• Title/Summary/Keyword: Filtering and detection

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Statistical Image Processing using Java on the Web

  • Lim, Dong Hoon;Park, Eun Hee
    • Communications for Statistical Applications and Methods
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    • v.9 no.2
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    • pp.355-366
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    • 2002
  • The web is one of the most plentiful sources of images. The web has an immediate need for image processing technology in Java. This paper provides a practical introduction to statistical image processing using Java on the web. The paper describes how images are represented in Java and deals with four image processing operations based on basic statistical methods: point processing, spatial filtering, edge detection and image segmentation.

Forgery Detection Scheme Using Enhanced Markov Model and LBP Texture Operator in Low Quality Images (저품질 이미지에서 확장된 마르코프 모델과 LBP 텍스처 연산자를 이용한 위조 검출 기법)

  • Agarwal, Saurabh;Jung, Ki-Hyun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.31 no.6
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    • pp.1171-1179
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    • 2021
  • Image forensic is performed to check image limpidness. In this paper, a robust scheme is discussed to detect median filtering in low quality images. Detection of median filtering assists in overall image forensic. Improved spatial statistical features are extracted from the image to classify pristine and median filtered images. Image array data is rescaled to enhance the spatial statistical information. Features are extracted using Markov model on enhanced spatial statistics. Multiple difference arrays are considered in different directions for robust feature set. Further, texture operator features are combined to increase the detection accuracy and SVM binary classifier is applied to train the classification model. Experimental results are promising for images of low quality JPEG compression.

Crack detection in concrete slabs by graph-based anomalies calculation

  • Sun, Weifang;Zhou, Yuqing;Xiang, Jiawei;Chen, Binqiang;Feng, Wei
    • Smart Structures and Systems
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    • v.29 no.3
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    • pp.421-431
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    • 2022
  • Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the sub-blocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.

Impulse Noise Detection Using Self-Organizing Neural Network and Its Application to Selective Median Filtering (Self-Organizing Neural Network를 이용한 임펄스 노이즈 검출과 선택적 미디언 필터 적용)

  • Lee Chong Ho;Dong Sung Soo;Wee Jae Woo;Song Seung Min
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.3
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    • pp.166-173
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    • 2005
  • Preserving image features, edges and details in the process of impulsive noise filtering is an important problem. To avoid image blurring, only corrupted pixels must be filtered. In this paper, we propose an effective impulse noise detection method using Self-Organizing Neural Network(SONN) which applies median filter selectively for removing random-valued impulse noises while preserving image features, edges and details. Using a $3\times3$ window, we obtain useful local features with which impulse noise patterns are classified. SONN is trained with sample image patterns and each pixel pattern is classified by its local information in the image. The results of the experiments with various images which are the noise range of $5-15\%$ show that our method performs better than other methods which use multiple threshold values for impulse noise detection.

Detection and Tracking of Time Varying Power System Frequencies and Harmonics using Subband Adaptive Filtering (적응 부밴드 필터링을 이용한 전력계통 시변 주파수와 고조파 검출 및 추적)

  • Sohn, Sang-Wook;Choi, Hun;Bae, Hyeon-Deok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.4
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    • pp.679-687
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    • 2009
  • In this paper, a subband filtering and adaptive prediction technique for analyzing harmonics in power systems is presented. In this method, the filter banks are designed to decompose odd and even order harmonics separately. The adaptive prediction has been employed reduce the transient and white noise effect in time varying harmonics detecting and tracking. The frequencies and amplitudes of the decomposed harmonics are estimated by recursive algorithm. To demonstrate the performances of the developed technique, computer simulations to the signal with the time-varying frequency and THD are carried out.

A Modified Adaptive Switching Median Filter for Image Restoration (영상복원(映像復原)을 위한 변형(變形)된 적응(適應) 스위칭 메디안 필터)

  • Jin, Bo;Kim, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.7
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    • pp.1373-1379
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    • 2007
  • A modified adaptive switching median filter for impulse noise removal, which has the noise detection step and the noise filtering step, is proposed in this paper. In the noise detection step, we use the detection threshold which is earned by calculating the intensity differences between pixels nearby with each other in localized window, to determine whether the pixels in the image are noise or not. Then in the noise filtering step, we will only remove the corrupted pixels and remain the good pixels. By the noise detection result, we can easily get the local noise density of the image, and use it to consider the filtering mask size and the times of filtering iteration according to different localized noise corruptions. For Setting the simulation result, we compared the proposed method to conventional median filters with several test images corrupted by various impulse noise densities. We also use the peak signal-to-noise ratio (PSNR) to evaluate restoration performance, the simulation results demonstrate that the proposed method shows better results than other median-based type filters.

A Study on the Enhanced Filtering for the Removal of BEMF in BLDC Motors

  • Moon, Yu-Sung;Choi, Jae-Hyun;Kim, Jung-Won
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.310-313
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    • 2019
  • This paper used the majority function to digitally filter back-electromotive force as an explanation of the Brushless DC MOTOR control algorithm. The cause and improvement of motor noise, which are operating in close proximity to high frequency sources, did not use conventional low pass filter and comparator elements. Also, they repeatedly output a noise-free BEMF signal for the input value of the majority detection filtering. These filtering steps can help reduce costs and minimize the area of a PCB by requiring relatively little hardware.

Spatial Compare Filter Based Real-Time dead Pixel Correction Method for Infrared Camera

  • Moon, Kil-Soo
    • Journal of the Korea Society of Computer and Information
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    • v.21 no.12
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    • pp.35-41
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    • 2016
  • In this paper, we propose a new real-time dead pixel detection method based on spatial compare filtering, which are usually used in the small target detection. Actually, the soft dead and the small target are cast in the same mold. Our proposed method detect and remove the dead pixels as applying the spatial compare filtering, into the pixel outputs of a detector after the non-uniformity correction. Therefore, we proposed method can effectively detect and replace the dead pixels regardless of the non-uniformity correction performance. In infrared camera, there are usually many dead detector pixels which produce abnormal output caused by manufactural process or operational environment. There are two kind of dead pixel. one is hard dead pixel which electronically generate abnormal outputs and other is soft dead pixel which changed and generated abnormal outputs by the planning process. Infrared camera have to perform non-uniformity correction because of structural and material properties of infrared detector. The hard dead pixels whose offset values obtained by non-uniformity correction are much larger or smaller than the average can be detected easily as dead pixels. However, some dead pixels(soft dead pixel) can remain, because of the difficulty of uncleared decision whether normal pixel or abnormal pixel.

Detection of the Optic Disk Boundary in Retinal Images Using Inward and Outward Curve Evolution (양방향 곡선 전개 방식을 이용한 망막영상에서의 시신경 원판 경계 검출)

  • Lee Sang-Kwan;Kim Seong-Kon
    • The Journal of the Korea Contents Association
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    • v.5 no.6
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    • pp.138-145
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    • 2005
  • This paper describes a technique for detecting the boundary of the optic disk in digital image of the retina using inward and outward curve evolution. This paper offers medical information about glaucoma progresses. For accurate boundary detection, image inpainting based on texture synthesis removes blood vessels crossing the optic disk. For removing noises and preserving boundary of optic disk in image inpainting process, the anisotropic diffusion filtering is necessary. After pre-processing, the optic disk boundary is determined using inward and outward curve evolution. The experimental results show that the algorithm is effective for detection of optic disk boundary.

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Identification Method of Geometric and Filtering Change Regions in Modified Digital Images (수정된 디지털 이미지에서 기하학적 변형 및 필터링 변형 영역을 식별하는 기법)

  • Hwang, Min-Gu;Cho, Byung-Joo;Har, Dong-Hwan
    • Journal of Korea Multimedia Society
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    • v.15 no.11
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    • pp.1292-1304
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    • 2012
  • Recently, digital images are extremely forged by editors or advertisers. Also, amateurs can modify images throughout easy editing programs. In this study, we propose identification and analytical methods for the modified images to figure out those problems. In modified image analysis, we classify two parts; a filtering change and a geometric change. Those changes have an algorithm based on interpolation so that we propose the algorithm which is able to analyze a trace on a modified area. With this algorithm, we implement a detection map of interpolation using minimum filter, laplacian algorithm, and maximum filter. We apply the proposed algorithm to modified image and are able to analyze its modified trace using the detection map.