosis of structures in the future.