• Title/Summary/Keyword: Median Filtering

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Tracking Object Movement via Two Stage Median Operation and State Transition Diagram under Various Light Conditions

  • Park, Goo-Man
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.4
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    • pp.11-18
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    • 2007
  • A moving object detection algorithm for surveillance video is here proposed which employs background initialization based on two-stage median filtering and a background updating method based on state transition diagram. In the background initialization, the spatiotemporal similarity is measured in the subinterval. From the accumulated difference between the base frame and the other frames in a subinterval, the regions affected by moving objects are located. The median is applied over the subsequence in the subinterval in which regions share similarity. The outputs from each subinterval are filtered by a two-stage median filter. The background of every frame is updated by the suggested state transition diagram The object is detected by the difference between the current frame and the updated background. The proposed method showed good results even for busy, crowded sequences which included moving objects from the first frame.

Enhancement of noisy image sequence using order statistic-adaptive weighted average hybrid filters (순서 통계형-적응 가중평균 혼성필터를 이용한 잡음화된 영상열의 향상)

  • 박순영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.1
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    • pp.193-204
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    • 1997
  • In this research we propose the design of the Order Statistic-Adaptive Weighted Average Hybrid(OS-AWAH) filter which can suppress noise from the corrupted image sequence effectively while preserving the image structure. The proposed filter combines the desirable properties of the order static based spatial filter which can preserve the image structure while reducing noise and the adaptive weighted average based temporal filter which can adapt the filtering weights according to the amount of motion without motion estimation. Performance characteristics of the OS-AWAH filter in noisy sequences containing moving step edges are investigated throuth computer simulations and compared with the median based filters such as 3-D WM(weighted median) filter, MMF (multistage median filter), ADCWM(adaptive directional center weighted median) filter. The visual evaluations are also carried out by applyin gthe filters to the real images. The statistical analysis and experimental reslts show that the OS-AWAH filter is effective in preserving image structures while suppressing noise effectively without motion compensation preprocessing.

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Color Image Filter using an Enhanced Fuzzy Method (개선된 퍼지 기법을 이용한 컬러 영상 필터)

  • Kim, Kwang Baek;Lee, Byung Kwan
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.11
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    • pp.27-32
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    • 2012
  • In this paper, we propose a fuzzy method that improves the existing problem of the fuzzy filtering algorithm. The proposed fuzzy filtering algorithm separates R, G, and B channels from the color image. Mask information was extracted from separated channels and the brightness of the mean value and median value for channels was applied in the function of the proposed fuzzy method to calculate the membership and achieve application in the inference rule. Also, the membership degrees of R, G, and B were used to distinguish the possibility of noise. The proposed fuzzy method selected three membership functions. If noise is distinguished, the noise is eliminated by selecting the median value or mean value as the relevant pixel value according to the degree of noise. By applying the proposed method in color images, it was verified that the proposed method is more effective in eliminating noise when compared with the conventional fuzzy filtering method.

Image Dehazing Enhancement Algorithm Based on Mean Guided Filtering

  • Weimin Zhou
    • Journal of Information Processing Systems
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    • v.19 no.4
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    • pp.417-426
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    • 2023
  • To improve the effect of image restoration and solve the image detail loss, an image dehazing enhancement algorithm based on mean guided filtering is proposed. The superpixel calculation method is used to pre-segment the original foggy image to obtain different sub-regions. The Ncut algorithm is used to segment the original image, and it outputs the segmented image until there is no more region merging in the image. By means of the mean-guided filtering method, the minimum value is selected as the value of the current pixel point in the local small block of the dark image, and the dark primary color image is obtained, and its transmittance is calculated to obtain the image edge detection result. According to the prior law of dark channel, a classic image dehazing enhancement model is established, and the model is combined with a median filter with low computational complexity to denoise the image in real time and maintain the jump of the mutation area to achieve image dehazing enhancement. The experimental results show that the image dehazing and enhancement effect of the proposed algorithm has obvious advantages, can retain a large amount of image detail information, and the values of information entropy, peak signal-to-noise ratio, and structural similarity are high. The research innovatively combines a variety of methods to achieve image dehazing and improve the quality effect. Through segmentation, filtering, denoising and other operations, the image quality is effectively improved, which provides an important reference for the improvement of image processing technology.

Performance analysis of improved hybrid median filter applied to X-ray computed tomography images obtained with high-resolution photon-counting CZT detector: A pilot study

  • Lee, Youngjin
    • Nuclear Engineering and Technology
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    • v.54 no.9
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    • pp.3380-3389
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    • 2022
  • We evaluated the performance of an improved hybrid median filter (IHMF) applied to X-ray computed tomography (CT) images obtained using a high-resolution photon-counting cadmium zinc telluride (CZT) detector. To study how the proposed approach improves the image quality, we measured the noise levels and the overall CT-image quality. We established a CZT imaging system with a detector length of 5.12 cm and thickness of 0.3 cm and acquired phantom images. To evaluate the efficacy of the proposed filter, we first modeled two conventional median filters. Subsequently, we were able to achieve a normalized noise power spectrum result of ~10-8 mm2, and furthermore, the proposed method improved the contrast-to-noise ratio by a factor of ~1.51 and the coefficient of variation by 1.55 relative to the counterpart values of the no-filter image. In addition, the IHMF exhibited the best performance among the three filters considered as regards the peak signal-to-noise ratio and no-reference-based image-quality evaluation parameters. Thus, our results demonstrate that the IHMF approach provides a superior image performance over conventional median filtering methods when applied to actual CZT X-ray CT images.

Image Retrieval using Median Filtering in Color RGB Feature Information Extraction (칼라 RGB 특징정보 추출에 Median 필터링을 이용한 영상검색)

  • Kang, Gwang-Won;Park, Tae-Su;Seo, Kyung-Sik;Park, Jong-An
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.275-276
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    • 2006
  • 본 논문에서는 내용기반 영상검색을 보다 효과적인 알고리즘 설계를 위해 칼라 RGB 특징정보 추출에 median 필터링을 이용한 영상검색의 성능을 분석하였다. 칼라영상에서 각각의 R,G,B칼라영상으로 나눈 후 일정크기의 블록으로 분할하여 R,G,B 각각의 중간값을 추출하고 크기순과 레벨의 특징자를 이용한 영상검색 기법을 제안한다.

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Reference Image Update on the Security System for the Moving Object Detection (침입자 검출을 위한 보안 시스템에서의 참고영상 갱신 방안에 관한 연구)

  • 안용학
    • Convergence Security Journal
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    • v.2 no.2
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    • pp.99-108
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    • 2002
  • In this paper, I propose a reference image updating algorithm for Intruder Detection System using a difference image method that can reliably separate moving objects from noisy background in the image sequence received from a camera at the fixed position. The proposed algorithm consists of four process determines threshold value and quantization, segmentation of a moving object area, generation of adaptive temporary image that removes a moving object area, and updates reference image using median filtering. The test results show that the proposed algorithm can generate reference image very effectively in the noisy environment.

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APPLICATIONS OF SELF-REFERENCING METHOD TO THE VIRGO CLUSTER SPIRALS

  • Chung, Eun-Jung;Kim, Hyo-Young;Rhee, Myung-Hyun
    • Journal of The Korean Astronomical Society
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    • v.38 no.4
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    • pp.371-384
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    • 2005
  • Self-referencing method in revised-OTFTOOL is a new method in On-The-Fly(OTF) observation mode. It uses the source free regions of the observed frame as references instead of the OFFs references. We already analyzed and discussed its proprieties and advantages in the previous paper. In this paper, we make a statistical study about the self-referencing method by applying it to OTF mapping data of 27 Virgo spiral galaxies. We found that the self-referencing method solves the crooked baseline problem for every datacube. It straightens the baseline, and conserves the emissions. Compared with other data processing, the median filtering task 'mwflt' in AIPS, to use self-referencing method is more effective and safe not only to straighten the baseline but also to conserve the emission. For the strong CO galaxies, the data obtained by self-referencing method shows scarcely any difference from those reduced by conventional OFFs references and AIPS median filtering in the range of uncertainties. Undetected CO emissions in datacubes of conventional OFFs references are also not detected in those of self-referencing method. The self-referencing method is expected to save the observing time and simplify data reduction processes. Besides this, using self-referencing method will offer emission-free references more safely.

Pacman Game Using Recognition of Hand Movement from Game Industry (게임 산업에서 손동작 인식을 이용한 팩맨 게임)

  • Shin, Seong-Yoon;Rhee, Yang-Won
    • Journal of Korea Society of Industrial Information Systems
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    • v.17 no.3
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    • pp.51-57
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    • 2012
  • Pacman is known as the terminator of the loved classic game in the world. In this paper, classic pacman game without using a keyboard or a mouse we should be able to play the game with simple hand gestures. In other words, It use motion game to be a substitute for the hand direction key using the center coordinates. Also, movements of the monster is to be replaced depending on your hand movements by extracting a pointer of hand taking pictures in the MFC dialog using Cam. In this paper, YCbCbr image is convert to RGB images to extract skin color, and multiplication operations and hybrid median filtering was used in order to obtain better images. And it is used to obtain movement of the hand area based on obtain the center of gravity of the hand region.

The development of Fetal Heart Rate monitoring system based on DSP processor (DSP 프로세서를 이용한 태아심음 및 자궁수축감시장치의 개발)

  • Jnag, D.P.;Kim, K.H.;Lee, Y.H.;Lee, Y.K.;Bak, M.I.;Lee, D.S.;Kim, S.I.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.320-324
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    • 1996
  • Digital fetal monitoring system based on the personal computer combined with the digital signal processing board was implemented. The DSP board acquires and digitally processes ultrasound fetal Doppler signal for digital rectification, FIR filtering, autocorrelation function calculation, its peak detection and MEDIAN filtering. The personal computer interfaced with the DSP board is in charge of graphic display, hardcopy, data transmission and on-line analysis of fetal heart rate change including and variability. I used a recursive technique for autocorrelation function computation method and MEDIAN filter which can greatly reduce the amount of calculation and accuracy. I also implemented analysis algorithm of fetal heart rate change based on normal fetal sample data in order to exact diagnosis.

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